The whole hobby is about experimentation and self learning,may it always remain so Kevin!!

@terrygunderson5681

5 жыл бұрын

Absolutley, 73

I’d much rather see a failed experiment on your channel and learn something new then go to qrz and get lambasted by an arrogant ham for asking a “stupid question” This is why I love your channel. You speak to everyone at the same level and don’t protrude any superiority onto others.

@davidbyrd5065

5 жыл бұрын

Good or bad results are still results. Something was learned. David Byrd KN4BHS

Sometimes you have to do things that don't work! Then you have first hand knowledge!

The folded dipole was my first antenna back in the 1954 on 80/75 meters. The feed line was window line feed into an antenna turner at the rig and it worked great for me. Also I made my first 6 meters contact using it. Of course I think that the windom I'm using now outperform it plus through an turner you can using it on all HF bands.

Kevin, appreciate the video's. I live in a high noise environment, so the folded dipoles are of great interest to me because they are quiet compared to a vertical. There are lots of hams in the same boat.

Hi Kevin, KG5PP here. Your fixed folded dipole test is interesting. I suspect something is wrong in the balón or in the wire elements. Murphy is always around to screw things up during experiments. FWIW I ran a rooftop fixed folded dipoles on 17 meters and 20 meters for several years, long ago and faraway in South America. It was a very fine antenna type and performed as well as or better than many yagis in the area. I did not use ladder line. I used 12ga solid copper and home brew polymer separators. Testing and fine-tuning of impedence, SWR, resonance, etc.,was done using MFJ gear. The balun was a commercial-grade 4:1 device. Transceiver was Yaesu FT-890. Signals came in strong and clear with less noise than on my standard dipoles. Contacts began in morning with Eastern Europe, Mediterranean, North Africa, Canary Islands, Florida, East ?Coast, Midwest, and continued westward to West Coast, then Hawaii, and Japan - at nightfall in my location. Contacts in South America were also very good on both bands. I weatherproofed all connections and reinforced joints to avoid wind issues and random bird issues. If you repeat the experiment someday, I would be interested to learn the results. The folded dipole should give clearly better performance IMHO and experience. 73’s

A wise ham once told me, there are only 3 antennas you ever need to make to TX/RX. A dipole, a folded dipole, or a yagi with the driven element made of one or the other. I find that the upper frequencies work better folded, and the lower work better with the standard dipole. I strictly run folded dipoles for UHF/VHF, or a folded dipole yagi. I run dipoles, or arrays of them for lower bands. A 4:1 balun hooked to a folded dipole, is by far the best antenna for VHF/UHF. I’ve never had better results with anything else. End fed folded dipoles, aka slim jim’s are also incredibly convenient for a large chunk of frequencies 6m and up. Anyways... great video.. I found the same issue on the lower bands, and I assumed the folded dipole was bringing in too much wide band signal, and the overall effect is a deafening of the receiver. A folded dipole on the lower bands requires filters, and a very good match. (Balun)

How bout an 'air core' balun... they can be made to work better than balun wrapped on cores - on 1 or 2 bands... but folded dipoles are fixed band critters any way... great video... with 2 dipoles up maybe time to try phasing them too.... oh, the folks at qrz... trying to 'eat your lunch'.... heres a reply may consider using... "... umm... still waiting to see your 'positive' contribution to the hobby ....video..."... best 73 Scott

Thanks for the video. The takeaway is not the difference in performance but the broad-er band nature of a Folded Dipole. I'm putting a folded vertical dipole on an aircraft mounted onto the fiberglass cabin because I want a broader band to cover the Aircraft Band better than a simple 1/4 wave antenna.

we have repeaters here on UHF, mine is regular diamond omni, my friends repeater is stacked folder dipole, i can see the quieting on my friends repeater, your experiment is real, it has a band pass characteristics. cleaner reception

