[Premium-Rx] Microtel PR-700B?

[w3jn]

5 kHZ -2000 MHz; has selectable upper/lower sideband.  Filters are 3 KHZ/10
KHZ/300 KHz/1 MHz if I recall correctly.  WIll do AM/FM/SSB/CW demod, has a
variable BFO or the USB/LSB positions are fixed.  WIll demodulate
subcarriers up to 150 KHz in AM/FM/SSB modes.

The built-in panadadapter has several modes:  you can view the baseband RF
spectrum when in subcarrier demod mode, regular scan which covers about 1
MHz of width, VAR SCAN which is variable and covers 0 to maybe half of the
band, and BAND SCAN which isplays the whole band.

Audio is headphone out only; it has a video output connector which is
positive video (to view video on an NTSC monitor you have to invert the
signal) and the video demod depends upon the main demod mode.  There is an
IF out of 21.4 MHz and various inputs/outputs for the panadapter scope.

This is a very, very good receiver.  It has some problems with front end
overloading and I'm not too impressed with the AGC in SSB.  Still, it does
EVERYTHING you'd ever want a receiver to do all in one relatively small
package.

The PR-700B differs from the PR-700A in that it has some extra signal
outputs as well as a rudimentary computer interface.  The computer
interface, IIRC, was designed to be used with the Commodore 64 and I've
never found any info on the protocols, etc., for its use.

If you find a good working one, it's a real pleasure.  If you have to fix
it, it is one of the most difficult radios I've ever worked on because of
its compact nature.  It is PACKED FULL of boards, rigid coax, modules, etc.
The scope is one of those Tektronix small scopes that has been repackaged
IIRC.

Trouble spots include the power supply (it's a switch mode PS that will take
110, 240, or 24 VDC).  If you accidentally switch it to the wrong voltage
you'll instantly destroy it, and the regulator chips are 4-legged TO-220s
that aren't made anymore.  Also, the HF preamp (that helps out in the 5
KHZ - 50 MHZ region) is a MOSFET design prone to burnout.  Finally, the pots
on the scope module are prone to failure.

Assume you're looking for one, or have one in mind?  Test it first if you
can and make sure that sensitivity is up to scratch.  It should have good
sensitivity on all bands with just a whip antenna.  Watch out for lots of
spurs showing on the panadapter - a few small ones are normal but lots of
big ones are not good.  Whatever you do DON'T hook it to a big outside
antenna and try to use the preamp.  The slightest static will fry it.

Hope this helps (?)

Best regards, John


----- Original Message -----
From: "Eugene Hertz" <ehertz at tcaf.org>
To: <premium-rx at ml.skirrow.org>
Sent: Thursday, August 05, 2004 10:55 AM
Subject: [Premium-Rx] Microtel PR-700B?


> Hi there. Any one know where I could find some information on a Model
PR-700B receiver by Microtel? Looking for basic info such as capabilities,
features, etc.
>
> thanks
> Eugene
>
>
>
>
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