I am a licenced Radio Amateur and should be aware of the majority of this information. However I found it very interesting and enlightening, thank you for the presentation mate!
Those goofy T-wires provided with the purchase of a receiver work fine for most people in or near urban areas looking to get only a couple of favorite channels, which is most people in the country now. We who live in rural areas appreciate your information to help us getting those distant broadcasts.
The T-wire antenna can also be arranged with the top of the T vertical, and try to have it up as high as possible. It may be of benefit to add an extension to the twin lead to gain that height.
Thank you for your advice about a whip antenna, and about what its optimal length should be. I have a Sony receiver with a 75 ohm coaxial connection. I found a 30-inch (75 cm) whip antenna with a 30 inch cord, and it works perfectly ... no amplifier needed! I propped it up in a window with a venetian blind, and I now get great reception of an FM station I like, that is 60 miles away! A cheap and very effective solution ... thank you!
@@gioscervelo I would be interested in hearing from you if you added a ground plane. The ground plane should be at least 30" in a radius at the base of the vertical antenna and attached to the shield braid of the coaxial cable.
I learned more about FM in this video than trying to research it on my own in years. Thank you Bob for your knowledge I am going to have to try your methods. The higher the antenna the better the signal, so true. DXing is awesome.
I mounted four of these folded dipoles vertically and used RG62, 93 ohm cable with a balun at each antenna. I used a spectrum analyzer to phase each antenna and use the correct length of RG62 to raise the impedance of each antenna to 3oo ohms unbalanced. When the antennas were connected together, the unbalance impedance became 75 ohms. Since the FM broadcast band is rather narrow, I could easily phase the antennas Outstanding reception!
Patrick, wow, you really took the bull by the horns and wrestled it into submission! It is not likely that most have access to a spectrum analyzer to handle such a job, or the patience to do it. Congratulations on your fine work and results!!
I just thought about building a radio antenna at my property in Park county, Co., was sitting at Chatfield reservoir listening to am radio, thought "this is quaint, I like AM radio" then the lightbulb went off, I could erect an antenna and get really good radio signal up there, long story long, found Bob here explaining proper signal capture and antenna positioning and he's is an engineer so he knows his stuff, thanks Bob!
Thanks for sharing such an interesting video. I am from Cuba and I always was a FM band lover. I had several antennas to "catch" radio stations from Florida and one of my favorites was a 7-element yagi, along with a 3-step booster which I put right on the mast about 1 foot from the dipole. It was sealed and protected from rain. Oh man! That setup worked like a charm!!! Power supply was down by the tuner and I used the same 75 ohm coaxial cable to power up the Booster. Amazing guys! I wonder how many stations I'd get here with such a system!!! Okay, thanks again and till your next video.
Bob: Thank you for this video. Couple questions: 1) Where can I purchase a folded dipole antenna for FM radio reception? 2) I plan to mount it on my TV antenna mast. My TV antenna is a "Televes 148883 Antenna Ellipse Mix ". 2) Where on the mast, relative to the TV antenna, should I mount the FM dipole. Many thanks. Jim King, Saratoga County, NY
Jim, the easiest and most readily available is the circular Stellar Labs model 30-2435, Outdoor FM Antenna, and just straighten it out. Do a search for the lowest price, generally in the $20 to $30 dollar range. It is 55" when straightened, so it may have a bit less sensitivity at the low end of the FM band, but the higher band will be a bit better !! I would recommend that the vertical FM dipole be mounted below the TV antenna, and that the top of the FM dipole be below the lowest element of the TV antenna. Please update with your results !
The easiest and most readily available is the circular Stellar Labs model 30-2435, Outdoor FM Antenna, and just straighten it out. Do a search for the lowest price, generally in the $20 to $30 dollar range. It is 55" when straightened, so it may have a bit less sensitivity at the low end of the FM band, but the higher band will be a bit better !!
You are very welcome ! Please see th-cam.com/video/fbudkK9LzWY/w-d-xo.html for a comparison of two FM HD tuners, in the case the Dennon receiver tuner has poor reception...
Nice video! Thanks very much! Didn't know that circular polarization was pretty much standard. Stove-Pipe Dipole Armed with that information about circular polarization, I built a dipole out of two pieces of 8" (trade size) / 7" (actual size) galvanized HVAC duct. Each arm of the dipole is 690mm or a bit over 27" each. I put a 1" space between the ends where the 75 Ohm CATV cable connects. I did not use a balun of any sort, as the two pieces of stove-pipe make a very good match to 75 Ohms at the middle of the FM band, and I was not too concerned about disruption of the pattern because of feed line currents. Because of the large 7" diameter of the stovepipe, the antenna is fairly broad band. The antenna seems to work well. I have made some measurements like those you give in your video, so far just for the stovepipe dipole (which I hung vertically in my attic and connected via 75 Ohm CATV cable to my radio in the basement). Have not yet made measurements on other antennas on hand. Noise in FM Broadcast Reception This was all in an effort to clean up some "steam" or "scratchiness" that seems to be always present in music received through this radio. I am a bit perplexed how to get rid of it. Even though my radio shows a good strong signal (as I assessed by measuring the voltage at the S-meter output of the FM IF chip), I still hear some scratch in the music. Do I not have a strong enough signal? Perhaps the scratchiness is because of the demodulation method used in the radio? The radio, by the way, is a Kenwood KR-A46 AM-FM stereo receiver., about 1987 vintage. It is frequency synthesizer-controlled, and I have not attempted to align it, though I do have the factory service manual that describes the alignment procedure. I just picked it up at a thrift store recently, so I don't have a great deal of experience with it. Maybe a fully analog FM receiver would have less "scratch"? Thanks again for the very informative video. Good engineering! Max
Thank you for your comments ! It is noteworthy that this video urged you on to try building a similar vertical dipole !! With that said, I would suggest that you try a new FM tuner that uses a NXP, STM, or TI digital FM/AM HD chipset. These new tuners can be had for around $200, and if you look at th-cam.com/video/fbudkK9LzWY/w-d-xo.html for the comparison of two of these popular tuners, I am sure you by getting one of these will get rid of any background scratchy static !!!
I'm fortunate to live in a signal-rich urban area and pull strong signals with just an old 300-ohm floppy dipole strip, which I reposition, depending upon atmospheric conditions. That, and a receiver with a good FM stage, has served me well these past 60 years. Our village is the western-most portion of San Diego suburbs and it's a straight shot up the coast to the high antennas sited in the mountains east of the Los Angeles Basin. As I am 400 feet from the Pacific, there is virtually no multi-path phenomenon, because I am sticking out from the continent enough to allow line-of-sight between my cheapo dipole ribbon and the transmitters high atop the coast range of mountains to the north. So I get good signal strength and quite a bit of separation, even though it's almost 100 miles between us! My Fisher receiver, circa 1978, was made with Avery Fisher's patents in Japan and has one of the best FM stages I've encountered, but my two Marantz receivers were equally as good, too. This gear benefitted from American know-how and Japanese expertise in manufacture. I believe that accounts for the popularity of the big super-receivers of the 1970s today. They offer enough stable power to drive even an inefficient speaker system and great FM reception, too. I found no superiority in my high-end Tandberg separate components with their miles of interconnecting cables which may or may not have been picking up RF signals, given the traffic density here. I know it sound like heresy, but I think receivers with their short coupling paths between sections result in a cleaner signal than individual amp-preamp-tuner arrays and all the potential corrosion effects at contact points in this marine (saline) environment. At least it provides less chance of tripping over yards of cables and neatens up your listening area. Wives and sweethearts like the sound, but often balk at the hardware scattered about. I first dropped a needle on a record in 1940, so I've been around the platter several million times! Thanks, Robert, for a thoroughly professional and useful presentation. My brother Jimmy was Chief Plant Engineer for Pacific Bell here and had 12 patents of his assigned to AT&T over the years, so I have some experience with your area of expertise.
Thank you very much for your detailed description of your reception conditions ! You are truly very lucky to be in the situation you are in !! Thank you for your kind comments on my presentation !!!
The turnstile antenna mentioned at 3:00 and again at 10:40 can be made to work more-or-less omnidirectionally if the section of twin lead connecting the two crossed elements is 1/4 wavelength long. At 98 Mhz this would be about 28". It's called phase-quadrature. It works - the reception pattern is a cloverleaf. The length shown on the vid appears to be random. These things can be pretty frequency-critical.
Rick, thank you for your comment ! Yes, you are correct, but I was advising for an omnidirectional reception pattern that the single dipole yields ! The cloverleaf has four nulls....
The easiest and most readily available is the circular Stellar Labs model 30-2435, Outdoor FM Antenna, and just straighten it out. Do a search for the lowest price, generally in the $20 to $30 dollar range. It is 55" when straightened, so it may have a bit less sensitivity at the low end of the FM band, but the higher band will be a bit better !!
Very informative! After watching this video I went home and straightened the elements on the Stellar Labs 30-2435 "round dipole" that's been sitting in my basement, unused. I also flipped the mast mounting bracket on the center support and slid it to the far end so it can be easily mounted to a mast, offset at a right angle. Mounted in this configuration I assume the built-in transformer will be more susceptible to water intrusion, so I will bypassing it and using a pigtail balun.
Two more steps in complexity, for another 6dB gain, would be to have two vertical dipoles end-to-end with a shorted quarter-wave stub between them. I used that for pirate broadcasting long ago. It worked very well. The impedance around the middle of the stub is 200Ω balanced. If you use a half wavelength (times whatever the velocity factor is) of 52Ω coax to make a balun to feed it there, it works out perfectly.
That is a good suggestion, but some people may not have the readily available height to use that technique. Thank you very much for your reply and good suggestion !!
Great video! I have a number of high quality component FM tuners fed by a variety of antenna systems in different rooms of my house: Horizontal folded dipole, vertical dipole, and my garage tuner has two yagis facing west (to Cleveland, Ohio) and south (to Kent, Ohio), switched to provide the best tuner input. We live low in the valley of the Chagrin River so FM reception is...challenging.
I've got. 50 years in the radio business, with 20 years installing FM / TV antennas. Even though I have FIOS, I still have antennas on my roof. I get better quality HDTV off my antennas than I do with Fios. Just recently I've been experimenting with an out door FM antenna and found this information very useful. The first thing intone morning I will flip my folded dipole to the vertical position as you advise. I'm looking forward to good results and will,let your know. I forgot all about the circular orientation of FM. I am anxious for good results. If you want to know something about radio ask a Ham!
The easiest and most readily available is the circular Stellar Labs model 30-2435, Outdoor FM Antenna, and just straighten it out. Do a search for the lowest price, generally in the $20 to $30 dollar range. It is 55" when straightened, so it may have a bit less sensitivity at the low end of the FM band, but the higher band will be a bit better !!
Thank you for your reply. I don't know why I wasn't notified of it. By dumb luck I ended up getting a windstorm damaged Stellar Labs 30-2460 a coworker was going to trash for nothing. I took out the part that looks like a folded dipole. Unlike the Stellar Labs 30-2435 it is one piece. I like that. I straightened it out the best I could and hooked 300 ohm 18awg ladder line to it, then ran the ladder line directly to my vintage receivers 300 ohm antenna connection points. I now have the best reception I can remember. I'm thinking of duplicating this antenna with 3/8 or 1/2 inch OD copper tubing to see if there's any gains to be had from the copper construction. Thanks for pointing these designs out.
