Doublet Troubleshooting

[VA3KOT John]

OK, thanks for the suggestions. I was transmitting on low power in LSB, the radio said I had an SWR 2-3:1, but the needles on the tuner were barely moving. I guess indicating a super high SWR. I roughly measured my feed line and it’s about 55’, in the danger zone I guess. The experts suggests 80’ is a safe length. I’ll add 25’ loosely coiled in the house and see what that does, and tune on CW. The ladder line does cross a drain pipe perpendicularly, about 3”, also the dipole (65’ on both sides of the feedpoint) brush against some branches, the wire is insulated.

Doug, my MFJ-949E tuner has a 300W/30W switch; maybe your tuner has the same. If you are operating low power try the 30W setting then the needles will move further. The meter only indicates a high SWR when the needle on the "Reflected" side has a high reading. If the needles don't move very much at all it only means the tuner isn't seeing enough power from the radio. Again, see if your tuner has a low power setting. And don't try to measure SWR in LSB mode, use CW.

Don't worry about the antenna wires touching branches; it doesn't matter at HF as long as the wire is insulated, as you say. I don't recommend coiling the excess ladder line. You can do that with coax because the coax braid is grounded. Ladder line has a voltage on both conductors so you may get unpredictable interactions if you coil it. Better to route it round some trees or poles outside. Also, don't let the ladder line touch the ground.