Modeling the Simple Inverted Vee Antenna
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- เผยแพร่เมื่อ 17 ต.ค. 2017
- What can we learn about the Inverted Vee HF single-band antenna from the EZNEC+ model? Lots of things, having to do with height above ground, the amount of spreading, and using a metal pole as a mast. Tune in for full details! Subscribe: / davidcasler . Ask Dave Playlist: goo.gl/inaQeB. Tip Jar: ke0og.net/tip-jar
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As a QRP operator I use only Inverted "V" antennas all built to resonance. I run them all at 20 feet (6 mtr fishing pole) and spread the antenna out on guy lines to offer a ground clearance of the antenna ends from the ground of 3 feet. This antenna configuration is such an easy way to get on the air and enjoying QSO's. Many Thanks M6KVK
I am about to start doing SOTA, and this is exactly what I plan to do also.
Is it ok to put one up in the trees? Would it effect signal?
Also, are they directional in any way?
Are you using the 6M fishing pole in the centre? how well does this handle the coax etc? is it guyed in any way. thanks.
@@MikeDent I use an 8mtr pole but remove the top 2 sections in order to give the whole pole some rigidity so deals with the coax no problem. I have printed a guying ring that sits on the top of the 2nd section and guy it out with 3 lines. 73
@@theoldhobbit3640 ahh that’s interesting. my son has a 3d printer. Do you mind me asking where you got the pole. Do you have a link please? Thanks. G6PHF
Thanks, Dave. I have been doing ham radio for 60 years now, and this is the first good explanation of the Inverted Vee that I've seen (or read).
Great information Dave. I've heard you mention in several videos that you are limited to 20 feet using chain link fence top rails. Gigaparts sells carbon fiber masts that might help you get wire antennas up higher. They are much stronger and lighter than fiberglass or these chain link top rails. I bought the 25 footer and increased it's height to 30 feet by adding a five foot fiberglass garden plant support rod. The fiberglass rod fits in the end the top section and is secured by the compression clamp at the very top of the mast. Even though I'm in a wheelchair with only one usable arm, I can set the whole thing up from scratch in under five minutes without assistance.
I love this mast. It's incredibly strong and only weighs around five pounds total. It's secure enough that it doesn't require guys.. For the base, you can install a pipe (with a slightly larger inside diameter than the bottom section of the mast) into the ground or buy the tripod that's made for it. Either way, this is a great method to get wire antennas up higher. They also sell a 35 and 50 foot version of this mast. I bought the 25 footer because that fit my budget. I hope this idea is something helpful. Maybe you could review one of these masts in a future video. Thanks! Brian - W5DUI
Thank you! This is one of the few videos that talks about the end points on an inverted V. Many diagrams just cut off where the ends and assumes an amateur knows what to do. Others simply say ,” they’re tied to two trees “ but don’t explain why.
Excellent presentation with great audio!
The inverted V was one of my first antennas used on 40 meters some 50 years ago. I had elevated the ends so it became a horizontal V dipole with a center support of only 26 feet but it worked very well, especially for daytime, short skip. A dipole has a 50 ohm impedance when the angle of the V is about 90 degrees: Nice match for RG-58 or 8x cable. This early antenna had my (W2AU) 1:1 balun at the feedpoint
I plan on making another one, just for the fun of it, from wire, balun & coax I already have and this time my center support will be about 40+ feet high but the ends will be lower to the ground. It's a "forgiving" antenna and I know it will work just fine.
With the coax, it' basically a simple, single band antenna but I have used ladder line in the past on my 40 meter dipole and that meant that it performed very well on other bands as well. With "The Window Line," both my tuner and 4:1 balun were in the shack...Because the ladder line is lightweight this antenna of mine was up high and supported at the ends, each about 40 feet off the ground...I did not trim this antenna. I simply cut the wire for the bottom of 40 meters and did all the tuning in the shack which resulted in may QSO's on 80 thru 10 meters with a 40 meter antenna and running QRP as well...
I made a dipole with one side level over a flat roof, and the other side off the roof down to a fence . This antenna was for 10, 12, and 18. It worked quit well.
Thanks Dave I’m going up 25-28’ in the center and running out above ground about 8-10’ off the ground thanks a million 73’s and GOD bkess
I ran HF comms for the Air Force, we used sloping v's, I remember the legs being terminated in a box maybe 3 ft off the ground. Ran with a prop chart 8-12 mhz, OKC to San Deigo 1975. TTY and voice comms
Hello Dave, Thank you for another enlightening session. You really made the lightbulb in my head go off. I've been wanting to get on 80 meters, but the topography here just doesn't allow for a clean horizontal setup.
