Well thank you again if I use that method and use a bit less than 2m as a wire length I retrieve exactly the 35uH of the commercial ones.
What is still not super clear to me is how you would chose the length of the wire. It seems like in the range from 0 to lambda/4 , the required inductance varies from infinite to 0. So I guess we want the wire short enough to meet the dimension constraints, knowing that shortening the wire is enlarging the coil, and as a consequence, reducing the efficiency. Am I correct ?
From my experience with a 40/20/15/10 m version (20,x m wire) that is extended by a 110µH coil (plus some 1,6m wire) to allow also 80m is that the usable part of the 80m band is very minimal without a tuner. Maybe 50 kHz maximum. Then the SWR is too bad.
So if your tuner adds already enough inductance to also get 40m why mess around with the coil and 2 m extra wire. This will only make things more complicated to deploy and handle. Keep it simple … for SOTA. The chasers have the good antennas to pick you up
Yep. Built an 80/60/40/20 vertical on that principal: what coil do I need to add 2m up a 20m vertical to make it resonant on …
Presuming centre loaded is more effective than base loaded, which is what an ATU is effectively doing.
So I have a 20m 1/4 wave vertical on a sota pole with a coil 2m up: 1 coil, 3 taps and bypassed for 20m.
However, a better solution seems to be winding the coil on spaced former that lets you clip on to any turn in the coil so you can tune for the paricular operating conditions you find yourself in. Details on reflector(below)… yet to try it here.
Oh I see. So yes you are right, I will not bother with it and just keep it like this. I will do some more tests to check if I can tune on the other bands between 20 and 10m.
Because if I have to bring the tuner , maybe a random wire with a non resonant length would be a smarter choice. From the tables, it looks like 16m is an ideal length. It a bit too long for me but if can easily get 1.2 swr on all bands from 40 to 10m … I could consider the trade off.
Why aren’t u using the 20m? For a huge amount of summit’s 20m wire fits perfectly. And you are resonant on 40-20-15-12-10m without an tuner. For peaks with less space you could use a vertical antenna with coils.
Oh you mean the 20m wire long ? I though you were talking about the 20m band … Well, I dont use it because it is too long. For many summits I guess it could be fine but I think for the summits I’m aiming for, it’s impossible.
But I could give it a try and build a second one since I have like 30m of wire left …
Becoming 40m resonant without loadingcoils on a EndFed antenna and a short wire idk if it is even possbile. Maybe if u have a tuner that can tune a really high swr.
Of course monoband is not the problem. A lot of windings and the coil is ready
Check out this dipole: https://www.qsl.net/g3pto/shortant.html
Saw sometimes some random wire projects with an 4:1 or an 9:1 Balun. It seems that they are working with less wire length. But remember more wire radiates better
Yes, it’s about 8m footprint, which is suitable for most of the summits here.
The komunica is nice but kind of heavy for the genre (425g), especially compared to AX antennas, but it is multiband and very versatile from what I can see. There is 80m band and even 2m band !!! That’s incredible.
Yes very wide range.
I’m curious how its working on 80m. I can’t imagine that it works well on 80m…
But you can save some money and maybe build something like I do.
Yes I will wait for you report on this cheap solution. Anyway, I’m not planning to buy / build this type of antenna before a year or so, since it’s winter and the tricky summits are not very accessible at the moment.
