First of all, low power broadcast band transmitters are sometimes avoided because they require tall towers. Actually, to get low angle vertically polarized signals, that's is what's required. What can a single tall omidirectional radiator produce? A certain local station in my area has a daytime output 5 kw and reduced power to a mere 8 watts at night. I live about 10 miles as crow flies from this station and I can pick it up clearly at night with an ordinary cheap radio. I can double the range with a good communications receiver and good antenna. Using this as a frame of reference I have something shoot for.Perhaps the easiest antenna to setup is a single random wire approximately 100-150 ft. long. The problem single end fed random wire is that it has anywhere from 500-1000 ohm or even more impedance and has to be matched to the transmitters 50 ohm output. The low cost MFJ-16010 does just that. It has 12 positions of switched tapped toroid and a variable capacitor. Several different combinations of inductor/capacitor settings gave me SWR readings under 2.0, the lowest I got 1.1 but my transmitter only putting out 6 watts. My transmitter connected to a dummy load was running 8 watts. My best setting with the tuner gave me a SWR of 1.3 but the transmitter was cranking a full 10 watts from a random wire! Not bad for a single banana jacked wire about 140 ft. long wrapped around my deck and to the nearest tree approximately 8-10 ft. off the ground.
A range check revealed a range of about 3 miles ground wave but I'm sure a horizontal wire provides plenty of skip at night. I'm more interested in local coverage and so antenna is going to get a boost in height. I'm thinking of using a small weather balloon to get the wire vertical. The tuner is basically part of the antenna and can be housed in a sealed Tupperware container at the base outside.
Another option is a helically wound tube or even a couple slinkys. Here the little MFJ tuner is actually used in reverse as the impedance is usually 5-10 ohms for these kinds of antennas. Well, the search continues for the perfect antenna.