I decided to pick up an Alpha Delta 80 meter dipole and plan to erect it in an inverted vee. Like most of this part of the country, we have no trees, so my plan is to hang the feed-point at an approximate height of 44 feet, using a Spiderbeam fiberglass mast. and bring the legs down at a 45 degree angle, terminating 4 or 5 feet off the ground with the tie-off lines.
Thanks for the inspiration!
Thanks Dave. This is the first substantive, data-based presentation I have seen for Inverted Vee's. Very well presented and I now know how to model the Inverted Vee I will install over the next few weeks. Well done !! 73, N7MNZ
Thanks for the information as I just put up an inverted V for 40 meters. I can tune it to 1.1:1 SWR but would like to get away from the tuner if possible. You just showed me how.
The way that you mix the imperial and the metric system in your description is amazing.
Generally speaking, when frequencies science involved in your explanation you have to use metric all times.
Yes, it's mix and match. Frustrating for those who are completely metric.
@@davecasler Sure, I unterstund.
I kindly remind you that the fields of antenna development plus other radio science are completely metric.
Your work on this hobby is excellent, the HAM community need more people like you.
Please continue your excellent work, just avoid mixing metric and imperial systems into your descriptions.
Cable length, distances from the earth, antenna elements dimensions, and others must be described in metric units cause the fundamental mathematics involved in radio science are metric. (i.e. wavelength λ).
BTW, my callsign is SV5KKD, I'm fun of 20 meters (or 787.402 inches) band :P
Hopefully, one day meet you on the air. 73
@@iamasgroup About 75% of my viewers are in the United States, so I need to use Imperial units when those are in common use here. For example, in the US, coax is sold by the foot, not by the meter.
Thank you.
I enjoyed your video.
You need to run your coax from the antenna to a lightning surge suppressor mounted to a ground rod (8') to reduce static discharge and lightning induced voltages that can damage your radio finals. Then connect a piece of coax to the surge suppressor and run it into the house.
My Elmers taught me this bit of critical information.
Thanks again.
N0QFT
Very nice video. I have tried many different antennas over the year, and unless you want to invest a lot of time and money, a well built dipole / inverted V is hard to beat.
Thank you for your videos.
I had a hard time understanding the "wire" settings to manipulare for a good SWR. it took me a minute to figure it out because I didn't catch that the "wire" settings relate to a Cartesian plot instead of lengths for the wires from the feed point to the end of each wire. I KNOW it should have been obvious. And a lot of the time I fail to listen closely enough. And NO i didn't read the manual. lol
I'm commenting for the sake of other newbies to EZNEC who might not make the connection, just as I failed to. Part of that is, as a novice and upward, I calculated 234 divided by frequency to get the length for each 1/4 wavelength of the wire. I'd run the feed point wherever I could get it and tune wire lengths for an OK SWR and was happy.
Now that I figgered it out I see that EZNEC gives us a few heads ups that a pocket calculator doesn't give. The EZNEC doesn't work with wire lengths, but with the distances of each wire end from a certain place at the antenna site. It took me a minute to figure it out. I'm writing my understanding below so please let me know if I have it right.
I completely got confused because I missed that End 1 is the feed point height above ground for wire 1 and wire 2 instead of wire length for wire 1 and wire 2.
I missed that end 2 is for the horizontal distance of wire 1 and wire 2 from a point direcctly under the feed point. One of the wires must be a minus (-) number so as to have one wire to the right side and the other wire to the left side of the antenna feed point support. And I missed that End 2 Z is the height above the earth of each wire end at the low end of each wire.
I feel real silly, but I post this in case someone else who is a newbie to EZNEC has the same confusion. Thank you again for your videos.
Good information Dave.
I took a 40m inverted vee on holiday, fibreglass telescopic mast, so easy to put up. 20 foot mast against the stone wall with the centre up and ends drooping onto the wall and held by rocks, coil the ends to shorten it to tune. Worked fine.
At home it's more like a sloping top inverted U than a V.
73, Bill, G4GHB.
Sounds like you found something that works very well for you!
