[AMRadio] FW: {Collins} Product detector for 75A-2 / 75A-3


Phil LaMarche plamarc1 at verizon.net
Mon May 18 09:16:18 EDT 2009


 
Here's the details.  Wasn't a problem to wire and it just plugs in the NBFM
socket.

Phil

Philip LaMarche 
LaMarche Enterprises, Inc.
www.instantgourmetspices.com

www.w9dvm.com 
800-395-7795 pin 02 
727-944-3226 
FAX 727-937-8834 
NASFT 30210 

K3  #1605

CCA 98  00827
W9DVM 



-----Original Message-----
From: collins-bounces at listserve.com [mailto:collins-bounces at listserve.com]
On Behalf Of Glen Zook
Sent: Tuesday, March 31, 2009 9:36 PM
To: collins at listserve.com
Subject: {Collins} Product detector for 75A-2 / 75A-3


Several people have asked if I would provide them with a built version of
the solid-state product detector for the Collins 75A-2 / 75A-3 receivers
which would plug into the NBFM socket.  Therefore, I have fabricated the
circuit into a sealed unit.  To use the product detector (which requires no
DC or AC voltage to operate) you have to change a jumper on the mode switch
and re-route the BFO signal to the NBFM adapter socket.  A marked up section
of the schematic is provided.

When the modifications are made, the product detector functions in both the
CW and NBFM positions of the mode switch.  When in the CW position the AVC
is turned off and when it the NBFM position the AVC is turned on.

The unit utilizes Schottky diodes and is isolated from any DC voltages that
are present on the NBFM switch.  Other than the 2 connections there are no
other changes required in the receiver.  Those modifications can be restored
with very little effort to remove the circuit and return the receiver to its
original condition.

Details of the product detector can be found at

http://k9sth.com/uploads/Product_Detector_ad-1.JPG

I am working on a "generic" version of the product detector that can be used
in many "boat anchor" receivers that will require hard wiring or some sort
of additional socket.

Glen, K9STH

Website:  http://k9sth.com


      
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