David, The question remains IMHO whether the data taken from short term "on-air" tests over distances which involve ionospheric propagation is useful in the first place.
Unless the vertical patterns of the A and B antennas are very similar in shape and lobe take off angle, it can be seen that changes in the angle of arrival of the test signal would introduce errors to the results of "on-air" tests. I have no experience with 160m, but on 40m for example the change in the angle of arrival of short path signals from the East Coast and Midwest can be large, and can change rapidly. Sometimes my dipole 70ft AGL which is end-on to the States, a "cloud`warmer" in that direction, will outperform a 40m beam pointed at the States - a disturbing result if taken to be the true performance of the beam. IMHO "on air " antenna tests need to be repeated many times over a fairly long period, preferably with the same stations. 73, Geoff GM4ESD David Cutter wrote on Sunday, August 29, 2010 6:36 AM >I would try a chart recorder in this arrangement; there's no mistaking >which > channel is which. Of course use a modern version using pc sound card then > you can squash up or expand the results for examination. > > David > G3UNA >> Alas, after years of doing A/B manual coax switch tests, I have given >> up on that exposing anything better than 10 db differences on anything >> other than stable local signals. And that is suspect because it is >> often ground wave, which bears no resemblance to sky wave. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
