[TenTec] Orion with 10m "buzz" (solved)

[Mike Hyder -N4NT-]

That's a puzzlement indeed !

73, Mike

----- Original Message ----- 
From: "Duane A Calvin" <ac5aa at juno.com>
To: <tentec at contesting.com>
Sent: Monday, June 28, 2004 11:45 AM
Subject: Re: [TenTec] Orion with 10m "buzz" (solved)


> Thanks Mike.  Actually, the tuner connection is not the problem.  If I
> pull the cable to the tuner from the "Y", the buzz continues.  It's being
> induced (or augmented) by just having the "Y" cable in the power line to
> the fan.  I plan to cut the cable apart to see how it's made after I
> replace it.  
> 
>         73,  Duane
> 
> 
> On Mon, 28 Jun 2004 10:45:12 -0400 "Mike Hyder  -N4NT-"
> <mike_n4nt at charter.net> writes:
> > Hi Duane--
> > 
> > You might want to add a little choke inside the tuner where the 12 V 
> > lead
> > enters, as well as a bypass cap if there isn't already one there.  
> > If the
> > fan is creating the buzz, then coupling it into the tuner may be the 
> > source
> > of your trouble and not the bad "Y" connector.
> > 
> > 73, Mike
> > 
> > ----- Original Message ----- 
> > From: "Duane A Calvin" <ac5aa at juno.com>
> > To: <tentec at contesting.com>
> > Sent: Monday, June 28, 2004 10:06 AM
> > Subject: [TenTec] Orion with 10m "buzz" (solved)
> > 
> > 
> > > I was disheartened last week to find a "buzzing" noise in my 
> > otherwise
> > > perfect Orion starting in the 10m SSB frequencies and continuing 
> > all the
> > > way up the band.  Both RX's, happens with antennas connected or
> > > disconnected or even deselected.  This weekend I started pulling 
> > cables
> > > to eliminate possible problem areas.  Imagine my surprise as I 
> > pulled the
> > > RCA plug out of the +13.8 V jack in the back and the buzz stopped! 
> >  What
> > > was it?  It appears to be a cheap "Y" cable that I used to power 
> > both the
> > > #310 cooling fan and the light in the 238B tuner.  If I plug just 
> > the fan
> > > without the "Y", no noise.  Same for the tuner.  If I plug just 
> > the fan
> > > through the Y cable, the noise returns, and is originating in the 
> > fan
> > > (noise follows the fan spin-up when power is applied, and stops
> > > immediately when the power is removed.)  I plan to build my own 
> > cable and
> > > will probably add some bypassing there that is effective at 28 
> > MHz.  Most
> > > likely no one else will see this problem, but I wanted to post 
> > this on
> > > the off-chance that they do.
> > >
> > >         73,  Duane
> > >
> > >
> > > Duane Calvin, AC5AA
> > > Austin, Texas