[Hallicrafters] SX-111 Calibration?

[Richard Knoppow]

----- Original Message ----- 
From: "Bob Macklin" <macklinbob at msn.com>
To: "Halicrafters" <Hallicrafters at mailman.qth.net>
Sent: Friday, July 13, 2012 7:39 AM
Subject: [Hallicrafters] SX-111 Calibration?


>I received my SX-111 this week. The first problem was/is 
>the LO does not start reliably. I installed a new 6C4 and 
>that did not cure the problem. Then I cleaned the band 
>switch the best I could. It's better but not perfect.
>
> Now My calibration question.
>
> There is a knob on the front panel for "Dial Reset". There 
> is are no details in the manual about this control other 
> than to use it to adjust the dial.
>
> This control seems to be an inductor similar to the BFO 
> inductor in my SX-110.
>
> If I use this control to calibrate the dial on 80M the 
> dial is off on all other bands.
> There are no real instructions about precision tuning this 
> receiver.
>
> I am thinking about using this control with the crystal 
> calibrator to fine adjust all the LO coils at the low band 
> edge on all bands. I would do this with the "Dial Reset" 
> control centered.
>
> Is there any reason I should not do this.
>
> I could put my counter on the LO and adjust the band edge 
> that way if necessary.
>
> Bob Macklin
> K5MYJ
> Seattle, Wa.
> "Real Radios Glow In The Dark"

     There are handbooks for both the SX-111 and the Mk I 
version at BAMA.
     If the frequency calibration is way off its possible 
that its related to the intermittent starting of the LO. I 
would look for bad caps or drifted resistors around the LO. 
However, I would start by seeing if you can align the 
oscillator.  The calibrator will work but a signal generator 
may be better for aligning the RF because that should be 
done with a relatively weak signal.  The pointer adjuster 
should be needed only to correct small amounts of drift.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com