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Re: 2.4 GHz Helix & static type noise



That is kind of what I thought. Yes both of our units are modified. I m not sure
if the mod's are the same in both. I used all the G0MRF mods in mine.

Howie DeFelice wrote:

> It sort of sounds like the front end may be going into oscillation at a
> parasitic frequency. I suspect that when the feed is touched with moisture,
> it lowers the feed impedance and quenches the oscillation. Are both units
> modified?
>
> Just a guess....
> Howie
> AB2S
> ----- Original Message -----
> From: "Bill Hurlock" <bill@hurlock.net>
> To: "Geoff Taurins" <geofft@bigpond.net.au>
> Cc: <amsat-bb@AMSAT.Org>
> Sent: Tuesday, February 27, 2001 10:38 AM
> Subject: Re: [amsat-bb] 2.4 GHz Helix & static type noise
>
> > I have the exact same problem with mine and I use a Bar-B-Q grill dish on
> mine
> > which uses a dipole feed. My problem started a couple month's ago. It is
> winter
> > here and it is cold and very dry at times. problem is intermitant. Dipole
> is in
> > a plastic cover with a 1.5 foot pigtail going right into the Drake. Drake
> has
> > all the lastest modes in it.
> >
> > bill WA2TQI
> >
> > Geoff Taurins wrote:
> >
> > > 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
> > >
> > > ----
> > > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
> > --
> > Bill
> > WA2TQI
> >
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

--
Bill
WA2TQI


----
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