More on Nearly-Local 10M Vertical
From the 10M Mendocino/Lake/Northern Cal net last night I got a better idea of how a 10M vertical performed for nearly-local traffic (see prior blog.) Generally, it confirmed that the more direct (line of sight) the signal, the more important the polarization. In other words, there are fewer obstacles to skew the polarization.
For example, experimenting with polarization in QSO’s with Steve, KJ6EIF, who was also running vertical and line-of-sight (6 mi), the difference in signal strength for vertical vs. horizontal was 12-15 db. So, that’s closer to the 20 db cross-polarization figures I mentioned in the prior blog.
For more distant signals, like Wayne, W6WMV, who was over the ridge and down in the valley just south of Clear Lake (23 mi), and also on a vertical, the polarization difference was only 3-5 db. That’s still significant because it brought his signal up to being readable.
Oddly, I noticed no difference in signal strength of polarization with Dave, N0EDS, who is on the north side of Clear Lake (20 mi) and puts out a great signal here. One possible reason is that my antenna field was being distorted in that direction due to the metal roof of my house. (As mentioned earlier, the test antenna was not that far off the ground.)
One other thing to mention from last night’s net, Lee, N6MIV, over on the coast in Gualala had a terrific signal (40 mi and multiple ridges). He was using a 200 ft horizontal wire (G5RV), and he could hear my horizontal signal, but not so much the vertical. We didn’t get a chance to determine the signal difference. Maybe next time we can experiment more with that.
Well, hopefully sometime in the next month we can repeat the experiment with the test antenna a little higher off the ground. Where it is now is quite likely causing a distorted field, which will throw off the results.
I’d like to invite all Mendocino and Lake county hams (and anyone else who can hear us) to participate in our 10M HF net on 28.405 MHz at about 20:15 PT Wednesday nights.