So, Just made an inverted V for the 10 meter band. I'm located in New York. It's slightly more than 1/2 wavelength off the ground at the center, about 20 feet up, so the elements clear the roofline. First day observations; Picked up propagation from central Canada, Nova Scotia and Maine. Made a good contact with Ontario. The radials are oriented Northeast/Southwest so very surprised by the good contacts off the side of the V. Definitely seems more omnidirectional than a dipole. The bandwidth was not as wide as I expected though, the SWR is basically flat at 28.300 mhz and up, good at the upper CB channels, but a little high on the lower CB channels. I'll probably leave it as I don't use the lower channels anyway. Very happy with it and the price was basically zero as I had the stuff already laying around the house. I would recommend it to anyone looking for a good DX antenna.
With a single 20 foot high support you can have both a good 20m NVIS antenna and a good 20m DX antenna by mounting the feed point of the inverted V at the top of the support and suspend the end of a 1/4 wavelength wire down to about four or five feet off the ground to the feed point for the vertical. Then, add four 1/4 wave radials at the feed point of the vertical that slope down to just above the ground. Of course, you will need two coax feed lines. But, you then have two antennas from which to choose using the same support and can work both NVIS and DX.
Of course, if your support is metal, you may experience some coupling to the wire vertical, which will affect where it resonates. But, you trim the antenna for resonance, anyway. And, the pattern for both antennas should still be about the same. And, the sloping radials will make it easier to get a good match to 50 ohm coax, as do the sloping elements of the inverted V.
Thanks, for the video!
73
AI4IJ
Another excellent video sir! I will now go buy materials from Home Depot, Lowes, Amazon and wherever else to start building antennas!
I have a 40-20-10 EFHW with ~66 ft of #12 insulated antenna wire and it's working pretty well. It started life as 40ft of wire and a choke with maybe 6.5 ft at the other end. It was too heavy for my first mast so I switched to wire. I met Bob from Palomar Engineering on Saturday and he sells an end fed that is 71 ftof wire and purposely non resonant. So I have now heard both sides of whether an antenna needs to be resonant or not. I may be wrong, but it seems you get more bands with non-resonant? I don't have a live Elmer so I am glad you do what you do. And even happier that you know of what you speak! As an added note. My 2 new rigs have tuners, so I have an old MFJ-271 and an LCG Z-11Pro II that I can't decide whether to keep or not. There is something to be said for having a metered tuner. The LCG works fine, but because I fined tuned the length, I don[t need either one. I did notice 20m was the worst of the 3 bands.
Well Spoken! No chest beating appreciated. You are appreciated.
Thanks for the info Dave! As a tangent.... love skiing Silverton!
Well done. I would love to see a follow up, comparing actual to the model (employing an analyzer and a watt meter?). I'm tweaking a resonant nvis 80 meter, adding a choke for the first time.
Another great Ask Dave video - thanks! I'm planning an OCF dipole in an inverted vee off the side of my house, so this is very useful information.
Good luck with your antenna project!
Great Video Dave. It should be noted that EZnec results are not always 100% accurate and in my 3 years of EZNEC modeling I have found that soil conditions and antenna proximity to ground often provide much different results in reality than on the computer. I hope you keep doing these videos in the future. 73.
I made the statement in the video that the EZ NEC results are only an approximation. I'm using a normal ground in the simulations. As it turns out my antenna test range, meaning the two twenty foot poles, are located directly over our leach field, which makes that ground pretty good. My vertical, which is about 50 feet away, is over very hard dry ground. Fortunately with lots of radials it performs well.
As I said, great video. Keep them coming :)
NIce one Rob. Interesting to see your setup. I am planning to try running a wire for my Xiegu g90, for a portable setup. I have been really happy with my antennae, which is the Diamond BB7V, which covers 0.5-28.5 mHz. Ive been very pleased with the performance, also considering i still have it attached at ground level. If i raise it, it should be even better. Worth a look. Thanks for your great content.
So much great info on this channel and good for newbys as well as seasoned hams alike.
I just asked this question in your "Ask Dave" quedtionair. You may not read this, but if you do, cancell my question on your next live.
Thank you Dave!
I am using an inverted v on 20 meters and having good results . It was the easiest antenna for me to install in my space. Like the video thanks for the effort. David Byrd KN4BHS
here in ca the green top rails go for $42.usd each. but the bare galv are only $17.usd ea.
and the brand new bundle at hd had half of them damaged.
good as of nov 17 2021.
Great video as usual Dave. Strange it’s not mentioned in the ARRL books. I think it’s probably the most common configuration for many ham’s. I have a g5rv in an inverted v pattern since I don’t have the supports or room on my property for a flat top dipole. This helped me better understand my setup, 73
The inverted V is not completely left out, but only receives a couple paragraphs. They spend most of their time in the book on gain antennas. Still, the book is very useful.
