[Collins] R-388 Y112

[Gerald]

On Sat, 2005-12-17 at 06:41 -0600, Stanley Adams wrote:
> Al Parker and myself were mulling over the options that are there when the
> main xtal filter (Y112) is nolo-worko.
> 
> Short of finding another 500kc 8 kc filter what is a fellow to do?
> KIWA option is out of the picture.  Does anyone know or suggest a cheaper
> avenue?  Murata Ceramic filters only work up to a CF of 456, so I do not
> think that this will be of any help.
> 
> Where are all the experts here?
> 
> Merry Christmas and Happy Holidays to everyone.
> 
> 
> Stanley Adams
> Memphis
> 
The crystal in the R-388 is NOT a bandpass filter. Its a single crystal
filter that acts more like a notch with an adjacent narrow pass band.
The radio's bandpass is determined by the IF transformers, not the
crystal. That notch is tuned and maximized with the crystal phasing
control. The receiver works very well with the crystal switched out.

There is a module that makes a 51J-3 (R-388) into a 51J-4 that holds up
to three mechanical bandpass filters. Its noticeable from the front
panel by a little lever sticking out from behind one of the other knobs
to the left of the main dial.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer