As a retired engineer and new ham playing with antenna designs and modelling. I had the same question OCF vs EFLW ("random"). Aren't they essentially siblings or kissing cousins at least? You answered it! Non-resonant antenna length and relatively shorter counterpoise for the EFLW and consequently higher impedance. You confirmed my sanity. Thanks. Just recently found you channel. Excellent.
I recently learned that the 71" end fed random wire I use and the 66" OCFD I keep on hand as a backup antenna both need to be used with a remote antenna. I always use my desktop LDG auto tuner, but I am sad to hear I now have to buy a better remote tuner and mount it at the base of my mast. Then when I saw the price tag on the Icom Ah 730 (which would work nicely with my IC-7300) I had sticker shock! Wow that thing is big and expensive! Man, it's always something with this new hobby.
I once had acres and acres of land and at the suggestion of a friend I built a 160 meter full wave loop. It was a worthwhile project, the loop really delivered the DX. I'm back in the city now and employ a Rybakov (4:1 UNUN), a 135' EF (9:1 UNUN), and an OCFD (4:1 Balun). All three work well, and have their own plusses and minuses.
I'm the one who asked the first question. So, would you recommend the loop? An 80m skyloop may be an option. I don't have much interest in 160m. How did you get the loop antenna in the air? How high? I am trying to pick between long end fed random, OCF dipole and a loop. End feed seems easiest due to putting the connection by the house.
@@bassmanjr100 Thanks for asking. I lived on a hillside with some deep ravines and I supported two corners of the delta loop with 2 10' chain link fence rails stacked on each other. Elevation below the loop was admittedly variable. Not really ideal. The feed point was at my ham shack above the detached garage. If I had to choose between my 135' EF and the OCFD, I'd choose the EF, in spite of it requiring a tuner.
@@TheSmokinApe I've been shocked how well the Rybakov gets out to Europe from Idaho. I've done a few side by side comparisons and it smokes the EF and the OCFD with DX multihops. And such a small footprint. Low angle radiation really is a thing, hi, hi. 73, and thanks so much for what you do.
Hey Bdub, I have to say I agree. I have been blown away with the CaHRtenna Poseidon, very similar to a Rybakov, and it's ability to get DX. I'm sure part of it is the favorable conditions with Cycle 25 but the easy of setup, small footprint and simple design can't be beat. Thanks for watching the videos, glad to hear you like them 👍
A very good explanation of the OCF dipole. Due to my lot size I have been using a 66' Wndom in an inverted vee for several years. It has served me well on 80-10m. Thanks for doing this type of videos. KC8WVG 73
I like the new format. Just don't stop the old format. You have been a wealth of information on the technical end that we can count on for good information. I may deviate a bit from time to time, but your info is solid. Much appreciation and respect.
Thanks gfodale. I don't plan to change any of the old stuff, I get asked the same questions ofent which is understandable, so I wanted a way to share be able to share answers with a wider audience. Glad you like the video and thank you for watching 👍
Thank you, sir! I appreciate it. Cheers. That inverted L configuration you mention gives me some more ideas to play around with too. That's always a good thing... (just don't ask my wife about it). 🍻
I used a 40 meter commercial off center fed dipole for one reason: there were two trees in my front yard 70’ apart and a right angle feed to my upstairs shack was right at the 1/3-2/3 portion of the antenna. So it fit between the trees and the coax feed came straight into my shack. I used a tuner on 30 meters but the other bands were matched quite well. It was not objectionable to my wife and worked well until we moved a few years later.
I’m currently running a 80m ocfd with a balun designs 4:1 balun and a atu-100 tuner. The antenna works well even though feed point is only 22’ high with ends tapered down slightly. I would love to be able to dial it in better but I don’t know how to adjust it.
