[TenTec] RF Spectrum Analyzer

[Dr. Gerald N. Johnson, electrical engineer]

Some of the classic spectrum analyzers from HP, such as those using the
HP141 scope for display also include x y recorder outputs. Those are
fairly easy to interface to a PC for display. There was an article
suggesting that in a recent CSVHF or East Coast VHF Conference
proceedings (Available from ARRL, indexed at one of the SETI pages) for
when the scope tube dies.

In one of the UHF Compendia from Germany, there was a spectrum analyzer
that used a very modified TV set for display. Good from DC to 1 GHz or
better. One could use the PC to display its results with much less
effort than modifying the TV set. It included all the RF and IF
circuits. Though it would require working with discrete circuits, the
same concept could be accomplished with off the shelf mixers, maybe
filters, MMIC, and VCO from Minicircuits. There could be two operating
modes. A wide band mode where the VCO swept and the SA module detected,
and a narrow band mode where the VCO didn't sweep, but the sound board
based SA listening to a heterodyned (e.g. SSB detected) sample of the IF
did a narrow band analysis. The second mode, if it worked well might be
very handy for checking close in intermod products of transmitters,
while the wide band mode would allow checking for harmonics and odd
mixer products.

73, Jerry, K0CQ
-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.