I appreciate the video. The TH-cam might have been an adder to what you were doing there and understanding you will possibly concentrating more on a primary plan But I wish you would have got more into the yagi question being you only did the one video I think and there's not much else out here. Again thank you so much that you did the video in the first place..! was glad I was able to re-watch it to remember the vertical Mount idea. Apparently no one is in my shoes at all, are the number of us is so small that it might as well be Z-Ro because search engines send us nowhere. It seems like no one wants to bring in one station for dear life and it's unheard of for anyone to even try if it's over 70 MI. Humbug I only can receive one station that plays any kind of music that I like to hear. We receive kfzx from no trees, Texas (Gardendale but west of ) and pick it up in Marfa, Texas we're probably 200 mi from Gardendale Texas by road,but the station transmitter Tower is 130 MI by flight. I have a picture of my ZR2 setting in front of it. The usual 100,000 Watts 102.1 been classic rock for at least 20 years but now there's a bit of 80s touch added in the calling it The eagle. It's Received on a discone 21' off the ground at 4,725' elev From 130 mi away! No Trees Texas is a high spot maybe 20 miles north west of Odessa. I had it hooked up to a yagi for a little bit and it did not do well at all but I had it horizontal and I think that was a huge mistake..? But I'm thinking now mostly I might have had a coax issue as well. More testing the discone is centered by a 54 mag wideband hf54 Diamond d130nj Which would apparently be a very good FM antenna for Omni work and maybe a little tuning would kick it off very well.. notch filter and I'm also imagining most would say the discount would just bring in way too much noise of all other frequencies. Don't use it and maybe don't need the notch..
Any antenna is better than nothing, but the marine band is in the frequency range between 156 and 174 MHz, and will not be optimized for the FM band of 88 to 108 MHz.
6:05 The ones I've had experience with are called "quasi-circular." Each antenna in the bay is a half-wave dipole, with a difference. Half of each element is a horizontal half circle, with the second half at a right angle to the first, one end pointing up, the other, down
Yes, that is correct. There are several FM and TV broadcast antenna manufacturers, and each have their own patents and copyrights to the ones that they make. It would be interesting to actually plot the polar patterns to measure the effectiveness.
Bob, I'm a novice at this, so I'm working with trial an error. It appears that the length of the antenna arms seems to matter. I've heard 29" and 30" in different videos for making antenna. The aluminum S unit/dipole that is better vertical then horizontal (05:35 in video) is clearly longer then 30" for each arm in the T. Is there a ratio that one tries to use to maximize signal strength reception? Basically, is more metal better then less metal for each arm? Would 60" arms of the T be twice as effective as 30" arms? I'm hooking up to a radio receiver in an apartment/office and there is no access to the attic, roof or above for an FM antenna to be mounted to anything. I stuck with 10 foot ceiling perhaps 20-25 feet of the ground, being on a second story of a two story building. Any thoughts on how to optimize this with out mortgaging the house to do it would be appreciated. Thanks
Chris, thanks for your comments and questions ! The 31" length of each arm in the antenna tunes it to the center of the FM frequency band, 98 MHz. If you make the arms 60", that would optimize the antenna for receiving a 49 MHz frequency. Just locate the antenna as high in elevation as possible, and if you have the desire to prefer only certain FM stations, get their broadcasting antenna location and place your antenna as close to their direction in the building as possible !! Thanks again !!
Newbee here. Can I purchase a good outdoor FM antenna or are there patterns for building one? I do not know how to connect the antenna to the lead going down. I am not even sure where to purchase materials any more as most DYI stores have closed in the area. I have a Channel Master TV antenna on a rotor for TV, but it is only for UHF and my wife sorely misses FM. I can have a second lead coming down for the FM. I have seen some circular and some horizontal flat (e.g. like the Channel Master one), but I have seen mixed results on all. I had to take my antenna down for termite tenting, so before I put it back up, I want to plan (e.g. old guys on 2 story houses - scares the wife). Any recommendations would be helpful.
Four minutes into the video, the Stellar Labs model 30-2435, Outdoor FM Antenna is shown. It is widely available, and could be used as is, just get it as high off the ground as you can. A simple Google search for that antenna yielded numerous sources and prices from ~$19 to $45. This antenna has the F-Connector output, and I recommend using RG-6 coaxial cable for it's low loss.
There are two recommendations- 1) determine if you want a rotating antenna to go to great distances to get stations or not, and depending that answer, if you want the greatest distance, get a rotor. If only local stations are of interest, the vertical dipole is easy !!
I took the cheap T wire antenna that came with the tuner and cut each leg to 29 inches then stripped both ends of each leg and twisted them together to make a 59 inch folded dipole tuned to 98mhz. I then mounted it vertically in my attic and made sure the center conductor of the tuner was connected to the upper leg. I used 300 ohm flat line to connect it directly to the f connector on the back of the tuner without any chokes or baluns and it pulls in anything within 60 miles crystal clear and partial signals from 70-80 miles The folded vertical dipole works great and has a lower noise floor than a standard dipole . I only had 3-1/2 feet of space in my attic so I drilled a 1" hole in one of the wall top plates and dropped a foot or so of the bottom leg down it to keep everything straight and vertical. As far as omni directional goes you cannot buy a better antenna
Thank you very much for your fine comments ! Your use of the "twinlead" antenna is a very good one !! Be sure to have the leads from the dipole to the tuner slightly twisted to have better noise rejection as could be picked up by that portion of the antenna system.
I'm wondering if the cheap T wire antenna that comes with tuners is already "folded". As far as I can tell, based on continuity measurements this seems to be the case.
When I lived in north east Missouri in the late 80’s I had a radio shack tv antenna on the roof and got weak stations 300 miles away now in north west Houston Texas I can’t get a station 15 miles away on antenna is there signal boosters available that will help with digital- ,analog always came in but week
I would like to find a source for the antenna you started speaking of at 4:59 in the video. I've been looking for a good antenna to mount in the attic. BTW, thanks for posting.
The Stellar Labs 30-2435 can be purchased at www.newark.com/stellar-labs/30-2435/outdoor-omnidirectional-fm-antenna/dp/55W7744?mckv=sLjrascK4_dc|pcrid||plid||kword|30-2435|match|p|slid||product||pgrid|1235851176204666|ptaid|kwd-77240787909419:loc-190|&s_kwcid=AL!8472!3!!p!!o!!30-2435&msclkid=ed80094ce26411b2557b56717e4fea6e&CMP=KNC-BUSA-GEN-SKU-Electrical for $12.04 + tax, shipping/handling
When a folded dipole antenna is horizontal, the polar pattern is a figure 8 with the greatest sensitivity is perpendicular to the antenna and the least sensitivity in the direction that the ends of the antenna are pointing. When the folded dipole is vertical, the polar pattern is circular, with equal reception sensitivity in all directions.
Unfortunate the cheap stock wire antenna was discounted and not tested. Even a guy sitting there asked. Knowing if the test results were negligible or drasticly better would be very helpful in deciding to spend the ~$20 on a better antenna or just using what came in the box. Next question is- Would reception of stock wire antenna results be better with leads verticle (one up and one down) same as other antenna was tested instead of hanging horizontal as in video?
If you measure the input capacitance of the FM tuner, and add the capacitance of the coax cable, you will quickly find the cable adds attenuation to the captured FM signal, minimizing the signal into the tuner. By the time you get to and significant height above the tune, there may not be enough signal to be worth anything ! The dipole antenna can provide a better impedance match to the coax cable and the tuner input, maximizing the captured signal into the tuner. The "Perfect" single wire antenna system, as mentioned in the talk, is 31 inches long, fed into a 31 inch piece of coax into the tuner input.
Robert Klacza What kind of coax are you using? Coax loss is dependent upon input frequency and capacitance (I/R) losses between the core and shield. Bigger (diameter) coax typically has less loss. Higher input frequency = more loss for any given coax. I have never seen a dipole at ground level (at VHF/UHF) frequencies perform better than a well "fed" antenna in an attic. The old adage "Height makes might" for VHF/UHF always holds. In the end, get that antenna up! PS - thumbs up on both your videos!
Let me add.....True circular polarized transmissions have equal power in both the V and H planes. And they transmit with either right (RH), or left hand (LH) circular polarization. The reason they are more immune to multipath is because if we say start with a RH polarized signal, the line of sight signal hits you with a RH polarized signal, however, if any of the transmitter's signal bounces/reflects off of a nearby object, the reflection signal changes the direction of rotation, (meaning in this case where we started of with RH circular, it will come away from the object it reflected off of, being LH). And the receive antenna (being a RH circular design) is immune the LH signal.
Hey Bob!! I liked your video! I made my own 147 cm dipole and it works fine! But it`s not omnidirectional, I need to know the exactly dimentions of de circular antenna because I`d like to make it myself. Sadly ,it is not available to buy to buy in my country. Here in Argentina FM broadcasting signals are horizontal, so putting a vertical dipole for comercial FM does not work.
Thank you for your comments ! It would be interesting for you to take a station quality scan with both horizontal and vertical directions and measure the results !!
Thank you Laura for your nice comment! The SMWTMS meeting where this video was recorded feature Pizza and Beer, and may result in the behavior shown....
I made a few comments here, but I DID want to thank you very much for the idea of orienting a simple dipole vertical. With all my antenna experience in industry, I just did not consider it before - not sure why not. Anyway, I live half way between New York City and Philadelphia, and can receive both well if I use an omni antenna. I bought the folded dipole that was bent into a circle, like the one you showed, and it worked OK, but the vertical folded dipole worked a hair better. I can receive about 85+ stations, and the ones that come in, in stereo, with a rating of 9+ (on a 1-10 scale, 10 being the best) I receive about 60 stations. Thanks for the tip!
Stephan, Thank you very much for your reply, and that you now can receive the great number of listenable stations !! Enjoy your improved reception in this Holiday Season !!!
So complete newby here. Most interesting. I would like to purchase a cheap effective fm antenna. I have a 30' height were my ota anntena is secured. Rec Resideing in southern Ontario. Suggestions ? Anyone
QUESTION FOR ENGENEERS: DOES LENGTH OF CABLE FOR FM MAKE NEGATIVE DIFFERENCE? HOW LONG CAN FM ANTENNA BE AND STIL HAVE SIGNAL WITHOUT SIGNIFICANT DECREASE???
Thank you very much for your insightful question ! A recommended length for the cable is 1/4 wavelength, ~98MHz, is 31 inches. This length gives optimum impedance match with the minimum of loss. Using the data below, rounding off the numbers, 3 feet times 0.02dB/ft = 0.06dB of loss. That is within experimental error... Most quality RF Co-Axial cable manufacturers have a specification for dB loss at a certain frequency per 100 feet of length. Example- Belden 1694A - Coax, RG6 Type, #18 Solid BC, Duofoil® + 95% TC braid, the nominal loss at 100MHz is 1.95 dB per 100 foot length. Please see catalog.belden.com/index.cfm?event=pd&p=PF_1694A I hope that will answer your question. If not, please reply !
@@robertklacza1160 I asked for a MERCEDES and got ROLLS ROYCE of an answer. it has been a pleasure watching the video and reading the answer. Thank you so much.
In the USA, circular polarization is the most used, but in other countries in Europe, vertical only may be the choice, based on feedback from Poland and other European countries........
Basically, for FM, 31 inches vertical is the target, with as big a sheet metal ground plane as possible, like in the middle of the roof, but the styling folks don't like that... for AM, the longer the better, like the old CB radio masts attached to the metal bumpers, on cars with such a thing... Trucks are more likely to have real metal bumpers now !
Hey Bob, great information! A few years ago, I took a dipole driven element off an old TV antenna, and used some of the old ch 2-6 elements to make the poles closer to the FM band, then cut them to 98 MHz, and mounted it vertically on a horizontal stand off well below my current Winegard TV antenna. For some stupid reason, I used a 4:1 balun, as I can only assume I was thinking of the impedance of the folded dipole antenna. I've since removed the balun, and noticed a little improvement in reception; but, I'm really intrigued about using a folded dipole (and 4:1 balun) for the increased bandwidth it's supposed to deliver over the standard stick dipole. Do you think it would be significant? The Stellar Labs 360 seems like a low cost to experiment with, but I'm wondering about the total length of it when the curved poles are straightened out. From what I can find, it seems like it's a bit short, and may favor the upper part of the FM band. Is there any way you can measure the antenna, and post what the total length of it would be, straightened out? If it's a bit short, Stellar Labs makes a yagi with a folded dipole driven element that is a bit more, but may be more tuned to the center of the band. Anyway, thanks again for the great info, and I hope to see a future video on AM antenna systems (like why an FM vertical works so much better on the car radio to pick up AM stations than any AM loop antenna I've tried for my Sangean in my camper, and how I can make something that's omni-directional, external, for AM, and that'll work as good as what's on the car... and I know the impedance is an issue, too...). Thanks!
The Stellar Labs 30-2435 antenna, when straightened out, is a bit less than 55", so it would definitely favor the high end of the FM band, and have poorer reception at the low end of the band... AM loop antennas need to be large in order to be more effective in signal pickup. Thank you very much for your reply !!
Antenna modelling demonstrates that by using a stick / open dipole connected to a 4:1 balun, actually increases bandwidth coverage compared to a folded dipole. The forward gain is not quite as high because of the intentional impedance mismatch. I would never use that type of dipole setup at 87 to 108 MHz. Instead, I use a horizontally polarised 8-element FM Yagi. But for ~ 25 to 60 MHz DX, a 4 metre total length horizontally polarised 'stick' dipole + 4:1 (300/75-Ohm) balun + RG6 coax setup is quite effective for domestic and overseas ionospheric DX.
Hi Bob Klacza. I'm Ben Coleman from Brisbane, Australia. after watching this video so helpful but I'm trying to get a radio station that isn't streaming online yet called 100.9 ZZZ FM Lismore. How do I get the station from my household which my place to the station in length is 126.35km in a straight line.
Thank you for your interesting comment and reception condition. You would need a solution as given by Tim Mack, Stacked Yagi antennas on a 70' tower were my only option. I would suggest if you are going into that amount of effort, that you consider a rotor so you can get everything !!!!
Sadly long out of production, but the BIC "Beam Box", basically a *selectable/ tuneable* Yagi in an enclosure the size of a small phonograph or turntable, has worked very well for me and a few of my friends back when we lived in apartments in areas with generally lousy FM reception and where outside or attic antennas were not allowed. Lower signal output than you'd get from a dipole (for one friend of mine, adding a signal booster between the Beam Box and the receiver made a huge improvement), but the selectable elements and bandbass filtering means that you can often greatly reduce or eliminate interference from adjacent stations. The FM-8 was the plain-Jane, 300 ohm version, the FM-10 was prettier, with smoked plexiglas top, and had a 75 ohm output as well. Last time I looked, these were fetching a hundred bucks or so on Ebay. If you cannot put up an outside or attic antenna, then the Beam Box is probably worth the money. FWIW, I live in hilly New England, and I only listen to low-power college and public radio on the left end of the dial.
Thank you for your interesting comment. Manually tuning the antenna with additional knobs can optimize reception. Prices for this product on eBay range from mid $30's to $150 as shown on 04/14/2020.
Thank you very much! I am erecting a multi-antenna mast and I now know how to address the fm band. Has anyone ever tested a multi-band discone antenna on the fm band? I am also curious to see how it receive UHF tv. That one is going on top. Merci VA3KPG
Bob, great video. Read through most of the comments and replies. Enlightening. My situation is that I have a metal roof on my house that interferes with FM reception. I saw Alan Nyhius' question and your reply below suggesting to put a vertical dipole about 1 m from the house on the side where the station's transmitter is located. I assume attic with metal roof would not be good. Should I try to put vertical dipole about 1m from house?. I only want to listen to one station and it is a repeated NPR station with antenna 5.7 miles away with power of 0.08kW (The FCC card says it is vertically polarized if I am reading it correctly). I have an old Zenith MC7030 receiver/tuner with the screws for 300 ohm antenna, no coax input. Should I use an adapter from screws to coax?, or should I use another type of wire to string out to the north side which will be about 45' away from receiver where metal roof comes down and ends? It is a gable roof and I could locate antenna at eaves or lower. Eaves are high, about 21' off ground (House on pilings). Thanks!
William, Thank you very much for your reply and question ! Since you have a radio with only a 300 Ohm input, I would attach a vertical dipole with "300 Ohm Twin-lead" from the antenna to the receiver, which will result in the minimum loss result ! The cost will be at a minimum as well..... Please reply with your result !!!!
@@robertklacza1160 Hi Bob, well I finally found a decent dipole antenna for sale. It took some doing. I really didnt want to have to mess around uncircling that one you showed on the video. Here is the link to the one I found. Ordered it today, will let you know how it performs. centerfireantenna.com/fm-band-outdoor-dipole-antenna/ Best, Jack
Great video, good info. Just one thought. You mentioned circular polarization, and stated that it helps with minimizing multi-path interference. Well, it does - except - for that to happen you have to receive with a circular polarized antenna. Circular polarized broadcasts have the advantage that you can orientate the receiving antenna in any polarity and still receive the signal - However - either V, or H polarity of receive antenna (using only either of those), will be 3 dB down from that of what one would get if they used a circular polarized antenna for receive.
@@robertklacza1160 Good point, however I believe what I was addressing is the issue of multi-path. The advantage to true circular is that when a signal bounces off of anything, it reverses the circular direction. The original signal may be left, OR right hand circular, and when you receive with the respective direction antenna (let's say it's transmitted with "left hand", and you have a left hand antenna), the right hand signals are rejected, therefore the "multi-path" signals are rejected. You see - any "reflected" signals come in with the opposite direction or rotation, because it flips when it hits an object, and bounces off (in this case, the reflected signals would be right hand). Your left hand receive antenna - would reject them. So, since we are NOT receiving with a circular polarized antenna (that rejects the opposite circular direction), how can we gain multi-path rejection improvement? My understanding is the main reason they transmit with both polarities, is simply because homes use horizontal mounted antennas, and cars use vertical oriented ones. Please share if you feel I missed something, OK? .
@@stephenbay9564 Thank you very much for your added discussion on the circular polarization topic! You have covered the circular polarization topic quite thoroughly!!
I am new to radios just today I have started my project antenna for my sw radio think in fm there are not many that I could pick but after watching this man be I should give fm as well a try. Can some tell me in India will they block fm stations broadcasts from a city to another city?
Thank you for your comment ! There is really no way, once an FM broadcast signal leaves the broadcast antenna, to "Block" it, but only can have an "Interfering" signal to mask the desired one. The way to get better reception from stations in another city is to use a "Yagi Beam" antenna, which is directional in coverage, and should be used with a rotator motor to turn the antenna to the desired city location. Please let me know if you need additional help in achieving your desired result !!
A little clarification. The folded dipoles described in my last comment each had about 288 ohms at resonance. Using the RG62 raised the impedance of each antenna to 1200 ohms. Connecting each antenna to each other lowered the total impedance to 293 ohms at a resonant frequency of 98Mhz (the exact middle of the North American FM broadcast band).
Bob, thanks for the nice video and education. I want to make my own long range folded dipole FM antenna to cover 90 to 108 MHz stations. I understand that on horizontal it works as dipole whereas in vertical it is a "kind" of omnidirectional, correct? What should be the length of the aluminum dipole on each sides when I put in vertical position? Does the formula 468 divided by the frequency works for the vertical position as well?
The length of the dipole is the same regardless of the vertical/horizontal orientation. Wavelength of the frequency is the same both ways. The article at www.kb6nu.com/468-ham-radios-magic-number/ cites the 468 number.
My FM radio has a single wire coming out of it. With the coaxial cable there are two wires - which of the two coaxial cables is connected to the single radio wire?
You have, unfortunately, no choice in this due to the fact there is only one wire. Make sure that the wire is about 31" long, and put it straight up in the air ! In order to use a coaxial cable, the internal circuitry of the radio would have to be redesigned.....
The length for the main pick up dipole is again in the neighborhood of 62" end to end. I measured my old 8 element Yagi beam FM antenna, that I believe is a Winegard brand, with the following results- the two pickup dipoles were different, the rear dipole was about 62" tip to tip, the leading dipole was about 53" tip to tip. The single reflector element being longer at 66" tip to tip, and the leading five director elements are all about 49" tip to tip. The total length of the pipe is 94", or very nearly eight feet !! I hope that helps...
The Stellar Labs 30-2435 can be purchased at www.newark.com/stellar-labs/30-2435/outdoor-omnidirectional-fm-antenna/dp/55W7744?mckv=sLjrascK4_dc|pcrid||plid||kword|30-2435|match|p|slid||product||pgrid|1235851176204666|ptaid|kwd-77240787909419:loc-190|&s_kwcid=AL!8472!3!!p!!o!!30-2435&msclkid=ed80094ce26411b2557b56717e4fea6e&CMP=KNC-BUSA-GEN-SKU-Electrical for $12.04 + tax+ Shipping/handling !
American English- Thanks for sharing this information, almost nobody touches this type of topic. Greetings from Mexico. Beno, Thank you very much for your comment! Please share this video with others who are interested in good FM reception !!
The simple twin-lead dipole can work well, as long as the dipole is vertcal, and the twin-lead feed line to the radio is horizontal and twisted with one twist every 8 to 10 inches to avoid picking up noise....
@@robertklacza1160 Today is February 12, 2021. I just now discovered your reply back to me. Thank you very much. I have watched this video many times. It is great & to the point.
Can someone tell me what are the components of the fm antenna? A trap? I am restoring an old tube radio and it has a loop in the back of the console but I want to upgrade that to something much better. the whole 75ohm vs 300 ohm thing is a mystery to me also. when I bought my house there was an old big tv antenna not being used... can I just run a coax cable from that thing? thx!!
