[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
by:
- 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:
https://github.com/wb2osz/direwolf/raw/master/doc/A-Better-APRS-Packet-Demod
ulator-Part-1-1200-baud.pdf
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
transmitting:
https://github.com/wb2osz/direwolf/raw/dev/doc/A-Closer-Look-at-the-WA8LMF-T
NC-Test-CD.pdf
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