HF Variable Frequency Vertical Antenna -Help us Refine it and join in the Fun! | Ham Radio

Peter G3OJV, has created a new HF Variable Frequency Vertical Antenna. You are invited to make suggestions and refinements to this design. So get out and start twisting some wires! Link this video to fellow Hams so they can join in and experiment.
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[@StevenLAllen]

I've taken a 17' whip antenna and put it on a tripod. I took a 9:1 balun and attached it to the 17' whip with an 18.5 foot wire to the balun. This makes the antenna 35.5 feet which is an excellent random length for the balun (unun). I have grounded the other side of the balun to my ground stake in the yard with a 22 ft wire. The coax to the radio is attached to the balun. Takes 10 minutes to set up. I can tune on my radio 10 to 80 meters. No external tuner used. If I lower the whip to the lowest length, I tune on 6 meters. After tuning on the radio, my SWR is 1:1. I have made contacts to Japan, Russia, US eastcoast, Hawaii, Canada, and Mexico on 15, 20, and 40 meters. I'm in Southern California, USA. I just recently demo'd this design with my local club. It works very well for me. Very nice video. I will have to try the 49:1 balun on my rig. 73 KJ6ZBU

[@watersstanton]

Hi there, and thanks for sharing. Ham radio is all about trying to make the best of situations we find ourselves. Well done.

[@StevenLAllen]

Thank you. The MAGIC happens when you can collaborate and share. Thank you for your MAGIC. I have watched many of you videos. 73

[@ricktighe191]

A "shorting bar" could be added to the end of the variable capacitor's travel to eliminate the need for a separate shorting link. An insulated shaft, stepper motor and Arduino would be another "nice" addition.

[@LeopardAppaloosa755]

This is wild. I have an EFHW set up as a sloping L in my yard. Last week I was trying to figure out what could be done to expand the frequency range. I was thinking something along the lines of a coil - like the JPC-12. And bang! Here is your video! The variable capacitor is much more user friendly than the shorting system of the JPC-12. If the variable capacitor could be set up next to the radio, then the various bands could be dialed in without treking out into the weather. Anyway, Peter, you are definitely onto something! Love your videos. Always get my mind going. Thanks!

[@Gw0wvl]

I've been using my homemade EFHW as an inverted L for quite some time , It works quite well for me at this low in height location .

[@ehayes5217]

ur modification, making it a switchable, tri band antenna, excellent!👍😃🇺🇸

[@johnrees44..G4EIJ]

So interesting, Peter.. Good to get back to the original ethos of ham radio.. Also good to see a “professional amateur”😊 using scraps of sticky tape and odd pieces of wire just like the bits of tape and wire in my shed!! hi…Great video, Peter.. Lots of inspirational stuff for us to think about.. Many thanks..73..G4EIJ

[@watersstanton]

Glad you enjoyed it Yes, bits and pieces that were to hand!

[@3dQRP]

Great to see your experiments, Pete. The evolution of wire antennas is fascinating, particularly when you consider they all started with a bit of wire related to a wavelength (or not!). This antenna has many similarities to the W3EDP which itself is a development of the half-Zepp. And the EFHW is a simplified half-Zepp. The j-pole….. I’m intrigued and will be trying this myself.

[@3dQRP]

The ‘original’ W3EDP

[@watersstanton]

Interesting! 73 Peter.

[@basshorseman998]

More ideas to consider Peter, Thank you

[@watersstanton]

My pleasure.

[@ChaplainDaveSparks]

I was originally thinking about a length of wire attached to a helium- (or hydrogen) filled balloon. You could raise or lower the height of the balloon to choose a resonant frequency. If not … a tall non-conductive flag pole. No, the flag pole is not the antenna. But it has a pulley at the top with a length of rope attached to a thin antenna wire. Pulling on the rope will raise a varying length of wire. *73 de AF6AS in **_“DM13”_** land*

[@CamilleCullen-ow6qj]

Great video, many thanks!!! Robert K5TPC

[@crosscountrywireless]

Years ago when the then new WARC bands were released I used a capacitor at the base of a 5 m quarter wave vertical for 20 m to make it tune on 17 m and 15 m. It worked very well. I've now got a 7.2 m vertical for 30 m so I'll test it with a variable capacitor. 73 Chris G4HYG

[@watersstanton]

Yes a series capacitor will raise the resonant frequency.

[@sussexphil4236]

Take care Peter. It looks like that 11kV power line is within the falling radius of your pole !!

[@watersstanton]

Optical illusion. The camera lies!

[@rogerbirchall9037]

Yes, I had a friend who killed himself erecting his ant under the power lines.in the dark . Interesting ideas Peter, I’m a big fan of the EFHW . Roger G3KMV

[@Yankee_Doodle_Stacker]

You are absolutely brilliant.

[@watersstanton]

I am just a keen ham operator.