Dear Mr. Jam, Most of the time on old tube radios, the "Loop" antenna is used for AM pickup from 540KHz to 1600 KHz. The tan color T-shaped FM antenna made of twinlead in the background of the video is the standard 300 Ohm antenna that will connect with the "300 Ohm" inputs on FM receivers. The 75 Ohm input on FM receivers is sometimes one of the 300 Ohm inputs, with the 75 Ohm coaxial cable shield going to chassis ground. The TV antenna that you inherited could be used for FM, even though it may not be optimized for FM. It will be far higher elevation above ground, and be able to provide a greater FM signal pickup from the airwaves. To answer your question, the components of this FM antenna consists of a "dipole" conductive metal tubing bent into a flattened loop, a matching transformer, to change the "Balanced" dipole pickup into a single ended coaxial cable feed, and the feed cable itself from the transformer to the receiver. Please let me know if that answers your question. You may want to listen to the descriptions in the video to gain a better understanding of antenna terminology. Best regards....
The antenna in the video is sized for best reception at 98 MHZ. 98/433 = ~0 .226, so multiply all above dimensions by 0.226, for example, 31" times .226 = ~ 7" Go from there !! Check some Radio Amateur handbooks for more ideas !!
The argument that there are FM stations transmitting in circular polarisation seems to be correct only for United States. In Europe, e.g. Poland there is NO circular polarisation in use. We have H and V stations ONLY, because of interference and bandwidth availability in adjacent areas. So - vertical dipole won't work in H (it would somehow, but its gain is gonna be marginal). This strategy causes some problems with multi-path in cities, but results with greater number of station allowed to transmit. So its in fact a win-win situation.
Thank you for your clarification of FM broadcasting in Europe and specifically Poland ! Multipath effects in FM reception is most prevalent in moving vehicles, but can happen in a home situation, but in this case moving the antenna to a different location may solve this issue.
tom jackson I live in northwestern Houston Texas were can I get a killer antenna for my HD-20 sangean my HDRadio in my VW gets better and more stations on HD than the home receiver in HD!
Bob, is there a way to tune out adjacent channel bleedover on certain stations with an FM antenna? I've used rabbit ears, and an outdoor antenna. I live 20 miles from a station I like to listen to, and it gets adjacent channel bleedover from 3 stations in between the one station from time to time.
That could possibly be done with a multi-element Yagi type antenna, with a rotor to point it in the right direction, providing the unwanted station is ~ 90 degrees from the desired station. The other way to get rid of adjacent frequency stations is to get a modern FM tuner with DSP front end IC's from NXP, TI or STM. The NXP chip set is used in the Sony XDR-F1, and works quite well, but unfortunately is out of production. eBay has some available, but the prices for these reach into the stratosphere.....
I don't have that problem anymore. I now have a Sangean WR-2 radio it it gets great reception with the rabbit ears and the outdoor antenna. I don't have a yagi type antenna, but I do have a GE Jasco indoor/outdoor attic antenna that I use for tv and fm radio and it seems to work very good for an fm antenna.
I have a sangean radio in the garage and kenwood kt-7500 tuner inside house that I listen to. I have a basic rca rabbit ears antenna that I use for both and get good reception. A few weeks ago I was trying to listen to an fm station with Sangean in the garage that was 175-200 miles away and was barely listenable. I accidentally pushed one of the rabbit ear antennas down next to a 5' tall steel hand-truck and the signal strength went up so high it came in stereo! I tested this with my Kenwood tuner in narrow band and signal increased from 1.5 to 3.0-3.25, or basically double. So the vertical 5' antenna with enough metal mass does work great. I got a couple 8' steel pipes, stood them up about 2 feet apart and connected a thick speaker wire across to them, and then put the rabbit ears next to it. Signal went up only slightly higher, a solid 3.25. I tried with taller pipes but it didn't improve any. So it appears that a 6 - 7' tall metal antenna is about as good as it gets for FM signal.
@@SMWTMS Hmmm, I'm going to have to play around with that. I don't care much for the stations around in the 60 mile range, but I still don't want a roof mount antenna.
The cost of this antenna is about $20. A 6 element Yagi antenna and rotor can cost ten times as much... The complexity and size do give you better reception, but not many will step up to the cost and complexity
We learned that all of the antennas perform about the same, but there was a slight difference, that being the vertical orientation is omni-directional.
Thanks for your efforts Bob. At the end of the video you mention a segway in to part two. Was this not shared? Also, if I put an omni-directional (like the round one) or a bi-directional (like the "plus sign" shaped one) in my attic how does the length of the coax cable affect signal strength and will a powered signal booster help?
The segway was into the comparison of the Sony and Sangean AM/FM HD tuners. Please see it at my "Sangean HDT-20 vs Sony XDR-F1" TH-cam video. The coax cables have some attenuation at FM frequencies, a couple of dB per 100 feet, depending on brand and type. I recommend RG-6 by a name brand manufacturer.
I remember as a boy AM had alot of static space on the band I would pick up many faraway stations at night CBC back then would go off the air and NeW Orleans would come in . CBS radio mystery theater if you remember that program with EG Marshall when the program would fade out you heard a mystec sound effect to the program when hearing the static.
I'm 35 and I never knew this niche hobby exists. I acciddntally found this video as I was looking for antenna building tutorial for my old Pioneer kp500 car stereo. That unit is a super tuner az they say but I don't know what that means lol.
The Pioneer "Supertuner" aftermarket car stereos made attempts to minimize the effects of multi-path distortion on FM reception. Some friends said the OEM car radio was better !!
So the 2 take aways here are that dipole antennas are good but should be mounted vertical for FM. I thought terrestrial noise bouncing off vertical structures such as power poles, trees, buildings caused a problem, or maybe is it just negligible?
"Multi-path" reflected signals happen quite often in moving vehicle receivers, but not so much with fixed home installations. With that said, if you tune to a particular local FM station, and the signal is distorted, move the antenna around the room and 9 times out of 10, the poor reception will clear up. Of course, keep the antenna as high off the ground as possible.....
Interesting Video Bob. I have an issue in my new home and I am not a very well versed electronics guy. Have been trying to get FM reception in my shop building on an old Nikko am fm receiver. FM Reception is horrible with a great deal of static. AM reception no problem. The shop is one of those corrugated metal buildings, roof and sides. I tried inside with that "winegard" hd 6010s I think you were displaying in the video and it produced no improvement. Is the shop shielding any FM reception and do I need to go outside with an antenna? I then worry about grounding issues if I go that route. thanks for any help !!
I would suggest putting a vertical dipole outside a window mounted maybe 1 meter from outside of the structure. Choose the side that faces the most of the FM transmitter antennas that you wish to receive.
Very informative video. But it's incorrect to say that all FM Broadcast stations transmit with circular polarization. Here in Canada, most low power stations (under 3 kW) are usually vertical-only polarization. For example, CINQ 102.3 FM.
Dimitri, thank you for your comment ! Yes, Low Power FM's typically don't have the money or space for a circular broadcast antenna, so vertical is the least costly solution for them !!
Coaxial dipole antennas (Flowerpot antenna) are cheap, easy to build and have omnidirectional performance, my airband specific variant works very well on FM broadcast 👍
I have a Magnum Dynalab verical from the 90's in the attic, and want to run a 100 ft coax down to the basement, F type connectors both ends, what coax should I use? 50 ohm or 75?
Looking at the installation guide of the Magnum Dynalab verical antenna, it looks to be a single 1/4 wavelength mast, with no ground plane at it's base. Adding a ground plane at the base with the mast vertical above the ground plane will increase (double) the captured signal strength. The recommended ground plane would be approximately 2 meters by 2 meters with the mast in the center. If the vertical height is available, going to the folded dipole shown will have the same signal strength pickup, but without going through the trouble, size, and expense of the ground plane. I would be interested in hearing from you on your results.
This is the best video I have seen on the subject at hand. Well done.
Thank your so very much for your great comment !! 👍
Thanks for this video, helped me select a home FM antenna which is a largely ignored product in today's digital streaming world.
Thank you for your nice comment ! I am glad that you selected the best FM Antenna for your specific application !!
Thank You for sharing this information i love Radio. Good to see Radio lover's talking about FM antenna.
Thank you very much for your comment !
Very glad to know such a group exists. Thanks for sharing informative content! Wish you all good health and long life!
Thank you very much for your reply ! I sincerely appreciate it !!!
I am a licenced Radio Amateur and should be aware of the majority of this information. However I found it very interesting and enlightening, thank you for the presentation mate!
Thank you very much for your comment !!
Brilliant conference... greetings from Montevideo, Uruguay...!!!
Hernan, thank you very much for your positive comment !
Those goofy T-wires provided with the purchase of a receiver work fine for most people in or near urban areas looking to get only a couple of favorite channels, which is most people in the country now. We who live in rural areas appreciate your information to help us getting those distant broadcasts.
The T-wire antenna can also be arranged with the top of the T vertical, and try to have it up as high as possible. It may be of benefit to add an extension to the twin lead to gain that height.
Thank you for your advice about a whip antenna, and about what its optimal length should be. I have a Sony receiver with a 75 ohm coaxial connection. I found a 30-inch (75 cm) whip antenna with a 30 inch cord, and it works perfectly ... no amplifier needed! I propped it up in a window with a venetian blind, and I now get great reception of an FM station I like, that is 60 miles away! A cheap and very effective solution ... thank you!
Thank you for your very nice comments !!
I'll try that too. No ground plain required?
@@gioscervelo I would be interested in hearing from you if you added a ground plane. The ground plane should be at least 30" in a radius at the base of the vertical antenna and attached to the shield braid of the coaxial cable.
I learned more about FM in this video than trying to research it on my own in years. Thank you Bob for your knowledge I am going to have to try your methods. The higher the antenna the better the signal, so true. DXing is awesome.
Thank you very much for your nice reply !
I mounted four of these folded dipoles vertically and used RG62, 93 ohm cable with a balun at each antenna. I used a spectrum analyzer to phase each antenna and use the correct length of RG62 to raise the impedance of each antenna to 3oo ohms unbalanced. When the antennas were connected together, the unbalance impedance became 75 ohms. Since the FM broadcast band is rather narrow, I could easily phase the antennas Outstanding reception!
Patrick, wow, you really took the bull by the horns and wrestled it into submission! It is not likely that most have access to a spectrum analyzer to handle such a job, or the patience to do it. Congratulations on your fine work and results!!
I'm 32 and i would had loved to be in that room. Thanks for the demo.
Thank you so very much for your comment !!! I appreciate your comment !
same here!!
Nice, indeed 👍
I just thought about building a radio antenna at my property in Park county, Co., was sitting at Chatfield reservoir listening to am radio, thought "this is quaint, I like AM radio" then the lightbulb went off, I could erect an antenna and get really good radio signal up there, long story long, found Bob here explaining proper signal capture and antenna positioning and he's is an engineer so he knows his stuff, thanks Bob!
Thank you very much for your positive comments !!
