TRX-2: FM or NFM for P25 Trunked?

[Joseph11]

I've noticed when importing systems from the RR DB in EZ Scan, it appears as though anything P25 or DMR imports as NFM whereas most P25 conventional imports as FM. Has anyone compared FM vs NFM for P25 trunked systems? Which yielded a better result, specifically for systems that are simulcasted? Thanks.

 

[GTR8000]

There are a variety of emission designators used for various implementations of P25 (FDMA vs TDMA, subscribers vs infrastructure, Motorola LSM vs Harris H-DQPSK, etc.)

The commonality among them is that they all occupy a bandwidth of less than 11.25 kHz, and thus all P25 is inherently "narrow". This applies across the board, no matter whether it's conventional or trunked, FDMA or TDMA, single site or simulcast, VHF or 700 MHz.

All P25 is narrow, always.

 

[Nasby]

Some users have reported better results on P25 Simulcast with the "FM" setting (even though it is a WFM System).

You may want to try both settings to see which one gives you better results.

 

[Joseph11]

I experimented a bit with NFM vs FM on the local 700 MHz simulcast trunked systems and it appears in all situations NFM performs better than FM. A simple adjustment made monitoring a lot better (though simulcast distortion issues still persist).

 

[Anderegg]

I know the Uniden HP's are said to have improved reception of P25 when set to FM instead of NFM.

Paul