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

[Mike Hyder -N4NT-]

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