Good video of a complex subject! I prefer single band antennas and have several. Actually I prefer single band dipoles broadside on the direction I want to work. A good Yagi may be a S-unit better but is much more costly and takes a lot more effort. I have had them and they work but the dipoles do almost as good. Regardless of the antenna, no one antenna does it all! I like fan dipoles as they give single band performance off one coax. My 20/10 meter dipoles are not much more effort to build than a single dipole. Trying to do a 40/20/10 fan dipole takes more patience but the results give me excellent results. I use spacers between the dipoles so all the dipoles are broadside to the same direction. Since I cut my antenna for the CW band, my 40 dipole covers 15, but the pattern is not broadside as with the halfwave dipoles. I frequently hang a temporary 15 meter dipole broadside on Europe for DX contests. All halfwave horizontal antennas will have essentially the same pattern. They are resonant and can be fed anywhere. Center fed presents less problems but OFC can give easy multiband coverage. The transformer ratio and location varies and are a compromise to accommodate the various bands. If coax is good and inherent loss is small, the built in tuner in most radios can fix a lot of mistakes. Height above ground determines the peak radiation angle for a horizontal antenna. Usually the lobe is rather broad between the 3 dB points, for moderate heights. Higher antennas have multiple lobes which results in deeper nulls and sharper lobes. Great for extreme DX, not so much for everyday use.
@James-ci3lx yes you are about right. The two element Yagi gives the most gain at about 4 or 5 dB over a dipole. To get even 3 dB more gain you have to double the number of elements and the boom. Adding one element does not do much after the first parasitic element. I think the log parasitic arrays are not for the serious contesters. They are just broad banded with not enough gain compared to mono banders. I think of guys like W3LPL who have really super stations. I have visited him and he has given many presentations on Contest and DX antennas. Myself I am happy to work 1000 QSOs in a DX contest and 100 plus countries on two or three bands with my dipoles. I have had 6 element 10 meter Yagis and 4 element 20 meter Yagis at 70 feet and that was a lot of work plus a lot of expense. I have just about as good luck with the dipoles now. Last time I did a 10 meter contest with Yagis I could not rotate them fast enough and decided three dipoles on a switch would do it faster even if I gave up a couple S units!
nice job. a lot of end fed with a counter poise can be a off set center fed. just depends how you look at it. most do not count the counter poise. but it is part of the antenna system. solar weather crazy. getting buffering on internet a lot lately during the day. even noticed the GPS lock in car nav system was off the outher day. ham bands been messed up. farmers having trouble planting crops with GPS needing a good lock for precise seed planting. getting high noise 80/160 meters making un usable in NY for me. this is common . their is a random wire center fed. that uses a 9:1 Balun . still needs tuner. same wire lengths just 2 of them. still prone to common mode current. have not tried that yet. Walt made one with speaker wire and worked great . the trouble I had with off set center fed di pole was tunning. and keeping feed line at right angle to antenna. 73's
@@TheSmokinApe waiting for 11 meters open back up. big JEEM on 11 meters ! I herm his area to NY before. heat up that green toroid in 11 meters SSB 12 watts .
Good stuff Apeman. I like this new series. I was just looking at a VK seller for an OCFD and may buy it for my QTH. I asked him for a pic of the toe-roid and he sent me a pic.... I need to show it to you. Dual core, both with different windings. May send you the pic on Discord but just don't share it just yet as I'd need to ask for his permission. I think you'll be interested to see it. It's new to me anyway. :)
Been looking at a better antenna to cover more frequencies.. I am currently using a 20m inverted V,, just looking to utilize more frequencies,, you know how us ham guys are ,, just throw money at it!! LOL! great segment!
This is a good series. Not sure if this is something you’re doing regularly, but if you need another topic, capacitive hats on antennas might be an interesting topic
Hey Jeff, I plan on doing a few of these each month. Glad to hear you like the format. I do have some plans for capacitance hats but it’s pretty far down the list. Thanks for watching 👍
A dipole antenna has a centre feed point impedance less than 50 Ohms and the legs of the dipole are fixed. How do you increase the impedance at the feed point to match the 50 Ohm transmission line? Why is the impedance of the HAM radio typically 50 Ohms.?
A dipole mounted 1/2 wave above ground has a feedpoint impedance of about 73 ohns. You can adjust this by changing the length of the legs or raising or lowering the antenna. 50 ohms is a good compromise impedance for low loss and maximum power.
