Compact, Quick HF Antenna: Wire Mesh + Magnet Mount Whip

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My friend Tom VA3WBA was impressed by others using chicken wire with HF vertical ham radio antennas, so he talked me into trying the system he put together (modified Workman magnet mount, MFJ 1979 whip, a metal pie plate and some wire mesh). Check out the video to see the results.
After this video was posted, Tom VA3WBA asked me to add the following text:
"In the video I say (or we say) " magnetic coupling" There is no magnetic coupling . Mechanically the antenna is installed with a magnet however the coupling is capacitive. The bottom surface of the magnetic mount acts as a capacitor (one side of it to be exact the other side is the roof of the car it is mounted to)".

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Опубликовано:

14 янв 2024

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Комментарии : 28

@KB9VBRAntennas 5 месяцев назад

Nice demonstration. After making several thousand contacts this way, I've been so impressed with how the window screen or faraday cloth works. It has become a permanent part of my antenna kit.

@OutdoorsOnTheAir 5 месяцев назад

You were the first one I saw on YT to use this technique, Michael! Thank you for popularizing it.

@KU9L 5 месяцев назад

That matches the results I have obtained with two 48"x84" aluminum window screens and also a Faraday cloth of slightly smaller dimensions. Eventually I will make a video on it, too. I have used a picnic table clamp with the same MFJ-1979 & & a 17" alligator jumper to the aluminum screen in the ground as well with good results. Thanks for sharing, when my XYL Ham wife's arm recovers from her spiral fracture of the Humorous I will get back to the fun! The window screen typically achieved better VSWR bandwidth than using 2 counterpoise radials, elevated or on the ground. I have the exact same AA-30 antenna analyzer. Cheers, Davey --KU9L

@watersstanton 5 месяцев назад

Mag mount will have tiny capacity to wire because most of the surface below the mount is “air.” Onlt a direct connection will work - as you have found.

@davidsradioroom9678 5 месяцев назад

What a cool experiment! There is also Faraday cloth available now. I wonder how well that would work instead of chicken wire.

@fredbos5997 5 месяцев назад

Great, to make contact with a magnetic foot on a chickenwire mesh! Nice video. It must have been cold. No snow, but I believe you will have snow soon. 73, Fred PA0TSE

@ryank5tar 5 месяцев назад

wow Tom, Thanks for the magnetic coupling explanation and the difference in HF coupling.

@radioastronomy2001 5 месяцев назад

The coupling was really capacitive not magnetic. The mechanical mounting was magnetic. The bottom of the magnetic mount acts as one part of the capacitor the other part would be the roof of the car.

@W4TRI 5 месяцев назад

There is a good non stick coating all over that pan. Better than the paint on most cars.

@harryr.6744 5 месяцев назад

The metal screen increases the capacitance between the whip and the ground return. The use of radial wires as counterpoise has less capacitance. this is why the wire mesh works with a smaller surface area. I would have liked to have seen the wire mesh removed and the pie plate on the ground, added to the experiments. In the experiment that was done, it looks like the coax ground is the counterpoise and is resonant at a higher frequency. Hence the wire mesh lowers the resonant frequency. The mag mount works by capacitance coupling to the ground when on a metal surface such as an auto body. There is no magnetic coupling as said in the video. Finally, curious as to what would happen if a choke coil is placed at the connection to the magnet mount.

@radioastronomy2001 5 месяцев назад

Thank you for your comment. You are 100% right. There is no magnetic coupling. I do not know why I said this. Perhaps because it was a magnetic mount :-) . The "mounting" was magnetic but coupling was capacitive. It would be interesting to use a "hair pin" style match to is it the SWR could be improved. Also, it could affect noise created by the static charge collected by the whip itself. I have no idea if it would make any difference, I never tried it. I have seen small coils on car installations. Last but not least, I wanted to have a choke but I decided not to. I use this mount on the car and the choke would be one more thing that could make a dent. I would have to wrap it in a piece of bubble wrap or something soft. Then it would be difficult to store, since the cable can not be detached. Anyway, tons or room for experimentation.

