I have a HP 141 series device which is reasonable from the point of view of
strong signal handling.
It is surprisingly easy to produce intermodulation effects at levels lower
than you would expect.
A "forest" of signals at -20 dBm will produce IM effects by the additive
effect of all their amplitudes.(you could easily get this from a 40M dipole
at night for example)
In fact, my friend Rod Green has done an article for QEX on a "figure of
merit" device to test receiver strong signal handling which consists of a
"comb generator" with harmonics every 20 KHz, and a bandpass filter covering
the band of interest - say 7.0 to 7.2 MHz. At a comb level of -20dBm most
receivers will be overwhelmed.

Richard

If I were designing a spectrum analyzer for the electronic instrument
market, I would shoot for at least meeting Hewlett-Packard Agilent
or Rhode&Schwarz specifications...R&D budget willing. That's a bit
steep for the hobbyist area.

The problem is that real incoming signals and the analyser's spurious
responses all look very much the same on the screen. When you can't
trust what the analyser says, it becomes very hard to understand what's
really going on.

Sigh. A spectrum analyzer, almost ALL of them, is one of the easier
instruments to characterize from the outside, using other instruments.
Frequency span, logarithmic linearity, passband of the final IF are all
relatively easy to determine from the outside.


Len Anderson
retired (from regular hours) electronic engineer person