Re: looking for a limited space multi band hf antenna to build
I operated a few times using a simple low cost Chinese fishing rod of approx 6 meters with a AWG 26 or so wire attached to it. You can extend the fishing rod as long as required, and i f you need more length to reach a quarter or half wave, simply hang the excess wire from the top vertically down. You can stick the fishing rod vertically up or horizontally from your balcony. They are super lightweight and low cost, so no concrete is required. A footage for a sun screen or so or a simple clamp to the balcony will serve fine. And, if they by accident fall off, no harm can be done by these lightweight structures and the antenna wire keeps it from falling all the way down. When ready, just pull the fishing rod in and store it
The only thing is that you need a ground, I used a clamp for holding things together when you are gluing wood etc. and did clamp the shield of the coax directly to the balcony. No bolts or whatsoever. Or use a stainless steel hose clamp.
When you make the wire 1/4 wave, it matches in most case quite well and no tuner is required.
I operated it on 80 with 9 meters of thin wire and used a simple air-coil and a variable capacitor as a parallel circuit to resonate the antenna when the antenna was connected at the top and the ground (coax shield an balcony) was connected at the bottom of the resonance circuit. A link of approx 4 turns was used to couple the circuit to the coax while inserting the ling more or less in order to match
It worked quite well for me and a few friends while living in an Hotel, very low cost