@@TheSmokinApe If the antenna was fed slightly off centre would the feed point impedance increase? Is 50 Ohms the output impedance a radio's RF amplifier?
I'd appreciate advice regarding HT rechargeable batteries. I have TYT TH-350 (LB-75L) batteries that will not fully recharge and deplete very quickly. Any suggestions? Thanks and 73! Tim VE3TCS
Yes. But the particular radio will depend on the band your police use, whether they use trunking or not and if they use encryption. Your best bet is to check out Zip Scanners, they have a database that will tell what is needed for your area 👍
So you said you don't really like fan dipole are you saying you don't really like the dx commander because it is basically a fan dipole put up vertical direction
Hey VTP. So, its not that I don't like fan dipoles, I'm just not a fan of them... tuning them can be difficult and the elements do cause interactions with each other. When I look at a DXC, I see a fan vertical monopole and not a dipole. It's a muilt-element vertical with a ground plane for capacitive coupling to Earth. Given the vertical is good for low angle take off, which is good for DX contacts, I think the compromise of multi-element interaction is more than acceptable. Also, with the DXC you do not have the height above ground issue I covered in the video.
As a retired engineer and new ham playing with antenna designs and modelling. I had the same question OCF vs EFLW ("random"). Aren't they essentially siblings or kissing cousins at least? You answered it! Non-resonant antenna length and relatively shorter counterpoise for the EFLW and consequently higher impedance. You confirmed my sanity. Thanks. Just recently found you channel. Excellent.
Glad it was helpful Phil, thanks for watching 👍
I recently learned that the 71" end fed random wire I use and the 66" OCFD I keep on hand as a backup antenna both need to be used with a remote antenna. I always use my desktop LDG auto tuner, but I am sad to hear I now have to buy a better remote tuner and mount it at the base of my mast. Then when I saw the price tag on the Icom Ah 730 (which would work nicely with my IC-7300) I had sticker shock! Wow that thing is big and expensive! Man, it's always something with this new hobby.
Don’t worry about all that stuff, if your current gear is working for you then keep using it 👍
Dropping The Knowledge!
Thanks TO 👍
Cool series you got going Ape!
Thanks BA 👍
I once had acres and acres of land and at the suggestion of a friend I built a 160 meter full wave loop. It was a worthwhile project, the loop really delivered the DX. I'm back in the city now and employ a Rybakov (4:1 UNUN), a 135' EF (9:1 UNUN), and an OCFD (4:1 Balun). All three work well, and have their own plusses and minuses.
I'm the one who asked the first question. So, would you recommend the loop? An 80m skyloop may be an option. I don't have much interest in 160m. How did you get the loop antenna in the air? How high? I am trying to pick between long end fed random, OCF dipole and a loop. End feed seems easiest due to putting the connection by the house.
I’ve been using a Rybakov style antenna for a few months now and love it 👍
@@bassmanjr100 Thanks for asking. I lived on a hillside with some deep ravines and I supported two corners of the delta loop with 2 10' chain link fence rails stacked on each other. Elevation below the loop was admittedly variable. Not really ideal. The feed point was at my ham shack above the detached garage. If I had to choose between my 135' EF and the OCFD, I'd choose the EF, in spite of it requiring a tuner.
@@TheSmokinApe I've been shocked how well the Rybakov gets out to Europe from Idaho. I've done a few side by side comparisons and it smokes the EF and the OCFD with DX multihops. And such a small footprint. Low angle radiation really is a thing, hi, hi. 73, and thanks so much for what you do.
Hey Bdub, I have to say I agree. I have been blown away with the CaHRtenna Poseidon, very similar to a Rybakov, and it's ability to get DX. I'm sure part of it is the favorable conditions with Cycle 25 but the easy of setup, small footprint and simple design can't be beat. Thanks for watching the videos, glad to hear you like them 👍
Very well done son. Keep the lessons rolling. 73
Thanks Hollywood 👍
A very good explanation of the OCF dipole. Due to my lot size I have been using a 66' Wndom in an inverted vee for several years. It has served me well on 80-10m. Thanks for doing this type of videos. KC8WVG 73
Thanks KC8WVG 👍
Great info Ape, most just roll over the fine points
Thanks Chuck 🍻👍
I like pictures so I will give you a 👍. Excellent job Ape!
