[aprssig] Kenwood D700 Internal TNC Amazingly Mediocre!

John Langner WB2OSZ wb2osz at comcast.net
Sat Aug 6 16:02:47 EDT 2016

The TM-D710 is a great radio, in many ways, but I also found the internal
TNC demodulator performance to be rather disappointing with real world
signals heard on the air.

The document below describes an experiment where a TM-D710 is used to listen
to APRS activity around my home.  We compare the number of packets received
- The internal TNC.
- KPC-3+ connected to D710 speaker out.
- A "soundcard TNC" connected to D710 speaker out.

The internal TNC decoded the lowest number.  You can read about the test
conditions here:


Any TNC can decode a good signal.  In the real world we find a lot signals
that are not so good.   Trying to extract something from them can be a real
challenge.  Take a look at some of garbage signals people have been


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