Finally achieved good resonance on 20m for 80/20m loaded coil dipole!

I have been trying to optimise my 80/20m loaded coil inverted V dipole antenna for quite some time. Finally I have achieved an SWR of 1.2 on 14200 kHz, thanks to the guidance by SP3RNZ. In between I had trimmed a little more of the inner elements before the coil so that they were only about 422 cm. SP3RNZ suggested that extra length can be added like a stub hanging down from the junction of the 122 microhenry loading coils and the inner elements. Now the final length of the inner elements including the stubs will be 442 cm. Outer segments are currently 150 cm on each side.

This video clip shows the extra stub added for tuning one one side, hanging in a semi-circular fashion from the loading coil. As I do not have a NanoVNA, I am yet to figure out how to proceed further. The antenna still has ‘HI SWR’ on 80m band. It has SWR over 5 on 30m band, but somehow tunes with the automatic antenna tuner of my FT-710 radio, though it is supposed to tune only SWR up to 3. May be it has something to do with the coils there in the loaded coil dipole? Antenna has been mounted at a height of about 7m from the ground and the feedline is 15m RG213 cable. Excess length of cable has been kept as a small coil in the shack.

Here you can see that my CQ call with this antenna on 30m has been picked up by the Reverse Beacon Network skimmer at VU2PTT, 171 miles from here, with a signal to noise ratio of 18 dB. That means it is not just the antenna getting tuned on 30m, but the signals are also getting propagated. But I am not keen to work regularly on 30m band with high SWR in the feedline as it might cause some heating up of the resistors in the internal tuner of my radio. Tuned SWR is only the SWR presented to the radio and not that in the feedline and I have heard that extra power lost due to high SWR in feedline could be dissipated in the resistors of the antenna tuner!