[HBR] Ft-241's

[keith ford]

This large lot i have came through Kees in the big
crystal buy a year or so back.  About half or a little
better are good.  I've a crystal tester that came from
an estate sale.  I plan on testing them this weekend.

  I know i'll have more questions sunday evening.  

 Thanks keith.

--- Hopperdhh at aol.com wrote:

>  
> Keith,
>  
> Short answer, retune the IF.
>  
> First, I would build an oscillator and see if the
> crystals are still  good.  
> Time has a way of deteriorating these crystals.  The
> silver  plating tarnishes 
> (corrodes?) badly if they have been exposed to much 
> humidity.  I have quite 
> a few of these crystals that have gone inactive for 
> this reason.  Its 
> probably better to build a high frequency ladder
> filter  with more modern crystals.  
> If you are from a dry climate or the crystals  have
> been preserved well, maybe 
> you can pull it off.  Let us know.
>  
> I went through that exercise back in the 60's when
> my crystals were in good  
> shape -- grinding, etc.  I needed a carrier crystal
> to match that Collins  
> filter.  You know, 20 db down on the filter skirt. 
> Talk about  frustrating!  You 
> have to unsolder the little wires, edge grind the 
> crystals, solder them 
> back, try them out.  After about 10 passes like this
>  -- Oops, went too far.  Or, 
> uh-oh the thing lost all activity, won't  oscillate
> anymore.  Spent days just 
> ruining crystals.  Finally ordered  one from JAN!
>  
> Dan K9WEK
>  
> In a message dated 4/26/2006 10:23:55 P.M. Eastern
> Daylight Time,  
> kf4tap at yahoo.com writes:
> 
> In an  attemp to recreate a crystal filter,  i
> checked my stash of 142's for  channels46, 327, 328,
> 329.  I don't have these.  But i do have  them over
> and
> under like ch. 340,341 etc.  Those are about 15-16 
> kcs
> higher than the 455 IFT.  So di try to "pull the
> crystals or  retune the IFT?
> 
> Thanks  Keith.
> 
> 
> 
> 
> 
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