[@tommiller1315]

Hi Peter, in the past, I have benefitted from high voltage transmission lines, parallel to my long wire antenna. Around five minutes into your video, I see these a matter of feet away from your setup. I postulate these will receive and couple to your incoming and transmitted signals, acting as part of your antenna. Mine were around 100m away, running NNE / SSW in parallel to my 50m long wire, and in 2009, I had some lovely contacts as far as Tasmania, with 100W from a Kenwood TS430S. I only thought this through recently, as I currently have an "L" shaped 10m x 10m long wire, not benefitting from the "help". Good to see your experimentation, and I will apply this idea to my 10m vertical pole, with a (random) horizontal wire, as is my normal experimental practice, when time permits.

[@watersstanton]

Interesting observation. I have only had this location for a few months. The cables produce hardly any noise and run north to south. My main tests are from home so I am happy that the results I get can be assessed fairly. Thanks for sharing. 73 Peter.

[@n0vty873]

I recently built a 60ft inverted V fed it with a 9:1 unun, center was abt 18ft high. Tuner tuned it on 80 - 6m. Two bands worked without the tuner. First time on the air with it was ft8 at 50 watts on 20m and got a quick qso with Italy from South east Iowa in the US. Did mostly listening and tuning untill I took it down and put it away. Nice little quicky antenna. Will mess with it some more later on.

[@2e0txe]

StepIR make a variable length vertical although not very portable, however Colin MM0OPX has developed his Adjustiwave antenna that is similar and works portable. For me, the DX Commander wins. Once the initial build has been done, its super quick to throw up and get on the air.

[@watersstanton]

The advantage of my system is that it is very simple to make and the variable capacitor is very efficient. It needs no guying and very fast to erect. There is also some directivity gain.

[@DL1GKC]

Nice experimentation with capacity. However, for portable operation I would rather insert a link (e.g. 2mm banana connectors) in the 20M wire to achieve resonance on 17m or any other higher band. Alternatively, one could use a variable capacitor/inductance (LC circuit; Fuchs circuit) and replace the UNUN to achieve multiband functionality. If I want to LOWER the frequency of the 2nd harmonic of a 40M EFHW to the CW part of the 20M band, I insert a short stub at the antenna output of the UNUN which acts as capacity at the feeding point. 73 de Chris DL1GKC

[@watersstanton]

Remember that links would have to be in the vertical section and would destroy radiation pattern.

[@davidbrowne1588]

Great idea, Also yes I found out testing a transformer and a length of wire cut for 10meters, it resonates at 24.7mhz, So I tested on another 49/1 and got the same then I came up with, like you say the 49/1 adds inductions It did make me think 🤔 How is the new shop It is a shame move from Portsmouth as I was close to it and grew up with them I remember getting some transistors from the shop in, north end Portsmouth when I was 15 years old, now 57, Thanks Dave

[@tommiller1315]

I wonder if you have compared your results with the same vertical (without a midpoint capacitor), fed through an ATU in the shack, close to your rig? I will be mounting a solid 30' vertical and using your idea with plastic drainpipe for support. So Peter, thank you once again for providing ideas for experimenting.

[@watersstanton]

The reason for the capacitor was to enable a short vertical to resonate on several bands. Missing out the capacitor and using an ATU at the shack end will not work.

[@migalito1955]

Very, very interesting. I did plan on installing a similar antenna for 20 meters. For near ground antennas I typically use speaker wire for the radiators that are then shorted at their far end tips, but not at the feedpoints. This creates essentially what if called a dipole would be now called a folded dipole. The spacing of speaker wire when configured this way brings the impedance up to near 50 ohms that otherwise would be lower due to proximity to the ground. Now using your capacitor placed in the middle my plan has changed. I definitely will give this a go. I noticed that you had a high voltage variable capacitor secured to the deck handrail. I am wondering if it was used to find the required capacitance for the twisted wires that form the antenna's in series capacitor? Nice experimental result....

[@watersstanton]

I will come back to that antenna in UK Spring.

[@g0fvt]

Just a random idea, if you used a small piece of RG58 or similar as a capacitor and the "gap" in the antenna had an SO239 fitted you could then make a series of different value capacitors consisting of just a PL259 and a a length of unterminated coax. I think it might be a useful addition to have a very high value resistor across the capacitor. 73

[@Stewart-HA5RV]

I was thinking the same. You could also have a multi-pole switch to select the band.

[@ehayes5217]

...& really good to see u on CW for this project (& hpe to catch u sometime)! While off topic, curious abt ur portable key (name, model, etc?) or was it something u homebrewed? Tnx!🇺🇸😃

[@alandrury9955]

Interesting idea Peter. I'm reminded of that other antenna you covered that used quarter-wave stubs to short out the loading coil. Wondering if you could somehow use a quarter-wave stub to short-circuit the capacitor when it isn't required. Although off-resonance the stub itself would appear as a capacitor. Hmmm...

[@watersstanton]

Yes I tried that but as you say the antenna sees it as a large capacitor. Thanks for your interest. 73 Peter

[@ricktighe191]

It seems like a series variable inductor could permit the frequency to be lowered

[@32_bits]

As always a good and informative video. Some ideas , using coax stubs as the cap. Adding an inductor in parrallel or series. Your cap idea with the whole antenna vertical, so no counterpoise. What swrs where you seeing?

