[Premium-Rx] WJ freq upconversion.

[Spencer Bahner]

The 8718 series receivers also had a 10.7 IF.

Spencer Bahner
Seattle

-----Original Message-----
From: premium-rx-bounces at ml.skirrow.org
[mailto:premium-rx-bounces at ml.skirrow.org]On Behalf Of refmon
Sent: Wednesday, July 30, 2003 1:33 AM
To: premium-rx at ml.skirrow.org
Subject: Re: [Premium-Rx] WJ freq upconversion.


Hi Scott,

Welcome to the bottomless pit!  As with all this species of equipment, there
are endless variations.  Watkins Johnson has used a number of IF's through
the years and models.

While I by no means am the leading authority, I can attest to IF's of
100KHz, 21.4 MHz, and 160MHz on the 8940 receiving system.  Higher IF is
associated with higher IF bandwidths...lower IF's with lower bandwidths.

The 8615 series receivers feature 21.4 and 160MHz.  21.4 is the more
processed, more general purpose IF.  The 8617/8 series use 21.4 MHz
exclusively with (and I'm on a limb here) one oddball custom unit that
developed 160MHz outputs.  It's probably fair to say that the 861x series
receivers are the more popular on the market and represent the typical gear
available.

I am not familiar with WJ's IF converters, although they do exist.  There is
a very flexible unit built by Apcom, which takes any IF in and outputs any
IF, and does all the intermediate combo's simultaneously.  I can trace that
if you are interested.  WJ also made IF-to-tape converters (and back again)
which enabled an IF signal to be recorded for later playback and analysis.
Apcom made them as well.

WJ's 21.4 wide-band output option (WBO) is generally distributed for use
with analyzers, demodulators, and direction finders.  This optional module
contains its own dedicated AGC system so that the option outputs -30dbm at
21.4MHz over the usable signal level range of the receiver.  This particular
aspect of the IF subsystems directly addresses your interest in the systemic
relationships among receiver product lines and accessories.

I can relate most directly to the WJ8971A-6 psuedo-doppler direction finder
system:  once the various receivers are equipped with the WBO option, the
receivers become interchangeable as front ends for the DF system.  That is,
all the receivers can be expected to provide common signal levels of common
bandwidths, thus enabling a single DF product to be configured into many
different systems.  Presumably, similar considerations apply to demods and
displays.

I'm sure others on the list can elaborate on demods in particular and
perhaps address the older receivers...say, pre 1975.

In the meanwhile, you can make a pretty fine upconverter with a mixer and a
test signal generator...maybe an amp and filter as well...

regards

John Collins
____________________________________________
----- Original Message -----
From: "Scott Schappert" <scottsch at ix.netcom.com>
To: <premium-rx at ml.skirrow.org>
Sent: Tuesday, July 29, 2003 11:32 PM
Subject: [Premium-Rx] WJ freq upconversion.


Hello to the group:



I am very interested to know if Watkins Johnson has produced upconversion
products:



Typical receiver IF (If correction is necessary, please notify me if not
typical): 21.40 MHz IF receiver output.



Required IF needs:



1.) 160.00 MHz



2.) 45.05 MHz



Does anyone have any background as to the sources of these IF outputs for
the following requirements:

1.)   SDU input @ 45.05 MHz

2.)   Demodulation input @ 160.00 MHz



In all truthfulness, I seek direction in my efforts to gain a greater
knowledge of the systemic relationship, with scant docs, of the peripheral
(e.g. SDU, demod) WJ systems and how they relate to HF / VHF / UHF family
receivers.



I will extend immense amounts of gratitude to all who may help me in my
efforts to understand this newfound fascination of these wonderful pieces of
hardware !



Regards, Slainte, and good health to all !



-Scott




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