[Lowfer] lowfer rec project

[Paul Daulton]

Andy mentioned in an email to me, all of his local reception reports have
 dried up. that got me thinking of a rec
project I have thought up. Back when I was playing with ATV I built or
 bought three stations for loaners when we 
put on a local repeater about 15 years ago just to have someone to talk to.
Lyle Kohler designed a rec to work with a software if, described on his
 home pages, with only a single NE602. the design I 
would use would be similar using two NE602(or NE612).
First stage would be a lowpass filter going into a self excited NE602 with
 a 5.185mhz microprocessor xtal, the second stage would
be a NE602 detector, also self excited with a 5.000mhz microprocessor
 xtal. I built a transmitter for ssb with the same scheme
with a USB filter between the two stages for psk transmission but only
 tested it as a bench model. For rec purposes I would leave out 
the filter and go DSB reception, a low level LM386 audio stage to drive
 the sound card for ARGO or Spectran would complete the receiver.      
 With Argo you wouldbe able to cover from 182.250 to 187.750( plus or
 minus 2750 khz). Calibration would be easy if you have a beacon or
 accuraterec and signal gen. Just locate the signal on Argo and plug in
 the offset.
I have built several qrp rigs of my own design and of late the Hendrickit
 KD1JV transceivers as described in Aug 2008 QST. I built one for 40
meters and modified the other for 80meters. These designs use NE602 mixer
 and NE602 product detectors and perform well..
What I am proposing could be built on a radioshack perfboard for about
 $15. With a cheap laptop and the ARGO software this would
make an ideal loaner a local friend, even a non ham, could set up and
 leave unattended for signal testing.
Any interest?
Paul Daulton K5wms
PS I havent looked at the catalogs, but if we can find a xtal pair with
 135 khz or 505 khz separation the same could be applied
to parta 5 and 600 meter reception.