Getting your RTL frequency offset.

[jobdone]

Here is what I do to work out how far off frequency my RTL is. If you have access to an SSB transmitter and you know the frequency - use this. If not and you have some walkie talkies , then use these. Adjust your offset on your software until it matches the known frequency. I also have been known to use the raspberry PI (yes PIFM). Make sure your using the NBFM version of PIFM and try to use a known 'Legal' frequency. beware that the PI puts out some nasty harmonics without adding filtering. I have known 2 of my rtl's to be at 56ppm off and one at 32 (if I remember rightly).it is not advisable to try to tune up to a WBFM signal for obvious reasons.