I'm in Canon and trying to get hippie radio from Poncha with some reliability.
thank god for youtube i was looking for stuff like this explained easy
Thank you for your kind comment !!
Thanks for sharing such an interesting video. I am from Cuba and I always was a FM band lover. I had several antennas to "catch" radio stations from Florida and one of my favorites was a
7-element yagi, along with a
3-step booster which I put right on the mast about 1 foot from the dipole. It was sealed and protected from rain. Oh man! That setup worked like a charm!!!
Power supply was down by the tuner and I used the same 75 ohm coaxial cable to power up the Booster. Amazing guys! I wonder how many stations I'd get here with such a system!!! Okay, thanks again and till your next video.
Thank you very much for your antenna investigations and results!
@@robertklacza1160 Thanks for answering! Stay Safe!
Bob: Thank you for this video. Couple questions: 1) Where can I purchase a folded dipole antenna for FM radio reception? 2) I plan to mount it on my TV antenna mast. My TV antenna is a "Televes 148883 Antenna Ellipse Mix ". 2) Where on the mast, relative to the TV antenna, should I mount the FM dipole. Many thanks. Jim King, Saratoga County, NY
Jim, the easiest and most readily available is the circular Stellar Labs model 30-2435, Outdoor FM Antenna, and just straighten it out. Do a search for the lowest price, generally in the $20 to $30 dollar range. It is 55" when straightened, so it may have a bit less sensitivity at the low end of the FM band, but the higher band will be a bit better !! I would recommend that the vertical FM dipole be mounted below the TV antenna, and that the top of the FM dipole be below the lowest element of the TV antenna. Please update with your results !
Where could you purchase an Antenna like the one shown at the 2:15 mark in this video? Is there any videos on TH-cam that shows how to make one?
The easiest and most readily available is the circular Stellar Labs model 30-2435, Outdoor FM Antenna, and just straighten it out. Do a search for the lowest price, generally in the $20 to $30 dollar range. It is 55" when straightened, so it may have a bit less sensitivity at the low end of the FM band, but the higher band will be a bit better !!
Excellent video. Props to the video editor.
Thank you.
Was having problem with my Denon receiver, in terms of signal. Now I shall try the vertical antenna. May be signals improve. Thanks.
You are very welcome ! Please see th-cam.com/video/fbudkK9LzWY/w-d-xo.html for a comparison of two FM HD tuners, in the case the Dennon receiver tuner has poor reception...
Did this improve your reception?
Excellent, very informative, thanks much!
Thank you very much for your descriptive reply !!
Nice video! Thanks very much! Didn't know that circular polarization was pretty much standard.
Stove-Pipe Dipole
Armed with that information about circular polarization, I built a dipole out of two pieces of 8" (trade size) / 7" (actual size) galvanized HVAC duct. Each arm of the dipole is 690mm or a bit over 27" each. I put a 1" space between the ends where the 75 Ohm CATV cable connects. I did not use a balun of any sort, as the two pieces of stove-pipe make a very good match to 75 Ohms at the middle of the FM band, and I was not too concerned about disruption of the pattern because of feed line currents. Because of the large 7" diameter of the stovepipe, the antenna is fairly broad band.
The antenna seems to work well. I have made some measurements like those you give in your video, so far just for the stovepipe dipole (which I hung vertically in my attic and connected via 75 Ohm CATV cable to my radio in the basement). Have not yet made measurements on other antennas on hand.
Noise in FM Broadcast Reception
This was all in an effort to clean up some "steam" or "scratchiness" that seems to be always present in music received through this radio. I am a bit perplexed how to get rid of it. Even though my radio shows a good strong signal (as I assessed by measuring the voltage at the S-meter output of the FM IF chip), I still hear some scratch in the music. Do I not have a strong enough signal? Perhaps the scratchiness is because of the demodulation method used in the radio? The radio, by the way, is a Kenwood KR-A46 AM-FM stereo receiver., about 1987 vintage. It is frequency synthesizer-controlled, and I have not attempted to align it, though I do have the factory service manual that describes the alignment procedure. I just picked it up at a thrift store recently, so I don't have a great deal of experience with it. Maybe a fully analog FM receiver would have less "scratch"?
Thanks again for the very informative video. Good engineering!
Max
Thank you for your comments ! It is noteworthy that this video urged you on to try building a similar vertical dipole !! With that said, I would suggest that you try a new FM tuner that uses a NXP, STM, or TI digital FM/AM HD chipset. These new tuners can be had for around $200, and if you look at th-cam.com/video/fbudkK9LzWY/w-d-xo.html for the comparison of two of these popular tuners, I am sure you by getting one of these will get rid of any background scratchy static !!!
I'm fortunate to live in a signal-rich urban area and pull strong signals with just an old 300-ohm floppy dipole strip, which I reposition, depending upon atmospheric conditions. That, and a receiver with a good FM stage, has served me well these past 60 years. Our village is the western-most portion of San Diego suburbs and it's a straight shot up the coast to the high antennas sited in the mountains east of the Los Angeles Basin. As I am 400 feet from the Pacific, there is virtually no multi-path phenomenon, because I am sticking out from the continent enough to allow line-of-sight between my cheapo dipole ribbon and the transmitters high atop the coast range of mountains to the north. So I get good signal strength and quite a bit of separation, even though it's almost 100 miles between us! My Fisher receiver, circa 1978, was made with Avery Fisher's patents in Japan and has one of the best FM stages I've encountered, but my two Marantz receivers were equally as good, too. This gear benefitted from American know-how and Japanese expertise in manufacture. I believe that accounts for the popularity of the big super-receivers of the 1970s today. They offer enough stable power to drive even an inefficient speaker system and great FM reception, too. I found no superiority in my high-end Tandberg separate components with their miles of interconnecting cables which may or may not have been picking up RF signals, given the traffic density here. I know it sound like heresy, but I think receivers with their short coupling paths between sections result in a cleaner signal than individual amp-preamp-tuner arrays and all the potential corrosion effects at contact points in this marine (saline) environment. At least it provides less chance of tripping over yards of cables and neatens up your listening area. Wives and sweethearts like the sound, but often balk at the hardware scattered about. I first dropped a needle on a record in 1940, so I've been around the platter several million times! Thanks, Robert, for a thoroughly professional and useful presentation. My brother Jimmy was Chief Plant Engineer for Pacific Bell here and had 12 patents of his assigned to AT&T over the years, so I have some experience with your area of expertise.
Thank you very much for your detailed description of your reception conditions ! You are truly very lucky to be in the situation you are in !! Thank you for your kind comments on my presentation !!!
Thanks, just what i was looking for to get my new HD kenwood radio to stay locked in, Im gonna check on the round one.
When you get some results, please post them here !!
Fantastic video. Thank you very much.
You are very welcome for your nice reply !
The turnstile antenna mentioned at 3:00 and again at 10:40 can be made to work more-or-less omnidirectionally if the section of twin lead connecting the two crossed elements is 1/4 wavelength long. At 98 Mhz this would be about 28". It's called phase-quadrature. It works - the reception pattern is a cloverleaf. The length shown on the vid appears to be random. These things can be pretty frequency-critical.
Rick, thank you for your comment ! Yes, you are correct, but I was advising for an omnidirectional reception pattern that the single dipole yields ! The cloverleaf has four nulls....
I live in a very remote, fringe area. Stacked yagis on a 70' antenna tower were my only option.
Tim, you are absolutely correct !!!
So at 9:46 in the video, the relatively simple dipole id the most feasible and best in its class. So where do you get one? Thank you.
The easiest and most readily available is the circular Stellar Labs model 30-2435, Outdoor FM Antenna, and just straighten it out. Do a search for the lowest price, generally in the $20 to $30 dollar range. It is 55" when straightened, so it may have a bit less sensitivity at the low end of the FM band, but the higher band will be a bit better !!
Very informative! After watching this video I went home and straightened the elements on the Stellar Labs 30-2435 "round dipole" that's been sitting in my basement, unused. I also flipped the mast mounting bracket on the center support and slid it to the far end so it can be easily mounted to a mast, offset at a right angle. Mounted in this configuration I assume the built-in transformer will be more susceptible to water intrusion, so I will bypassing it and using a pigtail balun.
Thank you very much for your reply !!
Two more steps in complexity, for another 6dB gain, would be to have two vertical dipoles end-to-end with a shorted quarter-wave stub between them. I used that for pirate broadcasting long ago. It worked very well. The impedance around the middle of the stub is 200Ω balanced. If you use a half wavelength (times whatever the velocity factor is) of 52Ω coax to make a balun to feed it there, it works out perfectly.
That is a good suggestion, but some people may not have the readily available height to use that technique. Thank you very much for your reply and good suggestion !!
Great video! I have a number of high quality component FM tuners fed by a variety of antenna systems in different rooms of my house: Horizontal folded dipole, vertical dipole, and my garage tuner has two yagis facing west (to Cleveland, Ohio) and south (to Kent, Ohio), switched to provide the best tuner input. We live low in the valley of the Chagrin River so FM reception is...challenging.
Thank you for your comments about optimizing FM reception under difficult conditions !
I've got. 50 years in the radio business, with 20 years installing FM / TV antennas. Even though I have FIOS, I still have antennas on my roof. I get better quality HDTV off my antennas than I do with Fios. Just recently I've been experimenting with an out door FM antenna and found this information very useful. The first thing intone morning I will flip my folded dipole to the vertical position as you advise. I'm looking forward to good results and will,let your know. I forgot all about the circular orientation of FM. I am anxious for good results. If you want to know something about radio ask a Ham!
Thank you very much for your kind comments! Please post your results!! I look forward for your feedback!!!
Where can I purchase the single T straight antenna that you liked? I'm having a hard time finding one that isn't several hundred dollars.
The easiest and most readily available is the circular Stellar Labs model 30-2435, Outdoor FM Antenna, and just straighten it out. Do a search for the lowest price, generally in the $20 to $30 dollar range. It is 55" when straightened, so it may have a bit less sensitivity at the low end of the FM band, but the higher band will be a bit better !!
Thank you for your reply. I don't know why I wasn't notified of it. By dumb luck I ended up getting a windstorm damaged Stellar Labs 30-2460 a coworker was going to trash for nothing. I took out the part that looks like a folded dipole. Unlike the Stellar Labs 30-2435 it is one piece. I like that.
I straightened it out the best I could and hooked 300 ohm 18awg ladder line to it, then ran the ladder line directly to my vintage receivers 300 ohm antenna connection points. I now have the best reception I can remember.
I'm thinking of duplicating this antenna with 3/8 or 1/2 inch OD copper tubing to see if there's any gains to be had from the copper construction.
Thanks for pointing these designs out.
Dear sir, thank you for the information shared. I am also a FM lover from mumbai, India.
Thank you very much for your kind comment !!
