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+--- Thread: Rain effects: E.M.E... (/thread-477.html)
Rain effects: E.M.E... - VK2XV - 03-01-2018
Hi All,
Does anyone have any information about rain effects on Yagi arrays when used for E.M.E. on receive ?
During my 436 MHz observations of the Vela pulsar I notice when the antenna is wet there is a significant drop in received signal strength (during light rain the signal virtually disappears). The antenna is a long Yagi (5.7 m). I had thought that, while return loss is affected significantly, gain is less affected by water on the elements. I have done some preliminary tests by keeping the driven elements dry, but the effect still seems to be there. I ask for E.M.E. observations on this point as the loss of a few dB in sensitivity would be noticeable - just like my Vela pulsar observations.
Steve
Vela Pulsar observations...
RE: Rain effects: E.M.E... - VK2FAK - 12-01-2018
hi.
To get some response you might have better luck using the email reflector service...
http://mailman.pe1itr.com/mailman/listinfo/moon-net
John
RE: Rain effects: E.M.E... - VK2XV - 12-01-2018
(12-01-2018, 08:06 AM)VK2FAK Wrote: hi.
To get some response you might have better luck using the email reflector service...
http://mailman.pe1itr.com/mailman/listinfo/moon-net
John
Thanks John.
Good idea.
Steve
RE: Rain effects: E.M.E... - VK2KRR - 12-01-2018
Rain static QRM will obviously increase the SNR, you didn't mention if that was happening or not.
RE: Rain effects: E.M.E... - VK2XV - 12-01-2018
(12-01-2018, 10:40 AM)VK2KRR Wrote: Rain static QRM will obviously increase the SNR, you didn't mention if that was happening or not.
Hi Leigh,
As far as I can tell it is not rain static as it appears to persist after rain has stopped - but the antenna is still wet. The antenna is pointing almost straight up so all elements (both polarisations) are essentially horizontal such that water hangs onto them.
Steve
RE: Rain effects: E.M.E... - VK3PY - 12-01-2018
Steve,
Perhaps this might go some way towards answering your question:
http://www.qsl.net/yu1aw/Misc/wetantenas.pdf
I have not read it yet myself, but from a cursory glance it appears very interesting.
Cheers,
Chas
VK3PY
RE: Rain effects: E.M.E... - VK2XV - 13-01-2018
(12-01-2018, 06:41 PM)VK3PY Wrote: Steve,Hi Chas,
Perhaps this might go some way towards answering your question:
http://www.qsl.net/yu1aw/Misc/wetantenas.pdf
I have not read it yet myself, but from a cursory glance it appears very interesting.
Cheers,
Chas
VK3PY
Yes - that pretty much covers it.
Thanks !
Steve