I have been keeping my eyes open for a small cw-only radio to base a running-ascent kit on for when the wx warms up a bit. My KX2 would probably work, but the idea of it jiggling around in a running rucksack didn’t sit well. Anyway, today I scored an ATS-4, which was high on my list. Now to think about an antenna.
Many/most of our summits around here are tree covered. That means that for an ultralight setup I can usually leave my mast at home if I use some sort of end-fed antenna (let’s make the safe assumption that I am not going to want to try elevating the center of a dipole via tree limb). I am now examining the options which do not require a tuner. I’d rather leave that at home as well (especially since I’d don’t have a tiny one).
So one option is the trapped EFHW a la the one discussed this thread: End Fed 40, 20, 10m resonant antenna. That seems to be one good choice.
I also have this kit that I bought for another purpose:
My question for the group: could such an antenna be made “multi band” simply by attaching a radiator the length required for the lowest band to be used (40m for me) and then simply deploying the appropriate amount for the band in use? i.e. I’d put 61.5’ of wire on for 40m, but when I use it for 20m, I’d only deploy 28’ etc. Those lengths could be marked on the wire. I’d be using it for 40, 30, and 20m.
If it would work, one advantage I’d see over the trapped model might be flexibility in antenna size. If I get to the summit and realize I can only deploy 30’ of wire, I just work 20m etc. Not ideal, but I assume that kind of thing presents more of a challenge to the trapped model which assumes the whole wire will be deployed (from what I understand).
Thanks for any input!
Joe // N0MAP