This video was in my KZread recommended page... A dipole, and conventional folded-dipole have many of the same characteristics, and work pretty well. But there is another antenna, rarely talked about, in the HAM community. The Terminated folded-dipole. This antenna was tested by both the US Navy, and the Japanese Army, prior to WW2. And both discovered a basic Truth. It is the best wire antenna over all, in the World. Why settle for some kind of resonance on one (sometimes 2) bands, when a terminated folded-dipole can work across 8-bands; normally 80-10 meters? Without an antenna tuner. And can be had to handle legal-limit power levels, if needed. And, if you slope it more than 22-degrees, it becomes omnidirectional. Is partially insensitive to roofing, and minor metallic surroundings. And it suppresses roughly 6-Sunits of ground-circuit based noise (that’s S-units, not decibels). Even the terminating resistor absorbs less than 10% of the antenna’s power rating. This antenna is far removed from dummy-load status. In short, it is perfect for HAM’s, especially those that like to experiment with basic propagation problems, in a fashion that removes the antenna from most of the calculations. Many HAMS have been told the Terminated-Folded-Dipole is a dummy load... but it’s not. It works as well as many, produces uniform hi-quality performance, and is just as durable as any other wire antennas. Its circuit resembles a Rhomboid antenna, without large areas of space required. Yaesu and Icom both market one antenna each. Both are Terminated-Folded-Dipoles. And there is a good reason. Yaesu’s antenna is 83-feet long. Icom’s is 90-feet. And both are basically (not perfectly) flat across 80-10 meters. I’ve used them for years, and work quite well coast-to-coast, in the US. Give it some thought...

Thsnk you for showing your experiments!!! This is real world teaching that I can actually walk away with known experience!!!

Different orientation and location will cause different results. If you move each antenna to the other's location, you will likely see the results reverse. If you do not, then there are other variables making them different. A 1/2 wave dipole works like a dipole. The only difference is folding broadens the bandwidth a bit, as you observed, as the effective diameter increases. Try a dipole made with the same window line but with the two conductors shorted at the ends and at the feedpoint. Bandwidth is increases that way, too. 73 K5RX

I'm not a ham operator but a cber and I have a square diploe antennas about 31 feet high and it works fantastic and I enjoy it!! I love The ham technology because I applied to cb/ 11meters!! It's a Charm!! Thanks for sharing your experience!!✍ LIKEMAN 530!!

@terrygunderson5681

5 жыл бұрын

Rf is rf is rf ... GMRS (ham 70cm) Murs? (Ham 2m) CB (ham 10m). Just enjoy your hobby and QSY the QRM. 73

Kevin, I wouldn't worry about getting beat up on the comments. It was an experiment and it was a success in that you found out it didn't work as you hoped it would. good video!

Nice video on the comparing the 2 antennas. If you have the time I think comparing a double bazooka & dipole would be interesting to see.

Yo Kevin!: Again GREAT video! After your 1st experiments with a folded dipole, I was not surprised that it had a lower noise floor. Orientation differences likely do come into play. Shame you didn't walk around with the end of the dipole in hand, listening to radio output as you moved. That would've been interesting. Don't worry about QRZ, there are naer'do wells that LOVE to just TROLL newsgroups. : ) I LOOK FORWARD to your next video! de seeker/Jeff WA7LFP

Hi Kevin, your noise floor test at minute 6 maybe showed the folded antenna sensing the heterodyne much more clearly! M0HXQ

There will be interaction between the two antennas in the orientation you have them. The shorter antenna (higher resonant frequency) might tend to act as a director its direction, and the longer antenna (lower resonant frequency) might tend to act as a reflector in opposition to it's direction. A more fair test would be to orient them end to end off the same support pole to reduce or eliminate interaction between the two. That said, I appreciate your video series, because you are approaching the hobby in the way it was intended, as a hobby, and trying new and different techniques is what it is about. Keep up the good work!

@BubbaWarbucks

5 жыл бұрын

But even putting them end to end in your configuration wouldn't be completely fair, since they are installed as slopers, and each antenna would favor the direction of its slope.

Quiet in the desert ? Sounds like a slice of paradise to me.

Just a thought: If you are getting balun loss then the cross bound rejection might not be as good with a proper balun. Folded is still my preferred antenna on the lower bands just because of the bandwidth.

