Radio Frequence scanners

[AndyL]

The tern "scanner" in RF analyzer conversations usually means a device that takes relatively large steps between samples. Using your mic receivers would be scanning since they only look at the specific frequencies you can tune the radio to. They ignore the bits between those frequencies. A real spectrum analyzer take a continuous sweep measurement, giving you much more detail.

 

Scanning and Spectrum Analysis are not the same thing at all really. Many radio mic receivers have a Scan function which just steps through the preset frequencies. Popular Scanner receivers beloved of Aircraft spotters, private eyes, reporters, etc. can usually scan in many different ways; banks of memories, particular ranges or bands of frequencies. As Mackerr says even when scanning a band or range of frequencies they have to move in discrete steps the size of which can be adjusted on many scanners. On some the size of the steps will be linked to the type of modulation that is selected, and even worse some make assumptions about what type of modulation is used in a particular band forcing the selection of modulation type and step size that is used.

 

When you use a radio mic receiver or something like WinRadio with a PC and WSM or wireless workbench and run it as a spectrum analyser (or analyzer) then that is what you get, albeit with what is known in spectrum analysers as a limited resolution. The resolution is determined in this case by the minimum tuning step size of the receiver that you use and the bandwidth of the filters in the receiver, which for a radio mic receiver is relatively wide. Most scanners for example will not reveal a (UK or European spec) digital TV transmission, it just looks /sounds like noise to them so they ignore it, a spectrum analyser, even one based on a radio mic receiver + PC or something like WinRadio will show it as an 8MHz wide block of noise rising out of the surrounding noise floor - unless of course the whole of the tuning range of your receiver is completely full of digital TV in which case you won't be able to see the nosie floor! Which is another reason why you do need an instrument that can see a wider range than just the frequencies that you can use.

 

:up: I'm really glad this topic has come up, I get so p'd off when people refer to spectrum analy(s)(z)ers as scanners, but normally just bite my tongue. And don't call a Spec. An. a 'scope' either.... ;)

[alex_kyuss]

Thank you Andy very helpful, I've found trying to learn adout RF rather not easy. So please anymore advise would be most welcome cheers.