On Fri, 14 Jun 2019 15:32:53 -0400, Ralph Mowery
wrote:

In article ,
says...

You haven't supplied any additional information on the equipment
you're using, duplex split frequency, and available test equipment.
The HP spectrum analyzer will survive the obvious overload, but I'm
not sure if it will produce usable measurements (without spurious
noise). As I mentioned, try reducing the input level with an
additional attenuator and see if the spurs disappear.

I have used a HP 8924C for a SA and sometimes it is difficult to tell if
it is overloaded at first even though it has the high power option and
will handle 100 watts.

I've had the same problem with every spectrum analyzer I've used. When
brand new, the SA is probably quite linear throughout its specified
dynamic range. However, after getting overloaded with too much RF
causing components to fry, the dynamic range can be reduced somewhat.
It's difficult to tell if something is broken, but the 10dB attenuator
test I previously mentioned is a clear indication that either
something is wrong or burnt out.

Notice that the marker shows a signal level of 4.52dB (upper right of
screen), but shows about +10dBm on the graticule.
https://i.postimg.cc/3JhhbHpC/IMG-3321-1.jpg
Kinda looks like the detector and/or the A/D converter that is
measuring the marker level has gone rather non-linear.

Sometimes to see the spurious RF you need to notch out the fundimental.

That works very well on UHF frequencies which have a 5MHz split
between transmit and receive. Unless you have a rather large cavity
handy, it works badly on VHF frequencies, where the split can be as
little as 0.6MHz. For the present situation, the SA shows a span of
almost 300MHz for a 161.4MHz center frequency. For all I know, the
spurious noise could be switching noise, AM/FM/SW/TV broadcasting,
other services, etc along with their intermod mixes. With a sweep
from 0 to 300MHz, that's about what I would expect with a cliplead
crammed into the antenna connector.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558