It amazing at the negativity of people. I really like your videos. You are just like the regular guy just having fun with the hobby. Every Ham around me is the look down your nose I'm better than you snob do-gooders with the best of the best radio gear and manufactured antennas. I too have ruined a many a pieces of wire trying stuff. If you are enjoying yourself and still having fun let it rip. All the do-gooders, haters and trolls can blow it out their a$$es. Good job Kevin!!!!!!

There is most likely some interaction between your two aerials, which gives different results to each. Also does the switch ground the unused aerial. I think you need to test just one at a time, over a set distance to a marker beacon.

I built some 49:1 end fed half wave ununs out of -43 and -2 mix cores and made 2 of each and rigged them up back to back and measured the power in vs power out and the 43 mix cores had 3-6dB loss while with the -2 (powdered iron) cores I could barely measure any power getting through the transformers and the SWR was sky high. I think this means -2 cores might be better suited to use as common mode chokes rather than transformers. I've not tried 63 mix cores yet but I intend to get a few and play around with the. Core material selection is a bit of a mystery to me but if the core soaks up the energy and gets warm rather than acting as a good transformer then I'd reason that's what you'd want a choke to do.

Do you have a different balun to try? I would be curious to see those results...thanks for the video and all the experiments that you do whether or not if they work. After all they are experiments...

Here's an interesting one you could try - seeing as you have a location where you seem to be able to do anything! (And have an enviously low noise floor - mine is horrible). A double Zepp. ~I've made one for 40, but I have no means of comparison as I can't put both antennas up at the same time. Basically its two half-wave horizontal wires, fed in the middle by a pair of parallel wires (450R ladder will do) a quarter wave long. These are shorted together at the bottom, then you use your analyser to find the 50R point a distance up from the bottom. Mine is about 4' up. No tuner needed, no balun (although a 1:1 is recommended) and in theory it gives about 3dB gain over a dipole. Some folks say its better to use 5/8 horizontals.

Hi Kevin , would be great to see a side by side comparison of a T2FD vs a dipole for a future video.

@loughkb

Жыл бұрын

A terminated folded dipole is very low Q and broad banded, but that always comes at a price. In this case, the terminating resistor sucks up some of the power, converting it to heat. They're great antennas for applications where simple very broad band operation is required, like military applications. But not going to be a high performance option.

@mrtechie6810

Ай бұрын

​@@loughkbwhat if you want a unidirectional antenna? Can the termination help?

@loughkb

Ай бұрын

@@mrtechie6810 clarify what you mean by unidirectional

Hi Kevin, Good comparison. As a suggestion, perhaps a project to build a 2 or 3 position remote antenna switch! Done in a 3D printed case, relays & protection circuit. That way it's quicker & easier than constantly running outside & back. 73 - John - N7GHZ

Kevin, I would like to see James transmit on the same band as you, with you on your Magnetic Loop and James about 100 Khz up on the same band

Very well presented experiment. Don't worry about QRZ... a sizeable minority on their forums just live each day for .... the forum. Stick at the experiments it's all good. 73

Just my experiment, I was able to change the noise level by changing height and a little twist in the antenna. Also change the reception quality with a little difference in angle of one leg. I picked up less interference by dropping one leg about 4. feet. Not sure why but it did work. not sure if it makes any difference I also added a 6 turn open air coil in feed line just below the feed pint. Its working too well to experiment with. Don't fix whats not broke LOL

Interesting tests. I've been wondering if baluns significantly affect antenna performance myself. I used to run a 1:1 on my (regular) dipole but took it off when it got water logged and ruined. My antenna really came to life after I removed it but at the time I thought it was because the balun had slowly degraded over time. Recently, I've wondered if the balun was just inefficient all along, even when it was new and dry based on some recent observation of antenna performance at a few of my friends stations. I've considered doing a balun/no balun comparison on my antenna and making a video about it but I'm not sure when I'd get to it between work and other things going on around here. Thanks for taking us through your test - 73!

@loughkb

5 жыл бұрын

Yeah, I'm sure the balun is a factor being that I didn't use the optimal core material. I'll re-visit it in the future when I get type 43 cores to rewind it with.

We wouldn't have lightbulbs without failed experiments, sheesh people lighten up. Another great video. Maybe you found a future project video...remote antenna switch so you don't have to run outside. I wonder how the folded dipole would work if you brought the ends in close to the middle (almost like 2 capital E's or capital sigmas), for space purposes?