I appreciate the video. The TH-cam might have been an adder to what you were doing there and understanding you will possibly concentrating more on a primary plan But I wish you would have got more into the yagi question being you only did the one video I think and there's not much else out here. Again thank you so much that you did the video in the first place..! was glad I was able to re-watch it to remember the vertical Mount idea. Apparently no one is in my shoes at all, are the number of us is so small that it might as well be Z-Ro because search engines send us nowhere. It seems like no one wants to bring in one station for dear life and it's unheard of for anyone to even try if it's over 70 MI. Humbug I only can receive one station that plays any kind of music that I like to hear. We receive kfzx from no trees, Texas (Gardendale but west of ) and pick it up in Marfa, Texas we're probably 200 mi from Gardendale Texas by road,but the station transmitter Tower is 130 MI by flight. I have a picture of my ZR2 setting in front of it. The usual 100,000 Watts
102.1 been classic rock for at least 20 years but now there's a bit of 80s touch added in the calling it The eagle.
It's Received on a discone 21' off the ground at 4,725' elev
From 130 mi away! No Trees Texas is a high spot maybe 20 miles north west of Odessa. I had it hooked up to a yagi for a little bit and it did not do well at all but I had it horizontal and I think that was a huge mistake..? But I'm thinking now mostly I might have had a coax issue as well. More testing the discone is centered by a 54 mag wideband hf54 Diamond d130nj
Which would apparently be a very good FM antenna for Omni work and maybe a little tuning would kick it off very well.. notch filter and I'm also imagining most would say the discount would just bring in way too much noise of all other frequencies. Don't use it and maybe don't need the notch..
I wonder if a marine antenna 60inch would work indoor for FM radio reception.
Any antenna is better than nothing, but the marine band is in the frequency range between 156 and 174 MHz, and will not be optimized for the FM band of 88 to 108 MHz.
I use a vertical half wave for FM. Works great.
Thank you for your comment !!
6:05 The ones I've had experience with are called "quasi-circular." Each antenna in the bay is a half-wave dipole, with a difference. Half of each element is a horizontal half circle, with the second half at a right angle to the first, one end pointing up, the other, down
Yes, that is correct. There are several FM and TV broadcast antenna manufacturers, and each have their own patents and copyrights to the ones that they make. It would be interesting to actually plot the polar patterns to measure the effectiveness.
Bob, I'm a novice at this, so I'm working with trial an error. It appears that the length of the antenna arms seems to matter. I've heard 29" and 30" in different videos for making antenna. The aluminum S unit/dipole that is better vertical then horizontal (05:35 in video) is clearly longer then 30" for each arm in the T. Is there a ratio that one tries to use to maximize signal strength reception? Basically, is more metal better then less metal for each arm? Would 60" arms of the T be twice as effective as 30" arms? I'm hooking up to a radio receiver in an apartment/office and there is no access to the attic, roof or above for an FM antenna to be mounted to anything. I stuck with 10 foot ceiling perhaps 20-25 feet of the ground, being on a second story of a two story building. Any thoughts on how to optimize this with out mortgaging the house to do it would be appreciated. Thanks
Chris, thanks for your comments and questions ! The 31" length of each arm in the antenna tunes it to the center of the FM frequency band, 98 MHz. If you make the arms 60", that would optimize the antenna for receiving a 49 MHz frequency. Just locate the antenna as high in elevation as possible, and if you have the desire to prefer only certain FM stations, get their broadcasting antenna location and place your antenna as close to their direction in the building as possible !! Thanks again !!
Newbee here. Can I purchase a good outdoor FM antenna or are there patterns for building one? I do not know how to connect the antenna to the lead going down. I am not even sure where to purchase materials any more as most DYI stores have closed in the area. I have a Channel Master TV antenna on a rotor for TV, but it is only for UHF and my wife sorely misses FM. I can have a second lead coming down for the FM. I have seen some circular and some horizontal flat (e.g. like the Channel Master one), but I have seen mixed results on all. I had to take my antenna down for termite tenting, so before I put it back up, I want to plan (e.g. old guys on 2 story houses - scares the wife). Any recommendations would be helpful.
Four minutes into the video, the Stellar Labs model 30-2435, Outdoor FM Antenna is shown. It is widely available, and could be used as is, just get it as high off the ground as you can. A simple Google search for that antenna yielded numerous sources and prices from ~$19 to $45. This antenna has the F-Connector output, and I recommend using RG-6 coaxial cable for it's low loss.
There are two recommendations- 1) determine if you want a rotating antenna to go to great distances to get stations or not, and depending that answer, if you want the greatest distance, get a rotor. If only local stations are of interest, the vertical dipole is easy !!
I took the cheap T wire antenna that came with the tuner and cut each leg to 29 inches then stripped both ends of each leg and twisted them together to make a 59 inch folded dipole tuned to 98mhz. I then mounted it vertically in my attic and made sure the center conductor of the tuner was connected to the upper leg. I used 300 ohm flat line to connect it directly to the f connector on the back of the tuner without any chokes or baluns and it pulls in anything within 60 miles crystal clear and partial signals from 70-80 miles
The folded vertical dipole works great and has a lower noise floor than a standard dipole . I only had 3-1/2 feet of space in my attic so I drilled a 1" hole in one of the wall top plates and dropped a foot or so of the bottom leg down it to keep everything straight and vertical.
As far as omni directional goes you cannot buy a better antenna
Thank you very much for your fine comments ! Your use of the "twinlead" antenna is a very good one !! Be sure to have the leads from the dipole to the tuner slightly twisted to have better noise rejection as could be picked up by that portion of the antenna system.
I'm wondering if the cheap T wire antenna that comes with tuners is already "folded". As far as I can tell, based on continuity measurements this seems to be the case.
When I lived in north east Missouri in the late 80’s I had a radio shack tv antenna on the roof and got weak stations 300 miles away now in north west Houston Texas I can’t get a station 15 miles away on antenna is there signal boosters available that will help with digital- ,analog always came in but week
Thank you very much for your reply!
I would like to find a source for the antenna you started speaking of at 4:59 in the video. I've been looking for a good antenna to mount in the attic. BTW, thanks for posting.
Just buy the round one and straighten it out.....
The Stellar Labs 30-2435 can be purchased at www.newark.com/stellar-labs/30-2435/outdoor-omnidirectional-fm-antenna/dp/55W7744?mckv=sLjrascK4_dc|pcrid||plid||kword|30-2435|match|p|slid||product||pgrid|1235851176204666|ptaid|kwd-77240787909419:loc-190|&s_kwcid=AL!8472!3!!p!!o!!30-2435&msclkid=ed80094ce26411b2557b56717e4fea6e&CMP=KNC-BUSA-GEN-SKU-Electrical for $12.04 + tax, shipping/handling
Great video, keep it up!🌐
Thank you very much for your comments !!😊
Does a folded dipole FM antenna work when hung vertically? Or only for horizontal mount?
When a folded dipole antenna is horizontal, the polar pattern is a figure 8 with the greatest sensitivity is perpendicular to the antenna and the least sensitivity in the direction that the ends of the antenna are pointing. When the folded dipole is vertical, the polar pattern is circular, with equal reception sensitivity in all directions.
🔥💓🔥 Great video. Great channel. I'm in. Worked great for my radio. 🔥💓🔥
Good to hear from you and your great comment ! Glad it worked for you !!
Unfortunate the cheap stock wire antenna was discounted and not tested. Even a guy sitting there asked. Knowing if the test results were negligible or drasticly better would be very helpful in deciding to spend the ~$20 on a better antenna or just using what came in the box.
Next question is- Would reception of stock wire antenna results be better with leads verticle (one up and one down) same as other antenna was tested instead of hanging horizontal as in video?
If you measure the input capacitance of the FM tuner, and add the capacitance of the coax cable, you will quickly find the cable adds attenuation to the captured FM signal, minimizing the signal into the tuner. By the time you get to and significant height above the tune, there may not be enough signal to be worth anything ! The dipole antenna can provide a better impedance match to the coax cable and the tuner input, maximizing the captured signal into the tuner. The "Perfect" single wire antenna system, as mentioned in the talk, is 31 inches long, fed into a 31 inch piece of coax into the tuner input.
Robert Klacza What kind of coax are you using? Coax loss is dependent upon input frequency and capacitance (I/R) losses between the core and shield. Bigger (diameter) coax typically has less loss. Higher input frequency = more loss for any given coax. I have never seen a dipole at ground level (at VHF/UHF) frequencies perform better than a well "fed" antenna in an attic. The old adage "Height makes might" for VHF/UHF always holds. In the end, get that antenna up! PS - thumbs up on both your videos!
What about taking the "Straight-S" aerial, removing the balun & running 300-ohm twin-lead, instead?
Thanks for your video.
Thank you very much for your reply !!!!
Thank you Raymond for your kind reply !!
Let me add.....True circular polarized transmissions have equal power in both the V and H planes. And they transmit with either right (RH), or left hand (LH) circular polarization. The reason they are more immune to multipath is because if we say start with a RH polarized signal, the line of sight signal hits you with a RH polarized signal, however, if any of the transmitter's signal bounces/reflects off of a nearby object, the reflection signal changes the direction of rotation, (meaning in this case where we started of with RH circular, it will come away from the object it reflected off of, being LH). And the receive antenna (being a RH circular design) is immune the LH signal.
Hey Bob!! I liked your video! I made my own 147 cm dipole and it works fine! But it`s not omnidirectional, I need to know the exactly dimentions of de circular antenna because I`d like to make it myself. Sadly ,it is not available to buy to buy in my country. Here in Argentina FM broadcasting signals are horizontal, so putting a vertical dipole for comercial FM does not work.
Thank you for your comments ! It would be interesting for you to take a station quality scan with both horizontal and vertical directions and measure the results !!
Just awesome. I never would have interrupted.
Thank you Laura for your nice comment! The SMWTMS meeting where this video was recorded feature Pizza and Beer, and may result in the behavior shown....
I made a few comments here, but I DID want to thank you very much for the idea of orienting a simple dipole vertical. With all my antenna experience in industry, I just did not consider it before - not sure why not.
Anyway, I live half way between New York City and Philadelphia, and can receive both well if I use an omni antenna. I bought the folded dipole that was bent into a circle, like the one you showed, and it worked OK, but the vertical folded dipole worked a hair better. I can receive about 85+ stations, and the ones that come in, in stereo, with a rating of 9+ (on a 1-10 scale, 10 being the best) I receive about 60 stations. Thanks for the tip!
Stephan, Thank you very much for your reply, and that you now can receive the great number of listenable stations !! Enjoy your improved reception in this Holiday Season !!!
Stephan, Thank you so very much for your comments !!
this was pretty interesting to watch
Thank you very much !
So complete newby here. Most interesting. I would like to purchase a cheap effective fm antenna. I have a 30' height were my ota anntena is secured. Rec
Resideing in southern Ontario. Suggestions ? Anyone
@@brmelectric Try the round one first, and if you need to go truly omni-directional, straighten it out and hang it vertical !
QUESTION FOR ENGENEERS: DOES LENGTH OF CABLE FOR FM MAKE NEGATIVE DIFFERENCE? HOW LONG CAN FM ANTENNA BE AND STIL HAVE SIGNAL WITHOUT SIGNIFICANT DECREASE???
