Ham radio: Easy and effective three band vertical without radials

[@GateKommand]

I enjoyed the vid thanks Tim. I couldn't stop looking at the CRT Telly either!

[@timg5tm941]

Ah ha!

[@PeterJavea]

Even though I can't realistically can't put this up here, I learned "a TON" of stuff here, just listening to you.... Thanks Tim

[@timg5tm941]

Thank you Peter!

[@norrinradd8952]

Not sure how you did it, but I'm glad you could see me too. Great video Tim. Worth taking notes when I watch it again.

[@timg5tm941]

No problem!

[@MikeN2MAK]

You might have inadvertently sold me a Spiderbeam 12m mast, LOL. I see a lot of value in this antenna for portable ops. I like to go out for POTA near gray line on 20m and then stick around for late shift on 40m. I know absolutely nothing about making coils, but learning and experimenting is what makes the hobby fun. I'm looking forward to the next video on it!

[@timg5tm941]

Agree Mike! I’ll be looking at the coil itself in more detail soon

[@andy2E0JIU]

Hey Tim,your so easy to listen too.wish my maths teacher was like you when I was at school.looking forward to the experiment .

[@timg5tm941]

You are too kind mate 73

[@Tokyo1991.JL1AJE]

Tim, please excuse the double post but I felt this is worth posting as its own comment. Cheers, John. Word of caution. EFHW are high voltage at the feed point. Even just 10W with a 49:1 transformer will present 158V at the feed point. 50W will present 354V. So ideally the EFHW should have a high (tree/pole hoisted) feedpoint. If you run this antenna in a vertical configuration then you need to keep pets and children well away. Keep the great content coming!

[@timg5tm941]

Thank you John no worries. With the use of a capacitor within the transformer design, the naturally higher harmonic for 10m is lowered. Your point concerning the avoidance of return current is valid. I find that at 100w or less (portable power) that I just use a high impedance choke around 3m from the transformer and sometimes do not. Neither scenario has led to any rf issues. However, for best practice your point has great validity. Thank you very much for your comments. 73

[@spanners73]

Hi Tim, great video. I have a commercially built version of this "shorty forty" antenna, its made by HYendfed in the Netherlands. They market it as a 3 band Classic, I've used it portable when space is confined... the signal reports I receive are one to two S points down on 40m over a full length EFHW antenna.

[@timg5tm941]

Yes I have one too from them. A good compromise

[@Tokyo1991.JL1AJE]

This design as shown and if tuned for 14.175Mhz will tune the 10m band center (lowest SWR) at about 29.0~29.1MHz which is not ideal. Also you will need to choke the feed coax at about 2m from the matching transformer as EFHW are actually just extreme versions of an off center fed dipole. So you do indeed need the coax to work as a very short counterpoise. I’ve been working on a similar design that gives me a full 200KHz bw at 40m (hint: 35uH is not your friend), a full 350Khz at 20m and over 1MHz centered at 28.5MHz for the 10m band (SWR < 2:1 Max SWR at the dip less than 1.3:1). What’s more it’s field tunable with ease to allow you to plonk your minimum SWR dip in whichever portion of the band you prefer. Not yet able to record and post a narrated video so this comment will have to suffice. Word of caution. EFHW are high voltage at the feed point. Even just 10W with a 49:1 transformer will present 158V at the feed point. 50W will present 354V. So ideally the EFHW should have a high (tree/pole hoisted) feedpoint. If you run this antenna in a vertical configuration then you need to keep pets and children well away. Keep the great content coming! John

[@johnblake4503]

