On Thu, 28 May 1998 09:17:03 +0000, Tom Rauch wrote:
>Oscillations sometimes do, but much more often don't, cause a snap,
>crackle or pop.
>
>How did you measure the S12 or S21?
>
The measurement was made with an IFR-1200S service monitor in Tracking
Generator Mode. Had a 10dB
pad on the cable going to the input of the assembly, but no attn on the cable
connected to the output connector
of the amp, I am going to redo the test with an attn there just for SP. The
connector of the amp was connected
to the Generator output of the TG, level about -20dBm. The input of the amp
had a 10dB pad on it then a cable
to the input of the SA/TG. The tune point of the amp was clearly visible on
the scope and running all the
controls moved and affected the isolation but the peak in feedback, so to
speak, was always the
combination tune point of the input and output, and never exceeded the -14dB.
The feedback then fell off in
both directions from this peak til it exceeded the range of the SA, about 85dB.
There was one other peak of
about -50dB around the second harmonic, near but not precisely, of the tuned
freq.
de Shawn
N7LQ (formerly WB7TDI)
The N7LQ station will be on from DN01fa for June VHF QSO '98
50-2304Mhz, 432 EME capable.....Hope to hear you on!!!!
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