Need to get one end up at least 50ft off the ground min (hot end),slope it 35-40degrees Ive found for best performance, this also applies to the off centred dipoles (OCD) I used a 4:1 or 6:1 balun ,NO terminator resistor for single band use If use the terminator resistor (non inductive type) heatsink it and place opposite balun side, you will get broadband HF dipole (at reduced efficiency) ,it can be fed ladder line 200ohms down to radio with balun 4:1 . Folded dipoles tend too be a lot quieter on HF,but getting them high of the ground has less ground affect with Ariel and have more accurate VSWR reading, and wont need lossy ATU's! Great vid,dont worry so much on comments, its experimentation and learning curves NOT life critical MIL HF or Commercial comms your doing, where live depends on it! Its Amateur Hobby radio for gods sake at end of day, some take this hobby far to serious and need to chill out. Glad your having radio fun with this ariel type, used extensively in the commercial world by the way. some handy ham info here maybe of some use to you. www.nonstopsystems.com/radio/pdf-ant/antenna-article-ttfd-3bvw.pdf www.nonstopsystems.com/radio/frank_radio_antenna_folded_dipole.htm#construction 73's Rob

Wood the folded dipole performance be better if you used ladder line as opposed to the window line? Just a thought.

Love the intro Kevin. De M0KTY

Welcome to the world of research. 90%+ failure or dead ends due to technical issues, experimental design "flaws" which corrupt data, etc. But I think you have some valid and useful conclusions within the controls of your study.

Thank you. I have used dipoles, but not folded dipoles. May give it a shot. N0QFT, Glen

Hi Kevin. I personally prefer standard dipoles as have found there performance generally out performs folded dipoles. Thanks for the video. 73 Ian G7HFS/PA3IKH

Another experiment could be to compare a inverted V to a normal dipole. I use a 6m dipole in my attic for North South I run it along the roof peak. For East West I have to turn it 90 degs and use it as an inverted V along the ceiling of the attic. Interesting as a dipole it does better at getting out North and South then as the Inverted V. Which I think is sort of odd considering as the dipole it has the wire running east and west. (I might try and make a video about it someday. But I don't have a VNA or antenna analyzer.)

Bit saddened to see the folded dipole performance was not as good. Was cheering for it to be better since I was expecting it to have lower noise floor. Living in an apartment though either antenna not possible for me, pretty much limited to halfwave endfed or random wire. Sometimes I get questions from neighbors with the endfed wires, just wait for that neighbor to move and try again. Interest in the folded dipole comes to me when wanting to operate portable in the park. Thanks for your presentation. 73 de WB0RSZ

@loughkb

5 жыл бұрын

Well, as I mentioned, I'll be revisiting this in the future when I re-wind the balun with type 43 cores.

Nice experiment. Folded dipole seems to have a bit more loss. Makes the bandwidth greater and reduces performance and overload a bit. Consumes more wire, harder to tune, more weight in the air, harder to roll up. Alan w6akb

I'm curious how much antenna orientation came into play. Have you tried to compare over an extended period with different stations? Be care when transmitting too close to another antenna that's close in proximity and wavelength. I wiped out the front end of a radio once this way. I've started using a watt meter terminated into a 50 ohm dummy load to check. The radio that got damaged was a two meter with a 5/8th wave and the offending transmitter was a GE Master 2 with 50 watts into a 1/4 wave at 52.39 Mhz. To be fair the antennas were both on opposite sides of my truck of my car only about 3 feet apart and VERY close to the same length. It was sending 5 watts into the rx antenna using a watt meter and a 50 ohm dummy load. I was young and dumb! Thanks and 73's!

The balun is probably not optimized as you said. Hence the lower signal strength and lower cross band interference.. Maybe a better balun would result in the same performance?

Hello Kelvin, as I know Iron poder core like Txxx-2 works fine for making inductors on LPF, ATUs etc since Ferrit core like FTxxx-43 is a better aplication for HF antena balun, transformers etc. Did you choose the iron poder core for any reason?

@loughkb

5 жыл бұрын

Availability. I had them on hand.

Fun and interesting vid Kevin. Thanks. I expect that every one of your test metrics (great ones, btw) was mostly a comparison of the two antenna orientations - and that actual antenna performance (other than B/W) was almost exactly the same. Close-in front end overload is drastically affected by polarization and orientation differences. Screw the miserable QRZ posters. They're bored I guess. In my opinion, your previous window-line-as-a-radiator experiment - that's real ham radio and is how we got to where we are today. PS- load your balun with a non ind resistor and sweep it at your freq of interest and you'll see if your core mix is an issue. 73 OM

@loughkb

5 жыл бұрын

Thanks. I did sweep the balun with a 200ohm carbon resistor on the output and it was almost flat 50 ohms. However, once under power and load, the core material can have a more dramatic effect. A more solid core like a type 43 is most certainly a better choice when power is involved.

@n8nkqrp595

5 жыл бұрын

Yep. I just wound 7-tap ununs for end-feds on type 43 and they are all fine thruough 20m. I wound them on 3 types: FT120-43, FT140-43 and FT-240-43. I tested them at various Z transformations, load-side SWR variations, and power levels. In each cofiguration, I transmitted for 3 min key-down then measured core temp. Surprising what I found. I would 'em with taps for 4, 9, 16, 36, 49, 64 and 75:1 ratios. 73 and thanks for all the intersting stuff as you go forth with your travels, experiences and discoveries

QRZombies always trying to rain on parades with the "....well actually...." Great content! don't listen to the haters

Hi Kevin, What was your overall lenght of the folded dipole? Nice experiment....learn everyday.

@loughkb

5 жыл бұрын

A bit under 33 feet.

In past research I have been told that being a balanced antenna a folded dipole should have a balanced feed; either window line or coax with a balun. Have you tried that and if so did you find the results any different. Since you didn't mention it I assume you have not had the chance to do that. Nice video, thanks!

@loughkb

5 жыл бұрын

I talked a bit about the balun in the video. It was a 4:1 current type, but wound on type 2 cores which are not optimal for HF. As I mentioned toward the end, I plan on revisiting this experiment when I get the better cores to rewind the balun with.

sorry if my spelling is not great but if you want you can speak dutch with me . in dutch we speak of the symetric feedline as a ladderlijn (dutch) and the balun is 300 ohms to 50 ohms .

Standard dipole vs folded dipole in the same orientation and at the same height, I would not expect to see any difference in the radiation pattern. The only difference I would expect would be a widening of bandwidth. If using the same wire for both the antennas I would also expect to see a slightly higher loss in the folded dipole because of the extra wire used and there being two current nodes (where the feeder connects and 180deg away on the other side where the wire is unbroken). This extra loss would be VERY hard to measure in the tests you have performed. The main advantage of the folded dipole is of course the wider bandwidth. The other advantage, not often noted by amateurs is the fact that the folded dipole can be electrically connected to the support structure, 180deg away from the feedpoint. Especially on vhf, the higher feed point impedance may be an advantage in a stacked array. You could parallel 4 folded dipoles and end up with a feed impedance of 75ohms. Great to see people doing hands on experimentation! Chris, UK (Radio addict.)

Isn’t this hobby fun? Once you have done even a “bad” experiment you have learned something. Interestingly, your brain will keep ruminating about this one and some morning you may wake up and the light will go on with the “why” it didn’t work or another idea will come for a better experiment. Happens to me quite frequently. Keep on “trucking” or motor homing..... Dave K8WPE

type 2 iron powder material perfect for straight inductors (for filters) on HF but its u factor not nearly high enough for balun use where you REALLY need the higher u of the ferrites (type 43 mix & that ilk). ... the type 2 material transformer impedance will not be high enough... especially for 300 ohm 4:1 use. This may have accounted for some of the folded dipole reduced performance.

How long is each side of the folded dipole? What was the balun, number of turns, core size?

@loughkb

5 жыл бұрын

Each leg was just over 16 feet. The balun is a 4:1 current type. I talked about the cores and how they're not the optimal type. But the VNA when connected at the balun showed right about 50 ohms across the band. The cyan plot in the graph I showed.

Nothing said about the feed. Folded dipoles have a different impedance than the standard dipole ( 50 ohms ). You need to match a folded to your transmission line.

I made the same comparison. except my two 20 meter antennas were inverted V configuration. My 4:1 balun was a Amidon 240-125 which is a Ft=240-61 core. I used twisted wire and not the 14 ga. wire that comes with the kit. The balun worked great. My results were the same as Kevin's. The folded ALWAYS had less noise. Transmit was a different sorry. Maybe I can figure out a way to transmit on one and receive on the other ! hhhmmmm

In a desert environment where the natural band noise level is very low anyway, there wont be much of a change in noise level between both Dipoles. But in an urban environment where electrical noise may be more of a problem, there should be more of a noticeable difference on the folded Dipole. Height matters of course, so the higher a Dipole is erected the better it will perform in terms of gain. Try raising the folded Dipole to 60ft, and then you should notice a difference.

Your sloper configuration will skew the power & receive in the direction of the slope... put them up as inverted V for a couple days each on whispr and see what the plots look like. Maybe McGiver a way to raise one and lower the other to A/B test them...again as inverted Vs Thanks for the effort none the less Kevin!

@loughkb

5 жыл бұрын

Yeah, I know. I do plan on eventually revisiting after I get better cores for the balun on the folded. I mentioned in the video that the type I had on hand wasn't optimal, but a few comments still beat me up about it.

It's like when I used to race flattrack......sometimes the only way I could find out how fast I could go was to find out how fast I couldn't go....lol

Interesting comparison. Let us know when you change out baluns. Thanks for sharing the experiment with us. :)👍

The 7300 is the worse rig for splatter. Found that out in field day. The better the antenna. The worse it is. Window line is awful for longevity. Try testing a 20m vertical delta vs the 20m center fed dipole. Always enjoy the vids man.

I have done a/b comparisons between verticals, loops, sloping dipoles, etc. and the results have been baffling at times. The antenna gurus blame it on the hardware, since EZNEC is infallible. Maybe it is with an ideal text book antenna environment, but that's not reality. With your installation there could be interaction between the dipoles. Even at right angles there should be a full wavelength separation to minimize interaction. Dropping one dipole to the ground would take time, but its the only way to be certain. Experimentation is what ham radio is all about IMO.

Keep experimenting. Maybe try a caged dipole, say a five wire cage on 40m.

@denelson83

3 жыл бұрын

That would certainly be more broadband.

The problem is the feedline. The type 2 cores should be good up to 20 meters, but the 2:1 balun takes the 300 Ohm antenna to 75. Ohms NOT 50. Ohms (RG-59) The source (transmitter) need not match the feedline! So over the last two years my opinion has not changed, He definitely compared his two antenna, but not two properly operating antenna. I am positive that these two antennas should have been oriented at 180. Degrees to each other so angular differences would not exist. And the test would have the minimum interaction. (as in any shootout) I am about to hang a 20 meter folded dipole on top of my house and I will use a 75 Ohm to 50 Ohm (1.5:1) transformer. I did see 50 Ohms on the miniVNA and the impedance was greatly flatter and wider than the simple dipole. He did not mention how much higher one was to the other and which. Ron W4BIN

@stargazer7644

6 ай бұрын

He literally showed you the impedance of the antenna on the VNA. It isn't 75 ohms.

All these outcomes are already known decades ago. That is the thing. Ham is ancient history, but still enjoyed for hobby use by many.

I am amazed that he tested a 300 Ohm antenna with a 200 Ohm feed line. I would have used 300 Ohm TV antenna twinlead to the back of the radio and then the balun. (as I always have) The way he did it he should have used 75 Ohm coax to the balun. (RG59) I love my miniVNA-Pro. When I test antennas I am most concerned with return loss. RL

@loughkb

4 жыл бұрын

When I first built the 40 meter version of this folded dipole, I scanned the antenna directly at the feed point with the VNA and read 214 ohms at the resonant frequency. I think it was lower due to the closer spacing of the elements in this window line. So the 4:1 was the correct choice. With this antenna and the 4:1, the VNA showed around 52 ohms at resonance.