@ThumpMaster6 2 месяца назад

I wonder what would happen if you moved the pizza pan/mag mount near one end of the hardware cloth? Would you see some measurable 'directionality' toward the long end of the mesh, as you do with a series of radial wires not evenly distributed around the vertical element? Great experiment, and a fantastic set up where parks will not let you penetrate the ground with a stake or rod. 'Could be interesting to try with Walt K4OGO's 'Coastal 20' or other verticals...and, yes, thanks to KB9VBR Michael for bringing back this old-school technique for a fast-to-deploy ground plane. 73 de KN4HGI Al/Thumpy

@OutdoorsOnTheAir 2 месяца назад

Interesting question! 73 from VE3TWM.

@dewindoethdwl2798 5 месяцев назад

Nice & simple experiment. Counterpoint wires are a pain but this could make it a lot simpler on flat ground, like a campsite.

@amateurradiohf 2 месяца назад

EXCELLENT SWR DESIGN CHICKEN WIRE GROUND SYSTEM. A+++++++++++++++++++++++

@billmcilwee566 4 месяца назад

Informative and even scientific. Thanks and 73, KF0NNQ.

@OutdoorsOnTheAir 4 месяца назад

On behalf of my friend Tom VA3WBA, thank you and 73 from VE3TWM!

@yankee7664 5 месяцев назад

look's like a good idea...i have a 9 Hf band's Outback 2000 mobile antenna in my second floor apartment that i use as a temporary base antenna on the balcony...the Swr is always a problem whit out a good ground plane...i will do some experiment whit the chicken wire and the magnet mount on a flat small space 9' x 3' long....and see if i can use 10m, 12m, 15m, and 20m... also if it works on 30m, 40m and 80m whit a longer chicken wire ( i have 6m but not in my icon hf radio maybe i can make some test whit my 6m Fm/Am 2w Ht )...for the Swr test i will use a rig expert analyzer......73's good Dx's.....WP4EFM

@Philip-KA4KOE 5 месяцев назад

There is some credence to using a ground screen for 20 and up. Below that at least 100 SF minimum.

@jeffdhartman 5 месяцев назад

What does SF stand for?

@ben2e0omr 5 месяцев назад

I'm just guessing,sf = square feet . @@jeffdhartman

@radioastronomy2001 5 месяцев назад

Thank you for your comment. I have 80m hamstick and I would like to try it. It does not perform well when magnet mounted to the car's roof. Probably there is not enough capacity for such a low frequency. I hope to that the chicken wire will provide better results hence it does depend on capacitive coupling.

@joekrepps 5 месяцев назад

Makes perfect sense. As a mobile operator, I have a Yaesu ATAS-120A on a 3 magnet mount, on top of my Outback wagon. Nothing grounded or bonded yet. I’m sure there’s a huge correlation between a big piece of chicken wire and a station wagon roof. I’m 64/100 towards Mobile DXCC in almost 2 years. Just 5w-50w from a FT-891, SSB. A chicken wire ground plane would/should work really well for me at home too. We live in the middle of a row of 6 rental condos so antenna options are “limited”. If I could mount a few Hamsticks on a big piece of chicken wire, I might be able to do quick band changes…a poor man’s DX Commander

@malcolm2587 5 месяцев назад

That appears to be half inch hardware cloth and not chicken wire

@radioastronomy2001 5 месяцев назад

You right. I was not aware of the existence of the "hardware cloth" till now. I purchased it at Lowes and the sales person called it "chicken wire" and sold it to me as such. Thank you. I just learned something.

@scottdunbar4898 5 месяцев назад

Is the pie pan teflon coated? If so, the teflon might be acting as an insulator hence the need for the wire jumper.

@radioastronomy2001 5 месяцев назад

Thank you for your comment. The pie pan is painted with some sort of nonconductive paint. It does not matter hence the coupling is capacitive. We use the pan to provide needed mechanical stability over anything else. The effectiveness of the capacitive coupling is dictated by the size of two surfaces (and a distance between them). In this case the size of the surface of the mount itself and the area of chicken wire under it. Which is not much... Normally the roof of the car provides much larger surface and acts as a part of the antenna system. The jumper cable runs between the shield of the coax cable and the chicken wire. (the mount is modified and we can do it) Effectively eliminating need for the capacitive coupling . As such the jumper cable does not even touch the pie pan.