[Drake] Re: TR4-CW {Band to band alignment}

[Barry L. Ornitz]

Steve, K2FW, noted:

> I have a Drake TR4-CW/rit & when I change bands, the 
> calibrated freq changes at least 5kc or more.  In other 
> words, I have to re-calibrate in excess of 5 kc & on some 
> bands 15kc.  Is there anything I can do to correct this?   
> I've looked through the alignment directions in the manual, 
> but didn't see anything.

This is due to problems with the band-select crystals in the 
pre-mixing scheme.  The crystals originally supplied by Drake 
were fairly accurate and designed to work into the proper load 
capacitance.  Either your crystals have drifted, or (more 
likely) someone has replaced the crystals with less accurate 
ones or ones designed to work into a different load 
capacitance.

If you have a frequency counter, you can check for the proper 
frequency of each crystal and determine which ones are far 
enough off to replace.  There will always be some deviation, 
but typically it should be less than +/- 3 kHz.  I strongly 
suggest ordering new crystals from International Crystal or 
another reputable dealer.  

[I personally have never had a crystal made by JAN Crystals 
meet specifications.  Perhaps they are better today, but I 
quit ordering from them 20 years ago.  I have never had 
anything but perfect crystals from ICM.]  

International Crystal likely has the proper load capacitance 
information on file for your radio if you specify the model 
and serial number when ordering.

        73,  Dr. Barry L. Ornitz     WA4VZQ     ornitz@tricon.net