Question: foliage, vhf
Bruce Draper
I put up my 6-mtr yagi antenna this morning, but now I’m thinking about moving it. It’s on a tripod on my roof, about 30 feet off the ground (good) but only 15 feet from and directly pointed into dense cottonwood trees (bad?). I don’t think it matters much on HF, but I’m guessing that it’s not great on 6 meters (and much worse on UHF). There are a couple other places on the flat roof where I could put it, but the best one is directly above the radio room and I bet there will be RFI problems on both RX and TX.
My question to you VHF experts: Is the absorption on 50 MHz by trees bad enough to make me want to move the antenna? -Bruce AA5B |
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Keith Morehouse
Look up document ITU-R P.833-9 for the actual numbers, but, IMO, it's really bad at 432, of some concern at 222 & 144 and not much of a worry at 50 MHz unless you're literally buried in foliage. BTW, below 100 MHz, it's considerable worse with vertical polarization then horizontal, but still negligible -W9RM Keith Morehouse via MotoG On Fri, May 3, 2019, 1:20 PM Bruce Draper <bruceaa5b@...> wrote: I put up my 6-mtr yagi antenna this morning, but now I’m thinking about moving it. It’s on a tripod on my roof, about 30 feet off the ground (good) but only 15 feet from and directly pointed into dense cottonwood trees (bad?). I don’t think it matters much on HF, but I’m guessing that it’s not great on 6 meters (and much worse on UHF). There are a couple other places on the flat roof where I could put it, but the best one is directly above the radio room and I bet there will be RFI problems on both RX and TX. |
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lewisre@...
I would suggest a series of tests with other 6 meter stations first. Also if possible you might compare performance with 10 and 2 meters. Dick, K5RHR, DM65uv On 2019-05-03 13:20, Bruce Draper wrote:
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Mike WB2FKO
Interesting to note that W7GJ has carved out a patch of Montana forest for his VHF aluminum: Lots of foliage there. On May 4, 2019, at 10:49 AM, lewisre@... wrote:
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K Chapman
Do a digi-mode with a S/N readout.
Then, compare with a known antenna with the directionality of the
yagi.
Kyle AK5Z
On 2019-05-05 04:25, Mike WB2FKO wrote:
-- Kyle Chapman Student, M.A. Übersetzungswissenschaft Universität Heidelberg Chapman Translation LLC http://kchapman.de (06221) 187 54 38 (Festnetz) +1 (505) 847-3071 |
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