[HBR] Ft-241's

[Hopperdhh at aol.com]

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.