I did not see a clear picture of your impedance matching...

"unfortunately a low noise floor in the desert" hi hi, I wish

And If this would be a Loop, than there is at least a Possibility, that this Antenna would be now vertically polarized.. :/ But I do not know, if the same happens to a folded Dipole as well..

Great Video mate as always...As for the Nay Sayers I bet most if not all of them have never had or used a soldering iron let alone made an educational informative video..Geez they have probably never even made there own Antennas most likely bought very expensive commercial made rubbish and they are probably convinced that there's is the best because it has an expensive sounding name..Just ignore them Kev and keep up the FB work. 73 Steve M0BFM

Kevin try using the FD as inverted V

@loughkb

5 жыл бұрын

When I get type 43 cores and rewind the balun, I'll be putting it back up. I'll do an inv V on that go. For both antennas.

THANK YOU. SO THE ANSWER IS FOLDED IS A NECCITY NOT A WANT.

But you'll have a severe mismatch at the feed point of the folded dipole, as its centre impedance is close to 300R. You need to feed it with a 6:1 balun, or with 300R line then a balun or balanced ATU at the radio. That's probably why the folded dipole didn't perform well on RX and TX. I have one here on 40m, fed with 300R bad feeder - it outperforms a standard dipole both in signal and background noise.

@loughkb

5 жыл бұрын

If you look at the VNA scan I provided, you'll see that the impedance, (cyan plot), on the low side hovered right about at 50 ohms. It was providing a proper match.

@Rick-se5qm

5 жыл бұрын

@@loughkb Where was the VNA scan tool terminated, at the dipole feed point or the radio? If at the radio the feed line has influence over the Z readings.

@loughkb

5 жыл бұрын

I hang the VNA at the feed point, hoist the antenna and run the scan. The MiniVNA is very light and communicates back to the software via bluetooth.

@andylinton2798

5 жыл бұрын

Kevin Loughin there’s no way a folded dipole has a feed point impedance of 50R. It just doesn’t. Look it up. And in your video I see the coax just joined to the dipole centre. I promise you, it’s 300R there, a touch less in fact.

@loughkb

5 жыл бұрын

That's right, it was closer to 220 ohms. That's why I used a 4:1 balun at the feed point. I talked about the balun in the video.

Check out the W0QE channel, he has extensively tested different kinds of materials and topologies for baluns.

@loughkb

5 жыл бұрын

Thanks, will do.

50 ohm coax directly to a 300 ohm is a nobrainer, and a folded dipole will be ineffective on the uneven harmonics.

Need a 4:1 balun with the folded dipole, it'll be about 200 ohms characteristic impedance..

@loughkb

3 жыл бұрын

That's why it has one on it.

6 to 1 balun or 9to1 balun It will work better. Nice experiment . 73

@loughkb

5 жыл бұрын

With the 4:1, I saw right about 50 ohms on the low side all across the band. It was providing a good match.

You do realize the antennas are directional.

@loughkb

5 жыл бұрын

That's what I said in the video.

@ed-jf3xh

5 жыл бұрын

@@loughkb My apologies, I didn't hear that part.I withdraw my statement.

For this test to be useful, the heights would have to be the same

From the Photo of the Folded Dipole I noticed something (maybe a bit) strange. At least _maybe_ it is strange.. Every folded Dipole that I have seen so far, is mounted in a Way, that the two "Lines" of the folded Dipole are _above_ each other, ( Also Your 40m Version of a folded Dipole was mounted this Way, at least at the Feed Point. As far as I could see it at the Photos..) but at this Photo for this 20 m folded Dipole, the Antenna is not mounted this Way.. The two "Lines" are more like "Side by Side".. Maybe this _could_ also change something. But I am not sure, bc. again.. no folded Dipole, that I have seen so far was mounted this Way.. Maybe this could change the folded Dipole to transmit / receive more in the Direction directly into the Sky/Earth, but again, I do not know.. It is also possible, that it changes nothing.. Otherwise it could be the Balun.. or the (different) Directions of the two Antennas..