Hi Tim, I recently put up a vertical as an alternate to my 20m end fed inverted V antenna. It’s about a 10.5m of wire on a pole and fed via a 49:1 transformer. I’ve been able to raise the base of the pole about 3m so the top of the antenna is around 13m. It tunes great on 20m as a half wave and even better on 10m as a full wave, no radials. I’ve had some great DX on 10m despite a good proportion of the pole being in a tree. Another interesting fact is I’m able to get a tune via an internal tuner on 12 15 & 17, I’m not sure how efficient it is but I’ve had a couple of contacts to Japan on 10m and 15m ! It’s far superior on all bands mentioned than the inverted V for DX. I’ve also made an LC impedance match for 10m so thought I’d add this with another 5m of wire on the same pole to see how that compared. This vertical, probably due to being away from the house is mostly quieter. Work in progress, thought it worth mentioning as I seem of fluked getting on 15 😀 Great content as always Tim. John

[@timg5tm941]

Yes they CAN tune on those other bands. Efficiency isn’t great. BUT on a quiet band and with a good SFI anything is possible. 👍👍

[@TheArtofEngineering]

So it is an EFHW for 20 and 10 and loaded/trapped for 40m but deployed vertical? I had a similar antenna deployed horizontally, it worked ok … now have a EFHW inverted L for 80m up nice and high. This is a great option to avoid radials on the ground. Thanks for this. 73 de VK2AOE.

[@timg5tm941]

Yep it can work horizontally too for sure

[@RonanCantwell]

Great design, Tim. Looking forward to seeing how it performs in combat. How's about looking into a design for those of us that are less well endowed in the pole department.... (Fnarr fnarr!). My pole of choice is a 6m thing from decathlon. I normally use it to support the middle of an EFHW cut for 40m, but am wondering about some sort of vertical using the same pole....

[@timg5tm941]

Hi Ronan.. interesting, which band were you thinking about?

[@RonanCantwell]

@@timg5tm941 all the bands.... Although anything 40m and higher. I've tried a 40/30/20m vertical with switched loading coils (wound on toroids) but it was a bit of a dog to get tuned. Even then, a change in location knocked the tuning way out of spec. That's why I've stuck with the EFHW 'till now. Anything with a smaller footprint than the EFHW would be interesting.

[@timg5tm941]

@@RonanCantwell ok Ronan, certainly a 10/15m efhw with a trap for 10 would fit on a 6m pole. Either that or for 40 a base/centre loaded vertical (with ground radials). Maybe an off-centre fed dipole with a 4 or 9:1 unun for 10-17? With the unun having 4.5m above it and 1.5m of wire below? Need a tuner though. Just off top of my head.

[@RonanCantwell]

@@timg5tm941 interesting options. If you could have those built, tested, and on my desk by 16:30, that would be smashing 😉

[@timg5tm941]

@@RonanCantwell I’ll be trying at least one of them out and possibly modelling another!

[@dangermandave67]

Could you tune this to 30m by using a shorter upper length of wire and still have 10m and 20m?

[@timg5tm941]

I’ll check

[@doc145]

Hyendfed sells a 10/20/40 EFHW that has the exact dimensions as you show.

[@PC1I]

Not only Hyendfed... 😉 It is the standard outcome for a shortened 40/20/10 EFHW with 1:49 and a 35uH coil.

[@timg5tm941]

Indeee they do as I own one. The video I referred to in the early part of this one was of me using that same Hyendfed antenna. 73

[@timg5tm941]

Absolutely

[@adyg6ad73]

This one would be perfect for a quick an dirty setup. Any tips on the coil dimensions Tim?

[@Marcel-PG0M]

Take a 19mm PVC pipe and 80 turns of 0,75mm enammeld copper wire close to each other. . That's all. 73 !

[@timg5tm941]

I’ll be looking at that soon mate. In the meantime there’s lots online to guide

[@timg5tm941]

Exactly 👍👍

[@izzetmuroz]

Hi Tim ...

[@timg5tm941]

Hi there and 73!

[@johnnorth9355]

Far too 'conventional' Tim. I like building really whacky things (why use one balun when you can use two for instance ?). Not saying my designs work but I have fun trying.

[@timg5tm941]

Good stuff!