[Amps] rx noise?

[Joe Subich, W4TV]

Check the bias switch (relay, transistor, ?).  If cutoff is 
not being applied in receive, the tube will generate wideband 
noise ("shot" noise). 

73, 

   ... Joe, W4TV 
 

> -----Original Message-----
> From: amps-bounces at contesting.com 
> [mailto:amps-bounces at contesting.com] On Behalf Of Paul Kraemer
> Sent: Saturday, December 06, 2008 12:57 PM
> To: n8de at thepoint.net; K1TTT
> Cc: Amps
> Subject: Re: [Amps] rx noise?
> 
> 
> How about from a zener diode in a bias supply.
> They make dandy noise generators and were the source of 
> widband rf for the 
> old Omega noise bridge. The current to make noise is 
> critical, line voltage 
> upset could put it at that point?
> Just fuel for thought.
> Paul K0UYA
> ----- Original Message ----- 
> From: <n8de at thepoint.net>
> To: "K1TTT" <K1TTT at ARRL.NET>
> Cc: "Amps" <amps at contesting.com>
> Sent: Saturday, December 06, 2008 11:24 AM
> Subject: Re: [Amps] rx noise?
> 
> 
> > Dave,
> > Sounds like a leaky power supply capacitor.  Might be a cold solder 
> > joint in the capacitor chain. Good luck
> > Don
> > N8DE
> >
> > Quoting K1TTT <K1TTT at ARRL.NET>:
> >
> >> I have a commander hf-2500 (pair of 3cx800a7's, no qsk) 
> that seems to 
> >> be working fine.  However, during cqww cw last week I had 
> to pull it 
> >> off the 20m station because it was making a broadband 
> noise while on 
> >> receive.  I put it back on the station today and it isn't doing it 
> >> now.  I tried warming it
> >> up a bit and it still didn't do it....though its obviously 
> not as warmed
> >> through as after 40 or so hours of cqww.  The only other 
> thing I noticed 
> >> is
> >> when it was doing it the plate voltage dropped a bit, 
> maybe 50-100v, but 
> >> I'm
> >> not sure if that was a cause or effect since the line 
> voltage sag from 
> >> the
> >> other stations can make the hv sag a bit here.  Any ideas 
> where to start
> >> looking??
> >>
> >>
> >> David Robbins K1TTT
> >> e-mail: mailto:k1ttt at arrl.net
> >> web: http://www.k1ttt.net
> >> AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
> >>
> >>
> >>
> >>
> >> _______________________________________________
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> >>
> >
> >
> >
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