Yes, I had two HF antennas. A vertical with auto tuner right at the base. Auto tuners are pricey at 100 watt rating, and just downright expensive for higher power levels. A tuner is needed anytime your
antenna is not resonant for the operating frequency and does not match the impedance of your radio's output. You would be amazed how well your
radio can hear a signal and thus put out a signal when using a
antenna resonant for the frequency that you are operating. All a tuner does is fool your
radio into thinking the antenna load is both resonant and with a matching impedance.
So this is what I construct for that signal that the away stations report "are you sure your maritime mobile? Your signal is stronger than land based stations in your area". First, commit this to memory 468 / frequency / 2 = 1/4 wave length. The lowest frequency you will use is 75 meter
phone @ 3.9 mhz. 438/3.9/2= 60' antenna length. OK, now to antenna design, an inverted vee antenna with downward legs at 90* to each other will have an impedance of 50 ohms, just what your radio wants to see. The center is where you feed the two legs with coax and hoist up your
mast with a
halyard. Without traps, this would be a
single band (75 meter) antenna, but this is where you can have more resonant frequencies by adding traps along the length of those (2) 60' legs. A trap is a coil and capacitor that you design to pass all frequencies except the ones you will be using. You will make (2) traps for each band, 10 meters, 15, 20, and 40 meters. You don't need a trap for 75 meters because your entire antenna was cut for that band. The first trap towards the top, closest to you feed point is for 10 meters which would be for the voice part of the band at 28.6 mhz, so again 468/28.6/2X12= 98.1", and so forth for all the bands you want to operate. How this works is a frequency of 28 mhz sees the first trap as an open circuit, while a frequency of 3.9 mhz will see all the traps you installed as closed circuits, thus using the entire wire length. To get the correct angle between these two legs that you hoisted up your
mast, I use a company that makes 40'
fiberglass telescoping poles that when nested are only 12' long. These I attached on my old
Cal 40 on the bow and stern and just adjusted the angle they stuck out at to dial in my impedance. That is all it takes to have a resonant and impedance matched, multi band antenna that requires no tuner at all, and from my tests are 20~40 db better than a back stay. Back then, nobody made a solid state, high power HF amp, so I built my own. You sure don't need an amp, 100 watts from your radio will do a fine job, but when it comes to my signal, I go all out.
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