Hi Martin,
I think you've analyzed your situation pretty well when it comes to numbers of elements, beamwidths, etc. A few thoughts: - if you can try a few satellite passes from around your property with a handheld yagi, like an Arrow just gain a little first hand experience to see what your minimum elevations are going to look like. - you might be surprised to find that some houses are more "transparent" to VHF/UHF signals than others. There are several ops here who regularly work satellites with portable antennas from inside their houses. Don't consider every obstacle to be impenetrable.
With all that said, if I was in your position I'd go for a 3 or 4-element 2m yagi and I'd go to the extra trouble of getting crossed yagis so you can use circular polarization to reduce signal fading. For 70 cm the 7-elements on my Arrow handheld antenna has always been sufficient, and go for crossed yagis again. If you think the trees will really be a problem then go with 4 elements on 2m and a few extra on 70 cm, but realize that if you're buying commercial antennas you're stuck with what the sellers offer. This is about as much as I'd want to swing around with an inexpensive azimuth rotator (You didn't say what kind of rotator it was)
Finally, my antenna situation at home was even more awful than yours. My back yard was smaller than my living room and it was surrounded by 3-storey townhouses on all sides. I decided to become a rover and it was the most adventure-packed 2 years of my life! I travelled all over eastern VE3 and western VE2 and activated just over 70 grids, many of which had never been activated before. Amsat ops are always looking for new activations and are very grateful to thos who have the chance to get out there and activate them.
I hope this helps a little. You'll get plenty more replies and have lots to sort through soon!
73,
Ken Alexander (VE3HLS) So Phisai, Thailand Blog: bueng-ken.com
On Sun, Jun 16, 2019 at 2:44 PM Martin Cooper via AMSAT-BB < amsat-bb@amsat.org> wrote:
I'm contemplating building a couple of yagis, possibly even crossed ones, and putting them up at fixed elevation (i.e. az-only rotator). What I'm unclear about is how many elements to consider.
My location is really pretty dreadful for seeing sky. There's a big hill to the NE that restricts me to above 40 degrees in that direction. I'm in a single-storey house, with neighbouring two-storey houses to the NW, SW, and S. In between all that, there are other single-storey houses, and trees in most of the gaps between houses. I can't afford to put up a tower (and it could never get above the hill anyway), so I'm looking at not too much above my roofline.
To at least get through the trees, I'd think more elements would be better. But more elements narrows the beam, and at fixed elevation, that, at some point, will restrict even further how much of the sky I can play with.
I'm looking for thoughts on how many elements would be recommended, and how many would be too many, for a fixed elevation, both for VHF and UHF. Ultimately, I'd like to be able to get on the linears, so not limited to the FM sats. Any thoughts would be much appreciated.
Thanks in advance.
Martin. KD6YAM _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb