[Premium-Rx] Synchronous Detector for WJ and Harris receivers

[Williams, Barry]

Jan and Craig,

 

Have you looked at the article in QST a few years ago?  It had a NE-604
to amplify the incoming carrier to limiting, this was fed to a VCO using
MV-109s and a NE-602, the VCO was sent back to the 604 to develop the
voltage to control the oscillator.  They also had a position to manually
control the VCO for product detection and had a 2nd 602 to take the
limited carrier and detect using it.  I have it in pdf format, but it is
real big.  If anyone is interested, has a fast connection and can
receive large files, I can send it to you.

 

Thanks,

Barry

 

________________________________

From: premium-rx-bounces at ml.skirrow.org
[mailto:premium-rx-bounces at ml.skirrow.org] On Behalf Of jan at skirrow.org
Sent: Wednesday, December 08, 2004 3:01 PM
To: Craig Anderson Ext 1365
Cc: premium-rx at ml.skirrow.org
Subject: Re: [Premium-Rx] Synchronous Detector for WJ and Harris
receivers

 

Hi Craig ....

I built a detector for my R390A radios that might do the trick. It is
probably more complicated than needed, but I'd tried a variety of
approaches and was not impressed with the stability or ease of use. My
design features a PLL stabilized xtal oscillator configured to allow a
toggle switch to select  USB or LSB. Another switch selects AM or SSB.
It requires an external audio amp.

As it is currently configured it requires a 455kHz IF input with a level
more or less what the R390A provides on the rear panel. It outputs an
audio signal that matches the R390A audio strip level. A trimmer on the
pcb allows this level to be adjusted so that there is no major level
change when switching between SSB and AM. The thing connects in place of
the diode load jumper on the rear terminal strip. For SSB it is in the
circuit, for AM it is bypassed so that the radio operates as it was
originally configured. It should be possible to adapt the thing for
other radios. It does not do anything about the AGC - this is a followup
project (for the R390A only) that I haven't gotten to. I also have a
second design built for the 500kHz IF found on some older Collins gear.
It hasn't progressed past the breadboard stage.

My detector uses an older Motorola MC1496 chip that has recently come
back into production. My intent was (and is) to make the detector
available as a bare board, or as a parts kit - but I've been
procrastinating at getting the final silk-screened pcbs produced. I'm
not in the biz of doing this kind of thing, but so much work has gone
into the prototypes that I thought I should share it! The real barrier
has been writing up some instructions, as assembly is definitely
required.

If you're interested I'd gladly share the circuit with you, or provide
more info on the kits. Please reply OFF LIST.

73s, Jan


At 12:21 PM 12/8/04, you wrote:



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I am looking for a good design for a 455KHz Synchronous Detector for my
WJ-8718 and Harris RF-590A.  I have seen several good articles in the
past but they all use chips like the MC13022 or Exar that are
discontinued and not readily available.  Rather than spend $600 bucks on
a SE-3 I would like to role my own.  Any ideas?
 
W9CLA
Craig L. Anderson, Ed.S.
Vice President - Administration
Saint Paul College
Minnesota State Colleges & Universities System
651-846-1365 Voice
651-846-1675 Fax
 
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