@loughkb

5 жыл бұрын

I don't think it makes much of a difference as both conductors in a folded dipole have basically the same voltage and current curves. Both the 40 and 20 meter version tended to twist up helically anyway. On the 40 version, in high wind, it was oscillating, coiling up and uncoiling rapidly. For fun, I hooked up the vna and watched the impedance and swr in real time. It stayed rock steady. So the coiling didn't seem to matter.

@andylinton2798

5 жыл бұрын

@@loughkb Correct, it doesn't matter - even if the ladder line twists a bit. I suspect your results though are skewed by the antennas being on different bearings.

@DE-iv8if

5 жыл бұрын

@@loughkb - I never made a Folded Dipole. But I think I will try to make One and test if it at least changes something, when one of the two Conductors is of a different Diameter than the other. But (at least) by now, the Folded Dipole simply (more or less) looks _almost_ like a regular Dipole.. just with a different Impedance. (And maybe with a little bit less Background Noise). So it also should work as good as a regular Dipole. (more or less).

you cant use a regular latherline for hf folded dipole must have a spacing of min of 10 inch

@chuckk5358

5 жыл бұрын

Latherline.....is that like soap on a rope?

@loughkb

5 жыл бұрын

Yeah, you can. In the 40 meter version I had great success with the antenna, excellent signal reports as well.

haters gonna hate, if they care that much then they should make a KZread channel.

I’m new to Amateur Radio and about to take my General Exam and will pass, as I have been studying a great deal. I have not seen any mention of a “folded dipole”. Can anyone tell me what is the physical difference is? Thank you.

@bashcoder

5 жыл бұрын

Actually there is a question in the General exam pool regarding folded dipoles, but it’s a very incidental question. [ G9 A13 Q: “What would be the SWR if you feed a folded dipole antenna that has a 300-ohm feed- point impedance with 50-ohm coaxial cable?” A: 6:1 ]

Check out Palomar Engineering for the right ferrite core material and size per application. palomar-engineers.com/ferrite-products/ferrite-cores/ferrite-mix-selection

Your folded dipole is much to narrow. I run a folded dipole vertically, for 27 mhz. as a diamond shape, it is 1.2m wide at center, and 5,5 meters tall. It blows away , my quad loop, and vertical dipoles. It is the best antenna I have ever used on 27mhz. I have run, j-poles, moxons, quads, 1/4 verticals, the diamond, folded dipole just works magic, have it 50 feet to the top. If you run a dipole calculator, and get your width right I think you will find your folded dipole will blow your dipole, right out of the water. For a diamond dipole, take the calculated width and double it for width. You will not be sorry. This is my favorite antenna on 27 mhz.

@pixotica

4 жыл бұрын

You will need a 4:1 balun at the feed point, tuner is not the answer, 4:1 right at the feed for efficiency. I use a coax balun, ie 1/2 wavelength X velocity factor of coax.

@stargazer7644

6 ай бұрын

That's not a folded dipole, that's a rhombic antenna.

Desense reduction doesn't really matter too much if you can't hear anything on the folded dipole to begin with. Look's like it's back to the drawing board Kevin.

Hope your enjoying something in the land of nowhere. ✌️

@loughkb

5 жыл бұрын

I'm enjoying the relative peace and quiet. The evenings are wonderful.

@charlesschindler1971

5 жыл бұрын

Kevin Loughin - O.K. enjoy. ✌️

The relevance is only pertinent to your antennas, which are irrelevant to anyone else's.

@loughkb

2 жыл бұрын

Obviously.

Your comparison is not sufficiently scientific and tightly controlled, so you should average your results over some long period of time, in order to draw any conclusions. Your balun is indeed an unknown variable!

They are oriented in different directions. Therefore the patterns are different. How can you draw conclusions this way? Your core was a -2 powdered iron? Normally ferrite is used for baluns, isn't it? If the balun has loss, it will contribute to the antenna appearing to be broadband. If you are going to be making signal comparisons you should be doing them instantaneously, flipping back and forth, and do lots and lots of them. Walking outside and switching, with QSB that is always present, doesn't mean anything. I hope no one who watches this video draws any conclusions about either of these antennas.

@loughkb

5 жыл бұрын

Yeah, I talked about all of these things in the video.

Sorry but "yawn".