Good video as always. I moved from a acreage to a town. Now I have limited space and power lines to deal with. My fence’s are metal. Unfortunately I will have to use a vertical and get it high enough above these obstacles. 😢
I am hoping to get into HF some time soon. I have a 60 foot tower that I can put something in to hold a inverted Vee antenna out and use some pulleys to be able to take it down when a hurricane is coming. the towed has been through many storms , I just not sure about the antennas.Not sure if I will take the long wire down for a storm. Worry about that later. I want to be able to operate most HF bands without needing to go out and change something. Where can I find something easy to make that will work almost of the bands 80-6.
Hi Dave.. Like others have said great videos.. I am taking my general next week. Question.. one thing is I find on most ARRL videos no one talks about the marine setups, ICOM 802 radios with AT130/140 auto-tuners and split Backstay antennas. (single wire antenna). It is magic for most of us sailors on how it all works compared to the complicated Ham setup for land base systems. All we know it works most of the time and it is magic. Maybe you or someone else can so a few videos for sailors. There are thousands of us out here.
Hi Capt. the marvelous thing about open ocean sailing is that saltwater makes for an almost perfect radio system. All you need to do is put up an antenna along the mast and somehow get the ground side of the radio in the water with as short a wire as you can. I've seen articles in QST. Unfortunately I'm about 1000 miles from the nearest body of saltwater, so I can't do any demos. It looks like the ICOM 802 radio is strictly for use in the marine bands. That's getting into an area I really don't know anything about. Sorry I can't help you more.
Hi Dave. I was actually out today tuning my multi link dipole - 10,15,20,40 for QRP/P work. My leg ends are ALWAYS tied off with hi vis builders line (light and strong and bright) so I am much wider than 90 degrees and about 40-60cm above the ground. Feed Point is about 6m up a fiberglassmast. Tuning is as you mentioned, and SWR meter and folding back as needed from the non feed point end. Just thought I would share. Wade. VK1FWBD
Thanks for the info
Great video Dave. You answered my questions.
Thank you!!!
As are all of your videos... this one is great and very helpful. Any thoughts on a sloped dipole (e.g., a sloper) versus and inverted V. It also requires only a single support. I don't think you've previously addressed this. Thanks !
Perfect. This is the antenna I'm thinking of using. Thank you.
HI Dave, I particularly appreciated this video on inverted Vee style dipole antennas. I’ve been having trouble with 10 m communications, one of two bands I’m allowed phone communications at technician level. I realize 10 m comes and goes for long distance communications, but for local nets, I’m disappointed my conventional dipole w/1:1 balun 17 ft off the ground (1/2 wavelength) does not work. I hear faint voices under a lot of noise. I plan to experiment with an inverted Vee configuration by raising center point hopefully up to a full wavelength or close. Do you think this will improve the performance of the antenna? Also, is that software you used public domain or is there a fee involved for purchase.
Hi Dave. Thanks for your videos. I would like to see a video describing how to build a multi-band 80, 40, 30, 20, 15, 10 inverted V using ladder line to a tuner, then coax to the radio from the tuner. Thanks and 73. KFØW
Just build an 80 m inverted V, use ladder line to feed it, and you can probably tune it on any band except maybe 60.
Any tip to make it as much omnidirectional as possible and possibly to lower the angle of radiation?
want to build a 10meter antenna for rag chew with 45 miles between stations, could you tell me best wire antenna to use for this.
I have used 16 gauge auto wire, speaker wire, and even an old extension cord successfully.
good job dave, great info thanks
Very good video nice job well done from Gary in the UK 🇬🇧 👏
Great video Dave, but what hapend if the angle of the inverted V is less than 90 dedrees? Thanks.
Hi Dave, very interesting. Did you do a comparison of the patterns of an inverted V vs. a conventional dipole? I'l like to see the plots overlayed, to determine which version of this antenna would be best. -Thanks!
I build dipole should I strip the insulation off the wire? I built a 1/2 wave with pex for the insulators how balanced does this thing have to be it's hard to measure semi rigid wire when it's not taut I know I'm within a inch right now.
Hi, thanks for your nice videos. Maybe you could make some new antenna modeling videos?
Thanks, just got my General, still only have a UHF/VHF Anytone 878, but I understood all of that. KO4ZCJ
Hi, Dave. I'm about to up yet another inverted vee and enjoyed your video and analysis. The quirks of my site mean I don't match any of the extant models, and so far I've been lazy to EZNEC, but I'm pretty hopeful I can get acceptable operation. I'll be putting in a new G5RV, 24 feet up, with two sloping elements (more or less wrapped around my new house, with 90 degree axial separation) ending about 8 feet off the ground. I'll know soon enough whether it works. And also: perhaps you remember, we went to high school together! Good memories. Feel free to reach out... 73, AF6V.
How about an inverted V where the two elements are not spread out side by side, but rather sloping in another V? This is my setup. The center is attached to the house up high and the two elements slope down to opposing corners of my back yard, about 40 feet apart at the two bottom ends.
Thanks Dave! Does it matter if the inverted v or even if it was a dipole was east-west or north-south? And could I put one leg North and the other east? Or so on and so forth?
it would be great if there were a simple video that shows how to build an inverted V in EZNEC. Any chance you could make that video Dave ? Just how to enter from scratch, a simple inverted V like you have ...or maybe even a Fan inverted V for 80/40 or 40/20 ? . I fully understand all the theory, just not the program. I must be dumb I can't figure EZNEC out ...lol
Your videos have been very informative Dave, thank you! I just learned that son's school has an amateur radio club that operates repeater K2MFF, and I'm encouraging him to join and get his license. He's in his 4th semester in the C.E. program, but I think anyone in any aspect of E.E., would do well to get the practical experience gained through operating as an amateur. I was curious if you knew of any schools where academic credit is offered for obtaining a license? I think it would be a good way to bring new/young people to the hobby.
I think some high schools do. And, as it happens, all the various aspects of engineering use pretty much the same equations. It is true that there is an "engineering way of thinking" that applies across the board. So your son would find applicable challenges. And, a good civil engineer can really be of help in designing antenna and tower systems.
@@davecasler Thanks Dave; he's actually in the computer engineering program, but you're right, most engineering programs require calculus, linear algebra differential equations etc...my thought is that they're dealing with rf in these computer circuits anyway, generated by the clock and bus, and having real-world experience with coupling, interference and so on, on a macro level, might be interesting for these kids.
The only questions I have about this (so far) is that you mention making the elements longer, and folding them back. Does this electrically shorten the wire length? Do they have to be in physical contact - as in bare uninsulated wire, or is the insulation generally insignificant? If I can just fold the wire back on itself at the ends, it could make for a much more versatile antenna since I could shorten AND lengthen the elements, so I could set it up a couple of different ways.
Also if that's the case - would this only work for fine tuning, or could I fold the elements back to say ... turn a 15M antenna temporarily into a 12M or 10M antenna then just unfold it to bring it back to 15M (or turn a 40M into a 15M)? Would there be any practical implications - like having to twist the wires so it makes contact the entire length it's folded back?
Thanks Dave same great explanation at last! How high a pole for the cb band and how long should my wires be?
The higher the better for cb 27mhz
Simple and informative explanation. Will try out this configuration. Took down my non resonant 300ft horonzontal loop ant. Fed with 450ohm ladder line,barefoot w/ant tuner. Space constructions. Really came away w/great insight of inverted v
Dave got a new Icom 7300 itching to get on air . Plenty of room for a dipole . My backyard has 2 /20 ft unused lightpoles measured this morning 80feet in between.. would a hotizontal dipole be the ticket?
I am space challenged. My vee legs slope out not straight down. As soon as weather calms interested in 40 meter mast 30 feet ends up 10 feet off ground. Let you know as eznec did not seem to give me a modeling for that!
I like my v. Except it kept crashing to the ground. Mostly when away. The phantom. was so powerful that it broke a 2"pipe to fall down. After installing a fence charger. This stopped. And I have all the DX I can handle thanks. ☠️
Thank you Dave, I'm a technician ham and was wondering if you think building one of these for 2m or 70cm is Overkill just for fun. Cheers!
Yes, dipoles work perfectly well that these frequencies. If you're going to do FM, be sure to use vertical polarization.
Great video as always ! For reasons of space I am an inverted V which would mount to the peak of my roof and would need to extend at a 40 degree angle into the backyard. It would be a V with a lean to it. Can you comment on the impact that such a lean would have on a 40 meter antennae ? I am a new tech and hoping to work some relatively long distance CW on the low end of the band.
A leaning inverted V antenna will have some directionality in the direction of the lower parts of the element. If you are a tech, that means you must be interested in CW. You'll probably have good results. And upgrading to general is always an option.
