Geoff I was in eQSO with L B Cebik some while ago on a similar tack; basically I asked how do we test a 4 square design made in EZNEC, say, with on air experience. He said more or less what you've just said, ie long term testing over wide azimuth and elevation. I had just designed a passive array for 80m with advantages over a 4 square. 73 David G3UNA
> 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
