I am new to HF. I'd like to put up an 80m delta loop. Due to aesthetic considerations I need to use coax to the shack. If tuned for 3.55MHz, I anticipate having a good SWR on 80m, 40m, and 20m. The transceiver is an Icom 7300 which tunes SWR 3:1 or less. Trying to avoid buying a tuner.
My question, essentially, is whether the feedline and balun choice can be optimized for not just one, but two bands — 80m and 40m.
— Bring down a length of 450 ohm line, then a balun, then coax? (What length, what balun?)
— Balun in the air at feedpoint (4:1?), then coax all the way?
— Something else?
I have read much about impedance, SWR, quarter wavelengths, and I simply do not have the background to make sense of it. Maybe one of you will make it click. Thanks.