Thank you very much for your insightful question ! A recommended length for the cable is 1/4 wavelength, ~98MHz, is 31 inches. This length gives optimum impedance match with the minimum of loss. Using the data below, rounding off the numbers, 3 feet times 0.02dB/ft = 0.06dB of loss. That is within experimental error... Most quality RF Co-Axial cable manufacturers have a specification for dB loss at a certain frequency per 100 feet of length. Example- Belden 1694A - Coax, RG6 Type, #18 Solid BC, Duofoil® + 95% TC braid, the nominal loss at 100MHz is 1.95 dB per 100 foot length. Please see catalog.belden.com/index.cfm?event=pd&p=PF_1694A I hope that will answer your question. If not, please reply !
@@robertklacza1160 I asked for a MERCEDES and got ROLLS ROYCE of an answer. it has been a pleasure watching the video and reading the answer. Thank you so much.
what polarization is the most used across world
In the USA, circular polarization is the most used, but in other countries in Europe, vertical only may be the choice, based on feedback from Poland and other European countries........
very good, easy to understand video
Thank you for your kind comment !
I was hoping for more information on automotive fm antenna.
Basically, for FM, 31 inches vertical is the target, with as big a sheet metal ground plane as possible, like in the middle of the roof, but the styling folks don't like that... for AM, the longer the better, like the old CB radio masts attached to the metal bumpers, on cars with such a thing... Trucks are more likely to have real metal bumpers now !
Hey Bob, great information! A few years ago, I took a dipole driven element off an old TV antenna, and used some of the old ch 2-6 elements to make the poles closer to the FM band, then cut them to 98 MHz, and mounted it vertically on a horizontal stand off well below my current Winegard TV antenna. For some stupid reason, I used a 4:1 balun, as I can only assume I was thinking of the impedance of the folded dipole antenna. I've since removed the balun, and noticed a little improvement in reception; but, I'm really intrigued about using a folded dipole (and 4:1 balun) for the increased bandwidth it's supposed to deliver over the standard stick dipole.
Do you think it would be significant? The Stellar Labs 360 seems like a low cost to experiment with, but I'm wondering about the total length of it when the curved poles are straightened out. From what I can find, it seems like it's a bit short, and may favor the upper part of the FM band. Is there any way you can measure the antenna, and post what the total length of it would be, straightened out? If it's a bit short, Stellar Labs makes a yagi with a folded dipole driven element that is a bit more, but may be more tuned to the center of the band.
Anyway, thanks again for the great info, and I hope to see a future video on AM antenna systems (like why an FM vertical works so much better on the car radio to pick up AM stations than any AM loop antenna I've tried for my Sangean in my camper, and how I can make something that's omni-directional, external, for AM, and that'll work as good as what's on the car... and I know the impedance is an issue, too...).
Thanks!
The Stellar Labs 30-2435 antenna, when straightened out, is a bit less than 55", so it would definitely favor the high end of the FM band, and have poorer reception at the low end of the band... AM loop antennas need to be large in order to be more effective in signal pickup. Thank you very much for your reply !!
Antenna modelling demonstrates that by using a stick / open dipole connected to a 4:1 balun, actually increases bandwidth coverage compared to a folded dipole. The forward gain is not quite as high because of the intentional impedance mismatch. I would never use that type of dipole setup at 87 to 108 MHz. Instead, I use a horizontally polarised 8-element FM Yagi. But for ~ 25 to 60 MHz DX, a 4 metre total length horizontally polarised 'stick' dipole + 4:1 (300/75-Ohm) balun + RG6 coax setup is quite effective for domestic and overseas ionospheric DX.
Love this educational video
Thank you very much for your reply !!
Hi Bob Klacza. I'm Ben Coleman from Brisbane, Australia. after watching this video so helpful but I'm trying to get a radio station that isn't streaming online yet called 100.9 ZZZ FM Lismore. How do I get the station from my household which my place to the station in length is 126.35km in a straight line.
Thank you for your interesting comment and reception condition. You would need a solution as given by Tim Mack, Stacked Yagi antennas on a 70' tower were my only option. I would suggest if you are going into that amount of effort, that you consider a rotor so you can get everything !!!!
Nice discussion. Thanks!
Thank you for your nice comment !
Sadly long out of production, but the BIC "Beam Box", basically a *selectable/ tuneable* Yagi in an enclosure the size of a small phonograph or turntable, has worked very well for me and a few of my friends back when we lived in apartments in areas with generally lousy FM reception and where outside or attic antennas were not allowed. Lower signal output than you'd get from a dipole (for one friend of mine, adding a signal booster between the Beam Box and the receiver made a huge improvement), but the selectable elements and bandbass filtering means that you can often greatly reduce or eliminate interference from adjacent stations. The FM-8 was the plain-Jane, 300 ohm version, the FM-10 was prettier, with smoked plexiglas top, and had a 75 ohm output as well. Last time I looked, these were fetching a hundred bucks or so on Ebay. If you cannot put up an outside or attic antenna, then the Beam Box is probably worth the money. FWIW, I live in hilly New England, and I only listen to low-power college and public radio on the left end of the dial.
Thank you for your interesting comment. Manually tuning the antenna with additional knobs can optimize reception. Prices for this product on eBay range from mid $30's to $150 as shown on 04/14/2020.
Thank you very much! I am erecting a multi-antenna mast and I now know how to address the fm band. Has anyone ever tested a multi-band discone antenna on the fm band? I am also curious to see how it receive UHF tv. That one is going on top. Merci VA3KPG
Bob, great video. Read through most of the comments and replies. Enlightening. My situation is that I have a metal roof on my house that interferes with FM reception. I saw Alan Nyhius' question and your reply below suggesting to put a vertical dipole about 1 m from the house on the side where the station's transmitter is located. I assume attic with metal roof would not be good. Should I try to put vertical dipole about 1m from house?. I only want to listen to one station and it is a repeated NPR station with antenna 5.7 miles away with power of 0.08kW (The FCC card says it is vertically polarized if I am reading it correctly). I have an old Zenith MC7030 receiver/tuner with the screws for 300 ohm antenna, no coax input. Should I use an adapter from screws to coax?, or should I use another type of wire to string out to the north side which will be about 45' away from receiver where metal roof comes down and ends? It is a gable roof and I could locate antenna at eaves or lower. Eaves are high, about 21' off ground (House on pilings). Thanks!
William, Thank you very much for your reply and question ! Since you have a radio with only a 300 Ohm input, I would attach a vertical dipole with "300 Ohm Twin-lead" from the antenna to the receiver, which will result in the minimum loss result ! The cost will be at a minimum as well..... Please reply with your result !!!!
@@robertklacza1160 Hi Bob, well I finally found a decent dipole antenna for sale. It took some doing. I really didnt want to have to mess around uncircling that one you showed on the video. Here is the link to the one I found. Ordered it today, will let you know how it performs. centerfireantenna.com/fm-band-outdoor-dipole-antenna/
Best, Jack
@@williamrink2351 It's 4 years later. Have you mounted it yet? How were your results?
Very good lecture!
Thank you very much for your reply !
Great video, good info. Just one thought. You mentioned circular polarization, and stated that it helps with minimizing multi-path interference. Well, it does - except - for that to happen you have to receive with a circular polarized antenna. Circular polarized broadcasts have the advantage that you can orientate the receiving antenna in any polarity and still receive the signal - However - either V, or H polarity of receive antenna (using only either of those), will be 3 dB down from that of what one would get if they used a circular polarized antenna for receive.
You are correct, but I do not know of many circularly polarized receiving antennas, especially on a car...
@@robertklacza1160 Good point, however I believe what I was addressing is the issue of multi-path. The advantage to true circular is that when a signal bounces off of anything, it reverses the circular direction. The original signal may be left, OR right hand circular, and when you receive with the respective direction antenna (let's say it's transmitted with "left hand", and you have a left hand antenna), the right hand signals are rejected, therefore the "multi-path" signals are rejected.
You see - any "reflected" signals come in with the opposite direction or rotation, because it flips when it hits an object, and bounces off (in this case, the reflected signals would be right hand). Your left hand receive antenna - would reject them. So, since we are NOT receiving with a circular polarized antenna (that rejects the opposite circular direction), how can we gain multi-path rejection improvement? My understanding is the main reason they transmit with both polarities, is simply because homes use horizontal mounted antennas, and cars use vertical oriented ones. Please share if you feel I missed something, OK?
.
@@stephenbay9564 Thank you very much for your added discussion on the circular polarization topic! You have covered the circular polarization topic quite thoroughly!!
This was very helpful. Thanks!
Thank you very much for your comment!
I am new to radios just today I have started my project antenna for my sw radio think in fm there are not many that I could pick but after watching this man be I should give fm as well a try. Can some tell me in India will they block fm stations broadcasts from a city to another city?
Thank you for your comment ! There is really no way, once an FM broadcast signal leaves the broadcast antenna, to "Block" it, but only can have an "Interfering" signal to mask the desired one. The way to get better reception from stations in another city is to use a "Yagi Beam" antenna, which is directional in coverage, and should be used with a rotator motor to turn the antenna to the desired city location. Please let me know if you need additional help in achieving your desired result !!
how is stereo fm broadcast?
en.wikipedia.org/wiki/FM_broadcasting#Stereo_FM
A little clarification. The folded dipoles described in my last comment each had about 288 ohms at resonance. Using the RG62 raised the impedance of each antenna to 1200 ohms. Connecting each antenna to each other lowered the total impedance to 293 ohms at a resonant frequency of 98Mhz (the exact middle of the North American FM broadcast band).
Thank you for your informative input! Some may find your connection technique rather daunting !! Thanks again, Bob
Fm antenna dipole length sir ?
The total length of the dipole is about 62"
Bob, thanks for the nice video and education. I want to make my own long range folded dipole FM antenna to cover 90 to 108 MHz stations. I understand that on horizontal it works as dipole whereas in vertical it is a "kind" of omnidirectional, correct? What should be the length of the aluminum dipole on each sides when I put in vertical position? Does the formula 468 divided by the frequency works for the vertical position as well?
The length of the dipole is the same regardless of the vertical/horizontal orientation. Wavelength of the frequency is the same both ways. The article at www.kb6nu.com/468-ham-radios-magic-number/ cites the 468 number.
awesome stuff!!
Thank you very much for your reply !
My FM radio has a single wire coming out of it. With the coaxial cable there are two wires - which of the two coaxial cables is connected to the single radio wire?
You have, unfortunately, no choice in this due to the fact there is only one wire. Make sure that the wire is about 31" long, and put it straight up in the air ! In order to use a coaxial cable, the internal circuitry of the radio would have to be redesigned.....
I think I found my new club. Radio antenna enthusiasts.
Thank you so very much for your comment !!! I really appreciate your comment !
100mhz 4 element yagi antenaa dipole length in cm.or inches how much length?
The length for the main pick up dipole is again in the neighborhood of 62" end to end. I measured my old 8 element Yagi beam FM antenna, that I believe is a Winegard brand, with the following results- the two pickup dipoles were different, the rear dipole was about 62" tip to tip, the leading dipole was about 53" tip to tip. The single reflector element being longer at 66" tip to tip, and the leading five director elements are all about 49" tip to tip. The total length of the pipe is 94", or very nearly eight feet !! I hope that helps...
