jim bell <jdb10987@yahoo.com> writes:
There are some rather economical spectrum analyzers being sold today.
You have to be careful with those, the straight USB-dongle ones are going to be SDR-based, typically the RTL820T meant for DVB-T use (and re-purposed by half the hacking world for all manner of other things), then you have the USB- interface ones with more powerful SDRs, and finally you've got purpose-build spectrum analysers. Compared to the real thing, you're going to run into severely limited bandwidth (anything that spreads the signal across a wide spectrum is going to be difficult to impossible to deal with), and not-so- spectacular signal handling (there's a reason why the real thing costs thousands of dollars). That's not to say that they're no good, just that you need to be aware that you're getting what you pay for. If you've got a specific purpose in mind, check first that whatever you're getting will be able to do the job. There's quite a bit of material out there on this, google something like "sdr spectrum analyzer" to find articles on it. Peter.