[@watersstanton]

Typically 1.2:1 Always better than 1.5:1. 73 Peter

[@newsles2]

Is that an AI version of you in the intro? 😁Just starting with verticals now I have a DX Commander Classic pole so this is helpful, along with the others in the playlist. Thanks sir.

[@newsles2]

Only one thing though. You appear to be really close to those power lines. 😮

[@watersstanton]

They don’t produce any noise.

[@RuVi78]

For what I was able to understand with my beach english... is 5m high and the others 5m in a litlle slope to the 36:1 , thats it?

[@leroymay8156]

the variable capacitor could be realized with a rod that slides into an pipe.

[@watersstanton]

Yes a possibility. 73 Peter.

[@kiweekeith]

Hello there from Christchurch, New Zealand .... I just love watching your Very Informative Vidclips .... I have question for you ..... What is the Best / Smallest EFFECTIVE Antenna for 80m ????..... I live 'In Town' and don't have much space, so even an 'Inverted V' will be an Issue ..... :-) :-) :-) .... I have a 40m 'Long/Random' Wire antenna with an 80m Section added on the end, thru' a 110uH Choke, But this results in a Very High 'Q', giving a 'Needle Point' Resonant Band ...... Best to ALL from ChCh, NZ, Keith

[@watersstanton]

The best I have so far found is a 40m EFHW with the choke you mention. You can bend it around and even as you mov3 away from resonance, even a 5:1 VSWR still works if your inbuilt ATU will cope.

[@giovannimoretti9751]

Hi Keith, Check out the G7FEK antenna - it's only 7.2m high and about 13m wide and works on 80m, 40m and some higher banks. It's two inverted Ls - I'm using just the 80m side and it's quite broad so no worries about high Q. Although the design shows 450ohm line for the vertical, that's just because it's mechanically convenient. It can be two sloping wires. Cheers de ZL2GX

[@martinchristiansen556]

In another video I recently saw a trick used to automatically short out a loading coil in an antenna: Attach an open-ended electrical 1/4 wave length of coax in parallel with the inductor (in this case the capacitor). The stub must be a 1/4 wave on the frequency where you want the inductor (capacitor) to be shorted (here 20m band). This should work because a 1/4 wave open coax stub acts as a dead short on the designed frequency. This way the capacitor would be invisible on 20m but effective on other frequencies (here 17m). This should give you a three-band antenna that resonates on 20m, 17m and 10m without the need for any mechanical change-over. Worth a try?

[@martinchristiansen556]

Ah, I see somebody else has already pointed that one out :-)

[@watersstanton]

It does not work with a capacitor. Away from the 1/4 wave frequency the stub simply acts as an additional parallel capacitor. Tried it!

[@mariemccann5895]

Don't those HT transmission lines bother you or interfere with the antenna?

[@watersstanton]

Mo noise that I can detect!

[@johnyouel3124]

i ham looking at ainverted v on hf ihave 42ft whide and up to33ft hight whot bands can get in this john m7jby

[@MAV8865]

Hi Peter - did you have any problems with the power lines next to the antenna? - looking forward to the next video! 73 - M7MNP

[@watersstanton]

No, fortunately there is no problem. Have not checked 80m though. 73 Peter.

[@ehayes5217]

Yes, can certainly see a more permanent set-up with this configuration, especially with the variable capacitor design! Next step, a new product offering from ur company (attributable to u), then a "replacement" for the venerable G5RV perhaps; new ideas start small, then...one just never knows🤔 🇺🇸😃

[@michaelmchale1979]

That three phase is a bit of a worry...

[@dennyddg22]

Simply attach autotuner to the feed point 100$ cost in usa

[@watersstanton]

Hi voltage point and a lot more expensive!

[@zl1rdnz]

It would work even better if the feed point was at the bottom of the vertical section and the horizontal section comes from the top of the vertical section.... inverted L design

[@watersstanton]

I think you are misunderstanding the working of this antenna.

[@zl1rdnz]

Geez Peter.... that is called an "inverted L" been around for 50 years.

[@watersstanton]

You misunderstood the theme of the video I think.

[@hamshackleton]

--- ---for HF and radio operators? - You mean HF isn't used by radio operators? 🙂

[@aga5897]

Awesome ! Experiments are definitely a whole pile of Fun. So few 'amateurs' try anything anymore - just Buyers basically. ea7knw

[@GoonyMclinux]

Not us broke azz hams! My hf antenna is dollar store speaker wire and hopes and dreams. 🤣

[@aga5897]

@@GoonyMclinux That's the Spirit ! Maybe soon you'll be whacking 500W outta that speaker wire (on all bands) with a Free 'repurposed' microwave oven ! (hint hint)

[@rd4682]

​@@aga5897😂

[@colourist.]

A really enjoyable watch :) 73 de M0VFX

[@watersstanton]

Many thanks.