I have rather limited options for getting a wire up in the air...I'm looking at instead of an "Inverted" vee, actually using a Vee. The ends of the legs would be up 40+ feet in neighbor's trees (with permission) behind me. The point (also the feed) would only be about 10 feet.. I'm new to modeling so working on it in EZNEC. I'm also wondering if perhaps instead of feeding at the point, feeding partially up one leg (like an OCFD but different). A third of the total length would be heading up into tree. The other leg would then come down to the low anchor point and continue up the other side into a different tree. I have no idea how to model this with a 4:1 partially up that leg (but working on it). Comments? I've already been told it won't work...but, I'm of Finnish descent...and as my uncle always said, "you can tell a Finn but you can't tell him much"....I just got into QRP and figure experimentation is the rule of the day with antennas.
Definitely give it a try. Look up OCFD to look at the dimensions. OCFDs are popular antennas.
Thankyou for the great videos
I have been investigating antennas
As a new ham Ve5mcr
I Would like to purchase and erect a simple for me multiband antenna. It would be located on a clear space some 120 feet wide running north south by some 200 feet long running east west with a sea container/ shop/ shack 80 feet from the west edge 40 to 90 feet from the north edge The rest of the area east of the container is a large garden and orchard
I work up this area with a rototiller. I don’t think I want ground radials. While putting up telescopic poles is an option (30 feet let’s say) after putting the garden in, I don’t really like dodging guy wires all summer. A tower could be attached to the sea can or pole put close that won’t really interfere with my work
Questions. What type of antenna is best for my purposes. How do I stabilize ? Which way should in run….I’m in Saskatchewan Canada. north of Montana…
I am getting advice from local hams. Each has their favourites. Dipoles. Vertical inverted V directionals. All the options causes brain cramps. I would like a relatively simple store bought unit to start. Then I can get into the fun stuff of designing my own
I’m getting up in age 68. Will be isolated. Climbing towers does not excite me greatly. My standard joke with the wifey as I just put up the house Christmas lights up about 15 feet is….The life insurance is not paid up….then she is inclined to stabilize the ladder when I climb. If it is paid up…who knows?
Thanks Sorry for the long msg.
Cam McLelland ve5mcr
Hi Dave thank you for all of your awesome videos. I just built my first G5RV. My 450 ohm ladder line is 30.6 feet at my top center pole on the edge of my rooftop. Each 51 foot wire is stretched to trees in my front and back yard at about a 30 degree down slope ending at 16 feet high from the ground in each tree creating my inverted V. My question is, how important is it that each end of my two wires be “inline” with each other? My two trees at each end are not in a direct line with each other towards the center pole so besides the V slope down, they are in a slight delta shape to each other. I hope my description is good enough to help you analyze my situation.
It likely doesn't make much if any difference. Wire antennas are fairly flexible in how they're placed.
Please "un-confuse" me - many other presenters stress the use of carbon fiber or fiberglass masts as opposed to metal, such as the aluminum fence top rail to which you refer. Surely a metal mast would generate RF, and if it's bottom is touching earth it would be grounded - so wouldn't a metal mast be more of a SWR liability????
MANY THANKS!
Great videos as usual. Thanks for sharing.
You're welcome.
Made more sense than everything else I've heard
Dave small house 15 feet to peak of roof I want to bracket a 20 foot length of steel antenna mast in 5 foot sections , will the feed line going up the posts give me SWR's I will not let the antenna wire hit any of the pipe.? Should I use stand off's for the feed line? New ham SLC ,UT KJ7TBR 73 John
In a world of gated communities, with fenced-in backyards, how would you apply what you've given in #102 to this trapezoidal yard shape:
It's Wider at back of house; Narrower at opposite side (at which is a med.size garden-shed [pos. Xmtr -Hut?]. 2m-high solid-steel fencing surrounds the yard, on 3 of its 4 sides (ie, all but the House side).
A laundry-drying tree (known locally as a "Hills Hoist") has been installed in the yard, off-center (w.r.t. length of trapezoid) & about at center (w.r.t. width of trapazoid). It's nearer to the house end.
One suggestion was to secure a lightweight, ~6m long, vertical Mast to the vertical pole of the 'Hoist, & use it to support the center of an Inverted-Vee & a run of RG-213 to it, and possibly a Lightening Arrestor (which could, alternatively, be mounted near ground, beside bottom end of the Hoist's vertical pole).
(Another suggestion was to secure 2x 4m PVC electrical conduits to opposing arms of the Hoist, with an eye to letting the Inverted-Vee's arms pull & bend the conduits' ends upwards, giving higher ends-above-ground distance, as well as less risk of someone walking into a protruding conduit.
