Spread Spectrum Radio 1

[sjmgd977]

I deal with spread spectrum radio systems in SCADA. I was wondering:
1) How you can select which frequency is best for a specific application?
2) Does the same path loss equation apply regardless of the frequency used?

Please advise if you have any experience in this area. Thanks in advance.

 

[VEBill]

The simple rule-of-thumb formula for path loss INCLUDES frequency as one of the input parameters.

Pathloss in dB = 32.45 + 20*log(f) + 20*log(d)

where
f = Frequency in MHz
d = distance in kilometers

Thing is, antenna gain (for a given physical size) can go up with frequency, and that's not taken into account by the path loss formula. This little detail certainly prevents the VLF bands from being overcrowded with folks seeking very low path loss... ;-)


The best frequency is a frequency that other people are not using. I'm not sure how that would jive with the particular SS system you're using. Also you antenna system matters.


PS: I don't know much about SCADA in particular. Stand by for others...