{Collins} Checking crystals

Bob W5EUQ w5euq at VERIZON.NET
Sat Jul 14 11:46:29 EDT 2007

You are welcome Mr. Culpepper, fellow broadcaster. 

Re other comments received.
This testing is not meant to be for precision gear crystal testing.  I 
use it in choosing crystals, in determining quality, etc., for gear like 
Heathkits, Swans, Drakes, Collins, etc.  This test setup is typically 
good enough for this. 

For example, I took all of the crystals out of one of my KWM2A's and 
tested them.  I charted them and was very surprised in the results.  
Some were pretty weak but still worked.  Some were off frequency as 
indicated when bands were changed and the calibration dial had to be 
reset, not just a little, but a lot.  It helped give me some insight as 
to why the KWM2A worked the way it did on some bands.  

Another example is that some Heathkit crystals are a long way off, but 
still work.  When changing bands one may find the dial to be a long way 
off on some bands.  One can spend hours trying to "calibrate" one of 
these rigs only to become frustrated.

So I  charted the crystals here too.  Having some parts units to pick 
from, using this test method allowed me to choose crystals that would be 
closer to the frequency needed and/or may be stronger and better 
crystals.  Still maybe not "right on" in calibrations, but closer.

Nostalgia is setting in.  We used to take the old crystal apart and 
clean them.  When I was a novice in 1954, we even ground crystals to a 
different frequency.  Not too different, just a couple of 
kilocycles(oops... kilohertz), using substances like toothpaste to grind 
them. Being very careful to apply pressure evenly, going slow and using 
a uniform grinding pattern, like a circle or an 8.    It was fun. 

Now days, with the hermetically sealed crystals, we take what we get.  
Sometimes parallel capacitances can  be changed to "pull them on 
frequency".    A whole different subject. 

Bob  W5EUQ (old Broadcaster too, 50 years last December.  I started when 
I was two...hi)

William Culpepper wrote:
> Bob,
> Very good.  I enjoyed that.  Thanks for taking the time to put it in 
> print.
> William Culpepper
> W4BZ  (old broadcaster)
> __________

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