[Hammarlund] SP-600 HFO Alignment

[Al Parker]

Hi folks,
	I've done the whole job on over 2 dozen SP-600's, and hv just aligned 
some more.  You can see some of them at my website.
	I have never "sliced/knifed/tweaked/etc"  plates in the main tuning 
cap.  But the tracking has always come close.  It was never meant to be 
a freq. standard.  The idea was, and the military did so, was to record, 
in a paper log, the log dial reading at the frequencies you generally 
use, or at band edges perhaps.  This may require a calibrator or signal 
generator with known accuracy.
	I have always tuned the "455kc" IF's to the exact freq. of the xtal. 
This is accepted practice in all rcvrs with the xtal phasing method.
	As for drift (maybe off topic), after at most 30 min. of warmup, I've 
been able to listen to the MM Net on 14.300 for hours with only a rare 
tweak of the dial or BFO.
	The SP-600 is a great rcvr, let's keep them running.
73,
Al, W8UT
www.boatanchors.org
www.hammarlund.info

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole

On 3/24/2020 2:53 PM, Hy Chantz wrote:
> Hope all of you and yours are doing well during these challenging times.
> 
> Question if I might...let's say one has access to an xtal calibrator for their SP-600, and/or a WWV or other off-the-air reference.
> 
> Other than an out-of-cabinet tweaking, what - if anything - is the common "Vernier" to use, to get the SP-600 dial readout exactly "on"?
> 
> I don't readily see how one can easily align/move the dial scribe, there does not seem to be any commonly-installed  front-panel capacitor/trimmer to do this
> 
> Hy  W2HY
> 
> ----- Original Message -----
> From: "Bill Cromwell" <wrcromwell at gmail.com>
> 
> I took some radio/tv classes for a while (once upon a time) and they
> taught bending the *outer* rotor plates to get tracking in the AA5 AM
> broadcast band receivers. I have seen radios with intentionally bent
> plates and there was no satisfaction there. Don't do it.
> 
> On 3/24/20 11:11 AM, k2cby at optonline.net wrote:
>> I would repeat in boldface underlined Never bend the plates of the tuning
>> capacitor! It is undoable and a death sentence so far as proper alignment is
>> concerned.