🚀 go-pugleaf

>From: gsk@idx.com
Date: Mon, 4 Feb 1991 15:05:58 GMT
Date-Received: Thu, 7 Feb 1991 01:45:43 GMT
Subject: HP Spectrum Analyzer Display Info needed.. HELP?
Organization: IDX Corporation, S. Burlington, VT
Newsgroups: sci.electronics

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- George Kaczowka   IDX Corp  Marlboro, MA  - gsk@ziggy.idx.com  -
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****  It must have been worse than that!... The model # was '851B'.

> My questions are:
>   What is the center of the IF expected for this unit, and would the unit
> itself serve as a panadaptor type display unit (spectral display about the IF
> center frequency) without additional equipment on a Shortwave radio with
> suitable IF frequency and bandwidth?

*After looking a bit closer..  Is the IF input at 20mhz?  I assume that I need
*to add a swept local osc. in synch with the display sweep, and mixer, etc...
*Am I on the right track?

There are three "frontend" modules for this display:  
8557  .01-350MHz,  8558 .1-1500MHz,  8559 .01-21 GHz.
They also fit the older 180-2 analog displays.  None of these are made
anymore.  Surplus prices vary, but 8558s and 8559s usually aren't cheap. 
Often in the $thousands range.  The 851 has a digital display.
There is also an old Network analyzer module (the 8755 scaler network analyzer)
that can be made to work with some modifications (change the sweep ramp from 
0-10V to -5-+5V).  It requires an external sweeper and the appropriate detectors
for the frequency range.

The IF is centered at 21.4 MHz, but the modules had detectors and video
filters in them. They output video to the display.  The spectrum analyzer
modules also had vertical and horzontal amps in them.  The display you have is 
only the power supply, and some digital hardware to digitize the video signal
and put it on the CRT.  I don't know what the 21.4 MHz input to the display 
was used for.  Essentually what you have is an X vs. Y oscilloscope with
a digital memory, but it is only designed to sweep left to right, one display
point per horizonatal point, and a modest maximum sweep speed.  

If you have some other specific questions I might be able to help.

Frank Ball   2LR-O             frankb@hpsad.hp.com
Hewlett Packard        
1212 Valley House Drive        (707) 794-4168 work
Rohnert Park CA 94928-4999     I'm the NRA.