But it doesn't seem to be large enough for a 40m Inv.V. So, we're going to stretch the arms out to, eg, fence posts and/or the house for support, at least 2m up from ground, albeit with some sagging possible.)
THE QUESTION: What effects might the 2 longer runs of Fencing (which are Parallel to the run of the Antenna, & less than 1/2 wavelength from it, on each side of the yard) cause to, eg, directionality & overall performance of this Inv.V antenna?
Can EZNEC+ model the effects of all the metal in those parallel fences?
Would some other type(s) of ~nearly horizontal wire-antenna be the better choice? If so, why?
Thanks, Dave (or anyone else with something to add, here. :~)
The only way to know if a given antenna will work is to try it. Any antenna is better than no antenna. Perhaps some other viewers have additional suggestions.
Very good explanation, as always. However i am missing the exact lengt of the 20 dipole. Also the correct angle and hight off the ground from the end of the dipole. I have a 14 meter high metal tower and would like to make an inverted V antenna . I could make 1 for 20 meter as its to low for 40 meter considering that the dipole must ideally be 1/2 waverlenght high. The idea is to do long range DX. Thank you 73's ON3FOX
You can get the metric antenna length equations from the Internet. In Imperial measurements, a half-wave dipole made of wire is length (in feet) = 468 / f in Megahertz.
Can I hide the antenna by stapling it across the peak of my house. 6/12 pitch, in the inverted V shape?
Came here for the antennas, but digging the Hard Rock shirt! Do you do comms there?
Great Video Dave, Thank You.
Is an antenna matching box really necessary if you have a matched antenna and if you don't do you get any more power out to the antenna are is all the extra power dissipated in the matching box.
Hello,how are you doing today, can I mount my mobile antenna in the roft top on my tahoe leaning slanded backward, my SWR are 1.1 ans 1.2 50 ohms 11 meter 1-40 channels, thank you so
What about non- inverted "V" at 4m up?
Thanks Dave! New Tech and learning as much as I can! 73 KO4KHB
I have a alfa delta EE if my center points is 37ft how low my end points have to be
Thanks Dave, a great vid for us new hams. 73 DE MW7GIB
I am in Idaho and want to orient my inverted v in a N/S axis so radiation is primarily E/W. To do this, my mast and the south half of the wire would be on level ground, but the north half of my antenna would need to follow a slope downhill. This means that half would end up at a steeper angle and would be nearer the ground for a good part of the run. Any ideas how this might affect radiation?
Thanks for the videos!
The first 7 minutes you have the center of the inverted V at 33 ft(half wave) but after that it appears you switch to some other height. The pattern shown at the 9:34 minute shows the max radiation is at 90 degrees and I am wondering what that height was corresponding to that plot. Also mentioning NVIS when talking about a 20 meter antenna could be confusing to a new ham as NVIS is not going to happen on 20 meters. It will only happen when operating near or below the critical frequency. I think it would be a rare day, and unusually high solar activity to experience it on 20 meters.
Sorry, this video is pretty old so I don't remember the modeling specifics. But you are correct, that 20m is not NVIS territory. Perhaps we'll have such a spectacular solar cycle that it will be!
@@davecasler It would be nice if we had a really high solar peak!
i run a horizontal dipole in my attic it does better then the inverted v
Great videos. I would like to use a SG 237 antenna tuner on a V antenna while camping in my RV. Hopefully, that combination will give me access to additional bands. The problem comes in that the SG 237 tuner needs to be right at the feed point. The tuner is big and bulky. I want to have the "V" antenna feed at the bottom of the "V" near the ground (where I can set the tuner on the ground) and the antenna arms stretched at 90 degrees to each other and aimed at the heavens. Will this work?
It may very well. But note that the tuner is designed to feed a length of wire, so try that too.
I do have a 78' 4 way guyed pole tower how would the guy wires effect the antenna?
If your guys are metal they will certainly affect the antenna. That's why a lot of people these days are using Phillystran guys (or however you spell it) because they're not metal and yet are extremely strong. Otherwise the guy wires need to be broken up with insulators every so often. The ARRL antenna book talks about this.
I checked Lowes and Home Depot, to find that their poles are not aluminum but galvanized steel.
