On Sun, 12 Jan 2020 14:36:27 +0000, Cursitor Doom
wrote:

I've got this weird problem with the network analyser I posted about
recently. The problem *seems* to be noise spikes on the DC voltage
control ramp which are causing spurious spikes in the frequency domain
on the RF output when viewed on an RF spectrum analyser.

In other words, it's picking up garbage from something in your shop
(or cave). I suggest you start by moving or removing all the
switching power supplies, wall warts, light dimmers, desk lamps, or
gizmos within a few feet that might have a switching power supply
inside. Next, cover the network analyzer with some aluminum foil to
see if the glitches are being delivered via RF. My desktop wi-fi
access point does that sometimes. If that also fails, drag your
network analyzer and scope to another part of your shop (or cave),
that's away from all the gizmos, and see if the problem persists. In
other words, determine if the garbage is internally generated,
externally radiated, or conducted via the power lines, clip leads,
cables, etc.

If you really want to see the noise, glitch, trash, garbage, or
whatever signal, set you scope so that the horizontal trigger is off
and the horizontal sweep is free running. Then, slooooooowly vary the
horizontal sweep until you see fairly stable glitches. If the noise
is periodic, you should be able to see something.


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