[Hallicrafters] Tech Tip - SX-117 Chassis Ground

[Duane Fischer, W8DBF]

Thank you Roy for the update! I am adding it to that particular Tech Tip. 
Happy New Year OM!

Duane, W8DBF

----- Original Message ----- 
From: "Roy Morgan" <k1lky at earthlink.net>
To: "Duane Fischer, W8DBF" <dfischer at usol.com>
Cc: <hallicrafters at mailman.qth.net>
Sent: Friday, December 31, 2010 12:41 AM
Subject: Re: [Hallicrafters] Tech Tip - SX-117 Chassis Ground


>
> On Dec 30, 2010, at 9:38 PM, Duane Fischer, W8DBF wrote:
> (Quoting an old message from me):
>> One guy reports that his highly regarded TMC  GPR-90 suffered
>> mightily from oscillations and poor selectivity till he
>> soldered all the riveted ground tabs to the chassis.  I have
>> not yet done that to mine..
>>
>> Roy
>
> I later realized a puzzlement in that statement: the GPR-90 chassis is
> aluminum!  or at least is in one example I worked on.  I now have here
> a GPR-92A for alignment. Once it is running well enough, I'll see if
> it has the symptoms mentioned above, or another one:  a very strong
> signal, or the calibrator, will pull the BFO, so there is a kind of
> hole the beat signal falls into around zero beat.  A suspected cause
> for this is IF signal leaking over to the BFO and pulling it into
> synchronization when the frequencies are nearly the same.
>
> I appreciate the tip to monitor the diode load or detector output
> while bridging bypass caps and "shorting" ground lugs to the chassis.
> I'm going to try that one, too.
>
> Roy
>
>
> Roy Morgan
> k1lky at earthlink.net
> K1LKY Since 1958 - Keep 'em Glowing!
>
>
>
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