Where can we buy the vertical one, the third one he showed? I cant find it anywhere.
Just buy the round one and straighten it out.....
The Stellar Labs 30-2435 can be purchased at www.newark.com/stellar-labs/30-2435/outdoor-omnidirectional-fm-antenna/dp/55W7744?mckv=sLjrascK4_dc|pcrid||plid||kword|30-2435|match|p|slid||product||pgrid|1235851176204666|ptaid|kwd-77240787909419:loc-190|&s_kwcid=AL!8472!3!!p!!o!!30-2435&msclkid=ed80094ce26411b2557b56717e4fea6e&CMP=KNC-BUSA-GEN-SKU-Electrical for $12.04 + tax+ Shipping/handling !
gracias por compartir esta información casi nadie toca este tipo de temas saludos desde Mexico
American English- Thanks for sharing this information, almost nobody touches this type of topic. Greetings from Mexico.
Beno, Thank you very much for your comment! Please share this video with others who are interested in good FM reception !!
Help me, please.
How does his dipole antenna
compare
to the cheap twin-lead ribbon antennas that was included with the purchase of a new radio ?
The simple twin-lead dipole can work well, as long as the dipole is vertcal, and the twin-lead feed line to the radio is horizontal and twisted with one twist every 8 to 10 inches to avoid picking up noise....
@@robertklacza1160 Today is February 12, 2021.
I just now discovered your reply back to me.
Thank you very much.
I have watched this video many times.
It is great & to the point.
Folded dipole. How about a 4 or 5 element yagi? You need a rotor but you get some gain and front to back ratio
This report mainly focuses on simple antennas. Rotors and multi-element antennas require much more space, complexity, and money.....
Can someone tell me what are the components of the fm antenna? A trap? I am restoring an old tube radio and it has a loop in the back of the console but I want to upgrade that to something much better. the whole 75ohm vs 300 ohm thing is a mystery to me also. when I bought my house there was an old big tv antenna not being used... can I just run a coax cable from that thing? thx!!
Dear Mr. Jam, Most of the time on old tube radios, the "Loop" antenna is used for AM pickup from 540KHz to 1600 KHz. The tan color T-shaped FM antenna made of twinlead in the background of the video is the standard 300 Ohm antenna that will connect with the "300 Ohm" inputs on FM receivers. The 75 Ohm input on FM receivers is sometimes one of the 300 Ohm inputs, with the 75 Ohm coaxial cable shield going to chassis ground. The TV antenna that you inherited could be used for FM, even though it may not be optimized for FM. It will be far higher elevation above ground, and be able to provide a greater FM signal pickup from the airwaves. To answer your question, the components of this FM antenna consists of a "dipole" conductive metal tubing bent into a flattened loop, a matching transformer, to change the "Balanced" dipole pickup into a single ended coaxial cable feed, and the feed cable itself from the transformer to the receiver. Please let me know if that answers your question. You may want to listen to the descriptions in the video to gain a better understanding of antenna terminology. Best regards....
How do I make a small loop antenna on the 433mhz attached to coax
The antenna in the video is sized for best reception at 98 MHZ. 98/433 = ~0 .226, so multiply all above dimensions by 0.226, for example, 31" times .226 = ~ 7" Go from there !! Check some Radio Amateur handbooks for more ideas !!
Very good information
Thank you very much !
The argument that there are FM stations transmitting in circular polarisation seems to be correct only for United States. In Europe, e.g. Poland there is NO circular polarisation in use. We have H and V stations ONLY, because of interference and bandwidth availability in adjacent areas. So - vertical dipole won't work in H (it would somehow, but its gain is gonna be marginal). This strategy causes some problems with multi-path in cities, but results with greater number of station allowed to transmit. So its in fact a win-win situation.
Thank you for your clarification of FM broadcasting in Europe and specifically Poland ! Multipath effects in FM reception is most prevalent in moving vehicles, but can happen in a home situation, but in this case moving the antenna to a different location may solve this issue.
Why not hang the turnstyle with one element vertical?
The horizontal element will still pick up the signals at right angles to it, producing an oval polar pattern.
tom jackson I live in northwestern Houston Texas were can I get a killer antenna for my HD-20 sangean my HDRadio in my VW gets better and more stations on HD than the home receiver in HD!
Bob, is there a way to tune out adjacent channel bleedover on certain stations with an FM antenna? I've used rabbit ears, and an outdoor antenna. I live 20 miles from a station I like to listen to, and it gets adjacent channel bleedover from 3 stations in between the one station from time to time.
That could possibly be done with a multi-element Yagi type antenna, with a rotor to point it in the right direction, providing the unwanted station is ~ 90 degrees from the desired station.
The other way to get rid of adjacent frequency stations is to get a modern FM tuner with DSP front end IC's from NXP, TI or STM. The NXP chip set is used in the Sony XDR-F1, and works quite well, but unfortunately is out of production. eBay has some available, but the prices for these reach into the stratosphere.....
I don't have that problem anymore. I now have a Sangean WR-2 radio it it gets great reception with the rabbit ears and the outdoor antenna. I don't have a yagi type antenna, but I do have a GE Jasco indoor/outdoor attic antenna that I use for tv and fm radio and it seems to work very good for an fm antenna.
thank you for this video im very happy cos im busy whit at outdoor antena now
I have a sangean radio in the garage and kenwood kt-7500 tuner inside house that I listen to. I have a basic rca rabbit ears antenna that I use for both and get good reception. A few weeks ago I was trying to listen to an fm station with Sangean in the garage that was 175-200 miles away and was barely listenable. I accidentally pushed one of the rabbit ear antennas down next to a 5' tall steel hand-truck and the signal strength went up so high it came in stereo! I tested this with my Kenwood tuner in narrow band and signal increased from 1.5 to 3.0-3.25, or basically double. So the vertical 5' antenna with enough metal mass does work great. I got a couple 8' steel pipes, stood them up about 2 feet apart and connected a thick speaker wire across to them, and then put the rabbit ears next to it. Signal went up only slightly higher, a solid 3.25. I tried with taller pipes but it didn't improve any. So it appears that a 6 - 7' tall metal antenna is about as good as it gets for FM signal.
You have discovered the "large area" antenna. The dimensions of these don't matter as long as it is big.
@@SMWTMS Hmmm, I'm going to have to play around with that. I don't care much for the stations around in the 60 mile range, but I still don't want a roof mount antenna.
After using a 6 element yagi and a rotor, nothing compares.
The cost of this antenna is about $20. A 6 element Yagi antenna and rotor can cost ten times as much... The complexity and size do give you better reception, but not many will step up to the cost and complexity
Jimmy Ray Which yagi did you use?
252 to 251 is counted as BETTER? How much do we learn from this experiment?
We learned that all of the antennas perform about the same, but there was a slight difference, that being the vertical orientation is omni-directional.
Thanks for your efforts Bob. At the end of the video you mention a segway in to part two. Was this not shared? Also, if I put an omni-directional (like the round one) or a bi-directional (like the "plus sign" shaped one) in my attic how does the length of the coax cable affect signal strength and will a powered signal booster help?
The segway was into the comparison of the Sony and Sangean AM/FM HD tuners. Please see it at my "Sangean HDT-20 vs Sony XDR-F1" TH-cam video. The coax cables have some attenuation at FM frequencies, a couple of dB per 100 feet, depending on brand and type. I recommend RG-6 by a name brand manufacturer.
The "Sangean HDT-20 vs Sony XDR-F1" TH-cam video is at th-cam.com/video/fbudkK9LzWY/w-d-xo.html
Thanks for the video. :-)
Thanks for your positive reply !
I remember as a boy AM had alot of static space on the band I would pick up many faraway stations at night CBC back then would go off the air and NeW Orleans would come in . CBS radio mystery theater if you remember that program with EG Marshall when the program would fade out you heard a mystec sound effect to the program when hearing the static.
Thank you for your comments !
I'm 35 and I never knew this niche hobby exists. I acciddntally found this video as I was looking for antenna building tutorial for my old Pioneer kp500 car stereo. That unit is a super tuner az they say but I don't know what that means lol.
The Pioneer "Supertuner" aftermarket car stereos made attempts to minimize the effects of multi-path distortion on FM reception. Some friends said the OEM car radio was better !!
What kind of outdoor fm antenna do you recommend?
I would try the round one first, easy, small, and good results.
So the 2 take aways here are that dipole antennas are good but should be mounted vertical for FM. I thought terrestrial noise bouncing off vertical structures such as power poles, trees, buildings caused a problem, or maybe is it just negligible?
I would like to know as well.
"Multi-path" reflected signals happen quite often in moving vehicle receivers, but not so much with fixed home installations. With that said, if you tune to a particular local FM station, and the signal is distorted, move the antenna around the room and 9 times out of 10, the poor reception will clear up. Of course, keep the antenna as high off the ground as possible.....
very intersting topic
Simple Antennas for easy solutions! Thanks for your comment !!
Interesting Video Bob. I have an issue in my new home and I am not a very well versed electronics guy. Have been trying to get FM reception in my shop building on an old Nikko am fm receiver. FM Reception is horrible with a great deal of static. AM reception no problem. The shop is one of those corrugated metal buildings, roof and sides. I tried inside with that "winegard" hd 6010s I think you were displaying in the video and it produced no improvement. Is the shop shielding any FM reception and do I need to go outside with an antenna? I then worry about grounding issues if I go that route. thanks for any help !!
I would suggest putting a vertical dipole outside a window mounted maybe 1 meter from outside of the structure. Choose the side that faces the most of the FM transmitter antennas that you wish to receive.
Thank You, I will give that a try.
Very informative video. But it's incorrect to say that all FM Broadcast stations transmit with circular polarization. Here in Canada, most low power stations (under 3 kW) are usually vertical-only polarization. For example, CINQ 102.3 FM.
Dimitri, thank you for your comment ! Yes, Low Power FM's typically don't have the money or space for a circular broadcast antenna, so vertical is the least costly solution for them !!
I reckon antennas are just way over my head.
As mentioned in the presentation, the higher the better !!!
@@robertklacza1160 very true, radio waves travel more freely high up
Coaxial dipole antennas (Flowerpot antenna) are cheap, easy to build and have omnidirectional performance, my airband specific variant works very well on FM broadcast 👍
Thank you very much for your comment !!
I have a Magnum Dynalab verical from the 90's in the attic, and want to run a 100 ft coax down to the basement, F type connectors both ends, what coax should I use? 50 ohm or 75?
See Page 4 of the installation guide www.magnumdynalab.com/new/wp-content/uploads/2018/05/ST-2InstallationGuide.pdf
Looking at the installation guide of the Magnum Dynalab verical antenna, it looks to be a single 1/4 wavelength mast, with no ground plane at it's base. Adding a ground plane at the base with the mast vertical above the ground plane will increase (double) the captured signal strength. The recommended ground plane would be approximately 2 meters by 2 meters with the mast in the center. If the vertical height is available, going to the folded dipole shown will have the same signal strength pickup, but without going through the trouble, size, and expense of the ground plane. I would be interested in hearing from you on your results.