[Tim Bently]

As part of a university course we are interested in monitoring and
identifying FHSS signals within the commercial broadcast frequency
spectrum. Please excuse a few questions.

In technical terms, how does a spectrum analyzer lock onto a signal
that constantly frequency hops?

Can this still be achieved if the frequency divisions and timing are
random?

What is the best type of spectrum analyzer for this purpose? Are any
special options needed?

Are there any technical guides available online that deal specifcally
with this type of application?

Once again, sorry for the several questions. I don't know how else to
ask.

Thank you for any advice.

Tim Bently

 

[Tim Bently]

Without knowing the target application, It is impossible to suggest a
unit without knowing frequency band, desired bandwidth, and noise
floor/sensitivity issues for the instrument.

Thank you for your informative reply. There is no particular band of
interest, as such.

The idea was simply to "sniff" around the radio and IF broadcast bands
and demonstrate objectively how it is utilized by FHSS.

IOW to find FHSS "hidden" information content and folllow it as it
shifts from carrier to carrier, noting the spread, time intervals,
etc.

If the modulating signal could also be demodulated/isolated, that
would be a plus. Now that I think of it, I am wondering to what extent
this is actually possible given privacy issues with telecoms.

Of course, it would be desirable to demonstrate this over as wide a
bandwidth as possible, but without making the exercise inordinately
difficult.

Any further suggestions along these lines would be much appreciated.

Tim Bently