[Hammarlund] SP-600-JX-6

Mon Apr 24 22:13:40 EDT 2017

The story and history of ICM was a front page story in "The Oklahoman" newspaper for today.  It outlined how frequency synthesizers have virtually totally eliminated the market for individual crystals.  Those devices tend to use standard crystals that are now manufactured in huge quantities overseas.  The owner is 74 years old and he has decided now is the time to pull the plug.

Their engineer is a personal friend and a member of the ham club of which I am a member.

* * * * * * * * * * *
* 73 - Mac, K2GKK/5 *
* (Since 30 Nov 53) *
* Oklahoma City, OK *
* USAF, Ret'd 61-81 *
** FAA, Ret'd 94-10 *
* * * * * * * * * * *

________________________________
From: Hammarlund <hammarlund-bounces at mailman.qth.net> on behalf of Lee <L at w0vt.us>
Sent: Monday, April 24, 2017 20:23
To: hammarlund at mailman.qth.net
Subject: Re: [Hammarlund] SP-600-JX-6

Sorry, but International Crystals is now Out of Business.  They closed
there doors a few days ago never to return.

Lee, w0vt

On 4/24/2017 8:16 PM, Les Locklear wrote:
> ABOUT THE CRYSTALS
>
>  From Andy Moorer's website: http://www.jamminpower.com/main/sp600.html
James A. Moorer's Hammarlund Super-Pro SP-600 Page<http://www.jamminpower.com/main/sp600.html>
www.jamminpower.com
One of the most difficult parts of dealing with these old receivers is finding the appropriate manuals. Without schematics and other descriptions, it is a ...

>
> Scroll down to the bottom of the SP-600 notes and you'll find a handy calculator to use.
>
>
> I have had a number of questions about the crystals in the FCU (Frequency Control Unit) of the JX models. Getting a crystal is not a difficult process. International Crystals will be happy to sell you as many as you want, even in the antique HC-11 package, at about $15 each, custom-cut to your frequency. You do have to get the frequency right. It is not just the frequency of the station you are trying to receive. Here is a reduced version of the chart to figure out the crystal frequency, given the frequency of the desired station:
>
> To 7.4 MHz - add 0.455 MHz to get crystal frequency
> 7.4 MHz to 12.05 MHz - add 3.955 MHz
> 12.05 MHz to 44.05 MHz - Add 3.955 MHz and divide by 3 (3rd harmonic)
> 44.05 MHz to 54 MHz - Add 3.955 MHz and divide by 4 (4th harmonic)
>
>
> You will also have to specify some other stuff. Use the following:
>
> Case: HC-6/U
> Mode: PARALLEL
> Parallel capacitance: 40 pf
> Resistance at Resonance: 200-1000 ohms (not critical, as high as is reasonable)
> Mode: fundamental, 3rd or 4th harmonic from table above
> Precision: 25 ppm (you can get better by paying more)
> Signal Level: 2-5 volts.
>
> Les Locklear
>
> ----- Original Message -----
> From: <wb3fau55 at neo.rr.com>
> To: <hammarlund at mailman.qth.net>
> Sent: 4/24/2017 6:41:43 PM
> Subject: [Hammarlund] SP-600-JX-6
> ________________________________________________________________________________
>
> Folks, I got another question about the fixed freq operation.  As I can only guess,  how does one determine the freq of a crystal?  What I am asking is-  for a given freq,  below 7.4 mc,  do you add 455kc?  [or subtract?]  Then, above 7.4,  do you use 3.95 mc,  plus  or minus  the IF?  I know you folks know how to figure the xtal freq, for a given operating freq, so please enlighten me...tnx  Russ.
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