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[aprssig] TNC-X anyone?

scott at opentrac.org scott at opentrac.org
Sun Aug 27 18:09:00 UTC 2006

Lots of people are using the TNC-X.  For the DR-135 though, if you want to
hold off for a week or two, I may have some prototypes of my new Tracker2
board available - it's designed to be installed in the DR-135 in place of
the EJ41U TNC.  Assuming I didn't mess up anything on the board layout, I
should have working units next week.

As for decode performance, it's based on an NJM2211 demodulator, similar to
most TNC-2 clones.  In bench testing, I've had it decode about 94% of what a
KPC-3 or uTNT will decode from my test corpus.  I'll be doing some more
tuning to make sure it works well with the non-deemphasized audio it's
getting from the DR-135.  Interestingly, if I patch in my KPC-3's TCM3105 in
place of the '2211, I can decode about 2%-3% more packets than the KPC-3
itself.  Looks like my clock recovery code works better than theirs.

I've been running my Igate with a T2 prototype for a couple of weeks now and
it's doing fine.  The unit still responds to remote commands in KISS mode,
so I can shut it down or reconfigure it over the air even if my network
connection goes down.

And unlike the EJ41U, all configuration data is in nonvolatile flash, with a
retention time of at least 10 years.  And the firmware's easily upgradeable,
so bug fixes are no problem.

If the boards come out OK, I'll have several available cheap for beta
testing - mostly limited by how much time I've got to hand-solder a bunch of
little SMT boards.


> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Joel Maslak
> Sent: Sunday, August 27, 2006 7:09 AM
> To: TAPR APRS Mailing List
> Subject: [aprssig] TNC-X anyone?
> Is anyone using the TNC-X for APRS?  ( http://www.tnc-x.com/ )
> I'm looking at using it to replace my IGate's current TNC (the built- 
> in TNC in an Alinco DR-135), as I'd like to do proper KISS between  
> the computer and the TNC (I've managed to get the DR-135 to do KISS,  
> but sometimes it would kick itself out of KISS mode for no apparent  
> reason).  I'll probably keep using the DR-135 as the radio, while  
> using the external TNC for the packet encoding/decoding.
> Am I going to be happy with it in this application?  What would make  
> me happy is a TNC that decodes just as many packets as the Alinco  
> does, supports KISS (the flavor used by the Linux kernel drivers),  
> and requires very little "fiddling" once it's in place.  Transmit is  
> basically secondary to this - if it can send a packet the 
> local digis  
> can repeat, I'm happy.  I basically want this to be a "set and  
> forget" type of TNC as I am often away from home for several 
> weeks at  
> a time (yes, I check in on the IGate remotely, and can shut it down  
> remotely in case of problems).  I don't want something like the  
> Alinco which loses its' mind once in a while.
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