[aprssig] Kenwood D700 Internal TNC Amazingly Mediocre!

spam8mybrain spam8mybrain at yahoo.com
Sat Aug 6 22:23:20 CDT 2016


I'm going to have to go along with Steve on this one. I've driven around with my Kenwood D710 and heard plenty of packets that couldn't be decoded by the Kenwood (alas, didn't have a laptop to run a software modem to compare). Also, someone I know who runs a digipeater/I-gate has compared using a TinyTrak 4 versus a SignaLink with AGWPE, and the software combo had a much higher decode ratio than the hardware TNC (and not all the missed packets sounded audibly distorted, although many did). 
Software TNCs just seem to be more effective at decoding lower-quality signals. Now, how many of those lower-quality signals could be fixed is another question; how many of those people just didn't know how to set up their stations (or don't care) versus stations with bad signal paths or hidden transmitter collisions, who knows.
But the poor quality signals are there. Are we going to be elitist and only accept those matching a particular ideal, or follow the Internet philosophy of "be conservative in what you generate, be liberal in what you accept"?
Andrew, KA2DDO 











-------- Original message --------
From: Steve Noskowicz via aprssig <aprssig at tapr.org> 
Date: 8/6/16  10:19 PM  (GMT-05:00) 
To: John Langner WB2OSZ <wb2osz at comcast.net>, TAPR APRS Mailing List <aprssig at tapr.org>, Robert Bruninga <bruninga at usna.edu> 
Subject: Re: [aprssig] Kenwood D700 Internal TNC Amazingly Mediocre! 


Hold on.  (I know Stephen is quite astute).  However, Keep in mind guys.  This test also depends on the signal transmitted from the digi.  Set up the digi differently and you can skew the data.  Perhaps the digi is setup wrong/differently....

-- 
 Regards, Steve Noskowicz
 Science & Technical Advisor
 http://www.challengerillinois.org/

--------------------------------------------
On Sat, 8/6/16, Robert Bruninga via aprssig <aprssig at tapr.org> wrote:

 Subject: Re: [aprssig] Kenwood D700 Internal TNC Amazingly Mediocre!
 To: "John Langner WB2OSZ" <wb2osz at comcast.net>, "TAPR APRS Mailing List" <aprssig at tapr.org>
 Date: Saturday, August 6, 2016, 3:18 PM
 
 Do the
 test again.  Set up a KWD to beacon at the fixed site once
 every 12 seconds on a separate frequency and then drive
 around with the three comparative modems.  My experience is
 the kenwood-to-kenwood performance is probably going to be
 best under weak signal conditions...  Bob
 On Sat, Aug 6, 2016 at 4:02
 PM, John Langner WB2OSZ via aprssig <aprssig at tapr.org>
 wrote:
 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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