Hi Dave, my alpha dx-ee parallel dipole (10-40m) is on a metal push up pole about 25 ft with a wooden broom stick between the push up mast and the center insulator. The ends of the antenna are up about 10 ft off the ground. Do you think the metal push up pole is negatively affecting performance? Thank you for your awesome videos. W7mss
Nice video, I ran HF when in the military, we had "sloaping V" set up at tinker OKC, talking to SanDiego navy guys, I remember the legs of the V being attached to a termination box, maybe 3 feet high. We were running 12-18 megs using a prop chart, I was the guy calling QSY's 3golf, 2 papa ect,ect. Ran a hugh Tropo setup from "the hill" 3rd mobile combat comm group, we were all mobile world wide deployable. I was under the asumption that the V had it over the dipole, thanks for the info. If you guys want to see some big stuff go google earth to Cyprus and check out Akrotiri Radio Relay at the salt lake. No words to descibe the size of the Rohmbik and others there, or the old "elephant cage" inncredable old tech, I am proud to have been part of it.
great video as always. I am experimenting with a V antenna. but instead of being inverted, setting it at a 45deg angle to the ground and having the ends of the dipole 10 foot off the ground. if I ever get it perfected I'll let us know. 73s. KC8FZK...
Great video Dave, but I have a question on my OCF dipole. I have a Buckmaster OCF Dipole 7 band antenna. The balun is 15' above my chimney, the roof is 18' above the ground. I'm figuring that gives me 33' at the apex. The 45' long element is strung to my tree in the front yard, about 25' above ground.(pointing South) The long 90' element is the questionable one. I live in Colorado as well, the Front Range. I'm on top of a hill close to Golden, CO. my backyard is where the 90' element is heading North. About 45' of it is running through a 1 1/2" PVC coupling which is tie-wrapped to a chain-link fence post 10' above ground level (to prevent resonating with the metal pole). The rest of this wire is headed downhill and lands on a fiberglass pole about 8' off the ground.
Question: Am I losing out by having that part of the antenna sloping downhill? Would it be better to raise it above my home's ground level? The easiest solution would be to run that last part perpendicular to the fence post, but I'm afraid that would mess up my East-West contacts.
The antenna will tend to radiate in the direction of the downward part of the antenna, but dipole directionality is not that large. You're probably okay.
Thanks Dave. How well do you think a 20 meter half wave dipole will work if I place it along my wood fence line that is about 7 feet tall. I don’t have much else to raise it to. Also I will be feeding with with coax center fed 259. Do I need anything else for it to work well??? Thank you.
Yes, height. 7 feet is too low. Try a method I use. Get four pieces of aluminum fence top rail from Lowes or Home Depot. These slide into each other. You can use two to make a 20 foot pole, so with 4 you'll have two 20-foot poles. Prop these up with UV-resistant guy rope and hang the dipole between them.
Nice shirt!
yeh every body has there opinion but i want experience thats why im here and i got so many questions!
first Q....can you do NVIZ on 11.11m?
I just passed 2 tests, should get my General someday soon. I will ge starting with VHF but want to get into HF sometime soon. The price for VHF is low, the price for HF radios is much higher. I have a 60' tower at my house and a nice size yard so I hope to have a dipole antana for 3 or 4 bands when I can save the money for a radio. Thank you for all the information you give. I think I will hold the ends up with the top rail pipe you talked about. I am not sure how much pull to the side they can take, with the long wire dipole antanna pulling on it. But I can work that out. With 60' foot center and 10-20' ends what kind of pattern should I get with a multi band dipole?
It would be very much like an inverted V. In other words it won't be that much different from an ordinary dipole.
Great video. But what I miss is: what happens if you not only pull the as an inverted V down wards, but also slant them down side ways like l\
Would this result the inverted V getting a direction where it sends of to more and listens better?
Thanks in advance.
I would think so.
David Casler reason for experimentation. Thanks.
Dave: So if one were to use a balun, do you think this would be a multiband antenna? Also, if one did have a 60' tower like I do, and the ends of the wires were considerably higher from the ground (say 20' or so) would one expect a better departure angle?
Pretty much any length dipole that is a half-wave or greater at the frequency used, plus fed with open wire or ladderline, and a really wide range tuner, can be used on pretty much any frequency. Antennas actually don't have to be resonant, as long as the entire system (counting tuner and feedline) is.
Thanks, Dave. That answered some of my questions. N0QT
N0QFT
How accurate is modeling software like EZNEC? What confidence can we have that the results obtained actually are correct?
The modeling software built on NEC2 is good as long as there are no unusual conditions. NEC2 makes a lot of assumptions.
Thanks Dave for your great videos! Much appreciated! Best 73 de SA7LOO
You're welcome!
In a dipole ,, is only one side of the antenna the transmitting side (hot side) or is both ?
both sides
Thanks for the video.
You're welcome!