FreeScan: FM vs. WFM vs. NFM and BC346XT

[fmalloy]

In FreeScan, when I downloaded the freqs for Santa Clara County, CA, all the of freqs are set to "FM". I notice in the pulldowns it supports "FM", "WFM", and "NFM", among others. I am learning the difference between "WFM" and "NFM", but what does "FM" refer to?

I'm trying to understand the correct setting for my scanner...thanks for any help...

[cpuerror]

It sets how much deviation will take to bring the scanner to full volume level. For example, FM sets is to 15Khz which is pretty standard, and NFM is I believe 5Khz. So if you have a NFM transmitter, and the scanner is set to FM, it will sound quieter then it should be and vice versa.

[fmalloy]

Thanks cpuerror, but it's still not clear - you mentioned FM and NFM - what about the third, which is WFM?

I thought there was only WFM (wide) and NFM (narrow) - what is FM? The scanner and FreeScan support all three...

Also, all the Mode in the RR database seem to be "FM" - I don't see "NFM" anywhere, but most public service is supposed to use NFM. When I download into FS, it shows "FM". But when I dump from the scanner into FS, it shows "Auto". I am wondering if FM is really correct...

[cpuerror]

WFM is handy for monitoring things like drive throughs. since those 900Mhz headsets have a lot of deviation. The next step up from that is FMB, which is even wider and its used for listening to broadcast stations. NFM is about 5khz deviation, FM is 15Khz deviation. So having it set to NFM will make it a lot louder.

[qlajlu]

Originally Posted by fmalloy

I am learning the difference between "WFM" and "NFM", but what does "FM" refer to?

fmalloy, you will find an excellent discussion authored by Lou Maag in the RR Wiki about what these mean as they relate to the scanner community. Read clear through it.