14MHz Rhombic - a failure?

Full of enthusiasm from early experiments with a vertical rhombic, I set out with my shiny new yellow wire for 14MHz this morning.     

Rhombics are large antennas, and so I decided that I could not realistically deploy a wire more than 2 wavelengths long in the air.  This was partly due to controlling safety on a public beach (if you want to do the same thing, join EURAO and get their public liability insurance), and partly  because the wire has such a shallow angle at longer wire lengths that it ceases to function as a rhombic.

So, up went the 42 metres of wire, connections to earth made at each end, via a terminating resistor at the beaming end, which was pointing about 035 degrees.

Well, the results were pretty poor.  Whilst my 1W did get across to JA3APN, ZL2BCI and VK4CT when my vertical delta at home wasn't at all, comparisons with others in the UK, even taking longitude effects into account, showed that the rhombic was not very effective.  Taking into account the known enhancement available from the beach - typically 8-14dB - the rhombic was probably performing below that of the best UK wire WSPR antennas.

I did take along an RF meter this time,  which showed that the azimuthal pattern is very narrow - much narrower than models suggest, and only a few degrees wide.

Propagation conditions were tricky with this test, with enormous, presumably real short period variations, as the plot of SM2IAR's reception of my signal (this station was within the narrow beam of my antenna).  The geomagnetic field was extremely quiet (KP ~0), and had been for the preceding day:

14MHz reception of my 1W WSPR by SM2IAR.  TX frequency for the delta was lower than for the rhombic.

I won't bore you with a full analysis this time, because it's clear, even from a cursory look, that this antenna doesn't cut the mustard, at least at 14MHz and a 2-wavelength wire length.  It is a fairly easy antenna to put up, taking no more than a couple of minutes.  But that time is far better spent on putting up an even easier-to-erect 1/4 wave elevated vertical, which we already know will beat the socks off everybody else from the beach.

There was, though, a reasonable result - but almost certainly no better than a 1/4 wave vertical would have achieved - in my signal to OH3FR:

14MHz 1W WSPR received at OH3FR

I still think it's an antenna worth testing again at higher HF, because of the multiple wavelengths that then come into play with this same kind of wire length.  But that will have to wait for another day...