[amsat-bb] 2.4 GHz Helix & static type noise

["Geoff Taurins" <geofft@xxxxxxxxxxxxxx>]

G'day people. I am using a 2 1/4 turn helix feed on my 60cm dish feeding a
modified drake 2880 for 2.4 GHz rx. You can see pictures of at
http://www.geocities.com/vk3jdg When I dont have the noise problem the
system works very well. I am having problems with noise ( sounds like static
or at times a loose connection ) on rx. Sometimes the setup works fine,
sometimes usually within 10 seconds of switching the converter on I get
lots of noise on the rx and the S meter goes from S3 ( base line when the
converter is on and everything is working as it should ) up to over S9. The
amount of noise is dependant on the time of day ( night is generally less
than day time ). Now this doesnt happen all the time and if I spray the feed
with moisture ( only very small amount needed ) the problem disappears until
the water dries. We are having hot weather here and it is very dry. The feed
point on the connectors is sealed ( resealed / resolder numerous times -
with the same result ). I have rechecked / resoldered all the mods inside
the drake with no change. Is the problem static build up on the ungrounded
feed or something else ? Any ideas appreciated. I dont have any test
equipment for these frequencies so all tests are done with sats as the
signal source.

Cheers Geoff VK3JDG


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