Thanks Mr Mudz 🍻
I like the new format. Just don't stop the old format. You have been a wealth of information on the technical end that we can count on for good information. I may deviate a bit from time to time, but your info is solid. Much appreciation and respect.
Thanks gfodale. I don't plan to change any of the old stuff, I get asked the same questions ofent which is understandable, so I wanted a way to share be able to share answers with a wider audience. Glad you like the video and thank you for watching 👍
Excellent format! Love what you’re doing!
Thanks BJHS 👍
Thank you, sir! I appreciate it. Cheers.
That inverted L configuration you mention gives me some more ideas to play around with too. That's always a good thing... (just don't ask my wife about it). 🍻
Haha, good luck with the antenna 👍
It’s nice to see the OCFD getting some love. I like using them but also need to learn more about them.
I do like them and hope to get a build done at some point, just a bunch of stuff on the list. Hopefully soon...
I used a 40 meter commercial off center fed dipole for one reason: there were two trees in my front yard 70’ apart and a right angle feed to my upstairs shack was right at the 1/3-2/3 portion of the antenna. So it fit between the trees and the coax feed came straight into my shack. I used a tuner on 30 meters but the other bands were matched quite well. It was not objectionable to my wife and worked well until we moved a few years later.
That's awesome David 👍
I’m currently running a 80m ocfd with a balun designs 4:1 balun and a atu-100 tuner. The antenna works well even though feed point is only 22’ high with ends tapered down slightly. I would love to be able to dial it in better but I don’t know how to adjust it.
You would need to measure both sides to determine the ratio from Element to Ground leg and then when adjusting add or remove the same ratio of wire 👍
Good video of a complex subject! I prefer single band antennas and have several. Actually I prefer single band dipoles broadside on the direction I want to work. A good Yagi may be a S-unit better but is much more costly and takes a lot more effort. I have had them and they work but the dipoles do almost as good. Regardless of the antenna, no one antenna does it all! I like fan dipoles as they give single band performance off one coax. My 20/10 meter dipoles are not much more effort to build than a single dipole. Trying to do a 40/20/10 fan dipole takes more patience but the results give me excellent results. I use spacers between the dipoles so all the dipoles are broadside to the same direction. Since I cut my antenna for the CW band, my 40 dipole covers 15, but the pattern is not broadside as with the halfwave dipoles. I frequently hang a temporary 15 meter dipole broadside on Europe for DX contests.
All halfwave horizontal antennas will have essentially the same pattern. They are resonant and can be fed anywhere. Center fed presents less problems but OFC can give easy multiband coverage. The transformer ratio and location varies and are a compromise to accommodate the various bands. If coax is good and inherent loss is small, the built in tuner in most radios can fix a lot of mistakes. Height above ground determines the peak radiation angle for a horizontal antenna. Usually the lobe is rather broad between the 3 dB points, for moderate heights. Higher antennas have multiple lobes which results in deeper nulls and sharper lobes. Great for extreme DX, not so much for everyday use.
Hey DP, thanks for the insightful comment. I do agree a dipole is hard to beat.
@James-ci3lx yes you are about right. The two element Yagi gives the most gain at about 4 or 5 dB over a dipole. To get even 3 dB more gain you have to double the number of elements and the boom. Adding one element does not do much after the first parasitic element. I think the log parasitic arrays are not for the serious contesters. They are just broad banded with not enough gain compared to mono banders. I think of guys like W3LPL who have really super stations. I have visited him and he has given many presentations on Contest and DX antennas. Myself I am happy to work 1000 QSOs in a DX contest and 100 plus countries on two or three bands with my dipoles. I have had 6 element 10 meter Yagis and 4 element 20 meter Yagis at 70 feet and that was a lot of work plus a lot of expense. I have just about as good luck with the dipoles now. Last time I did a 10 meter contest with Yagis I could not rotate them fast enough and decided three dipoles on a switch would do it faster even if I gave up a couple S units!
nice job. a lot of end fed with a counter poise can be a off set center fed. just depends how you look at it. most do not count the counter poise. but it is part of the antenna system. solar weather crazy. getting buffering on internet a lot lately during the day. even noticed the GPS lock in car nav system was off the outher day. ham bands been messed up. farmers having trouble planting crops with GPS needing a good lock for precise seed planting. getting high noise 80/160 meters making un usable in NY for me. this is common . their is a random wire center fed. that uses a 9:1 Balun . still needs tuner. same wire lengths just 2 of them. still prone to common mode current. have not tried that yet. Walt made one with speaker wire and worked great . the trouble I had with off set center fed di pole was tunning. and keeping feed line at right angle to antenna. 73's
Yeah, those flares really messed things up 👍
@@TheSmokinApe waiting for 11 meters open back up. big JEEM on 11 meters ! I herm his area to NY before. heat up that green toroid in 11 meters SSB 12 watts .
@@robertmeyer4744 haha, he is all in on the 11
Good stuff Apeman. I like this new series. I was just looking at a VK seller for an OCFD and may buy it for my QTH. I asked him for a pic of the toe-roid and he sent me a pic.... I need to show it to you. Dual core, both with different windings. May send you the pic on Discord but just don't share it just yet as I'd need to ask for his permission. I think you'll be interested to see it. It's new to me anyway. :)
Thanks for sending the pics over Don 👍
Been looking at a better antenna to cover more frequencies.. I am currently using a 20m inverted V,, just looking to utilize more frequencies,, you know how us ham guys are ,, just throw money at it!! LOL! great segment!
Thanks for watching McGrath, glad you liked it 👍
This is a good series. Not sure if this is something you’re doing regularly, but if you need another topic, capacitive hats on antennas might be an interesting topic
Hey Jeff, I plan on doing a few of these each month. Glad to hear you like the format. I do have some plans for capacitance hats but it’s pretty far down the list. Thanks for watching 👍
Dear Ape,
As always time very well spend watching/listening to your videos. Thank You. FM KQ4IXD
Thanks FM, glad you like the videos.
A dipole antenna has a centre feed point impedance less than 50 Ohms and the legs of the dipole are fixed. How do you increase the impedance at the feed point to match the 50 Ohm transmission line? Why is the impedance of the HAM radio typically 50 Ohms.?
A dipole mounted 1/2 wave above ground has a feedpoint impedance of about 73 ohns. You can adjust this by changing the length of the legs or raising or lowering the antenna. 50 ohms is a good compromise impedance for low loss and maximum power.
@@TheSmokinApe If the antenna was fed slightly off centre would the feed point impedance increase? Is 50 Ohms the output impedance a radio's RF amplifier?
Yes and the impedance of most radios is 50 ohm
Indeed, a random wire with counterpoise is essentially a random OCF dipole.
Yeah, they are pretty much the same 👍
I'd appreciate advice regarding HT rechargeable batteries. I have TYT TH-350 (LB-75L) batteries that will not fully recharge and deplete very quickly. Any suggestions?
Thanks and 73! Tim VE3TCS
It’s probably time for new batteries, sorry to be the bearer of bad news
tnx! I was afraid of that. Very quick reply noted and appreciated.
good luck with it 👍
Is there a radio good for listening to police calls?
Yes. But the particular radio will depend on the band your police use, whether they use trunking or not and if they use encryption. Your best bet is to check out Zip Scanners, they have a database that will tell what is needed for your area 👍
Thank you
So you said you don't really like fan dipole are you saying you don't really like the dx commander because it is basically a fan dipole put up vertical direction
Hey VTP. So, its not that I don't like fan dipoles, I'm just not a fan of them... tuning them can be difficult and the elements do cause interactions with each other. When I look at a DXC, I see a fan vertical monopole and not a dipole. It's a muilt-element vertical with a ground plane for capacitive coupling to Earth. Given the vertical is good for low angle take off, which is good for DX contacts, I think the compromise of multi-element interaction is more than acceptable. Also, with the DXC you do not have the height above ground issue I covered in the video.