Lunchtime project: loaded 10MHz vertical.

[UPDATED, COMPLETED VERSION OF THIS ANTENNA PROJECT DETAILED HERE.]

Well the sun is shining in Wales, but the wind is still a bit strong at 35mph gusts today.

I like the 30m band, but don't do enough operating there.  So I wanted to see if I could use a standard, nominally 7m fishing pole, to suspend a 5m long wire so that it would work as a 30m vertical with a loosely-calculated, detachable coil at the base, and as a 20m vertical without the coil.

10MHz bottom-loaded vertical, flapping in the wind...

Well, even though the coil was a bit of a guess, and I only have one radial for getting a rough idea if it would work at all, I already get a 1.25:1 match.  A standard 1/4 wave vertical has a native SWR of 1.3:1, so this is working well.

The coil itself is loosely wound on a 38mm diameter, ~170mm long PVC drain pipe section, 1.3mm enamelled copper of 13 turns.  Matching done using a SARK analyser and spreading/compressing the coil until best match achieved.

First test of the coil.  It worked!  Wire can later be taped or glued in place with silicone sealant, etc.

I'm currently sending 200mW WSPR, with very good early results, considerably better than anyone else I can find on the database in the UK on the 10m band running 200mW.  So this antenna can be made to a higher standard, have another 1/4 wave radial added, and deploy at the beach from the end of next week onwards, where travel to anywhere in Wales will be permitted.

 

My 200mW, vs. 5W from G0IDE.

 

Spots of 200mW, 16:26-17:26UT 16/03/2021.

Despite using 14dB more power than I am, my all-distances result is only 7dB weaker than G0IDE.

At DX distances, my 200mW is only 2dB down on 5W from G0IDE, though more data is needed.

Against what is probably a dipole (operators are extremely poor at corresponding or providing info about their antennas), my short 30m vertical is doing very well.