[aprssig] GPS to TNC APRS packet processor

[Andrew Rich]

Scott,

A while back I was playing with a PIC and I thought I would have a go at
making it do RTTY.

I was surprised at how well the thing actually worked.

I was expecting harmonics and all sorts of problems.

I used a Resistor ladder of 4 bits.

I hooked it up and the thing copied 100%

Ok so I started to introduce noise and the thing still copied 100%

It is amazing what these little chips can do.

Maybe one day we will have PIC based modems.

One chip - then we will have to work on modulation techniques.

Ok going to fire up my open tracker here and play with your new PSK code.

Cheers

-----------------------------------------
Andrew Rich
Amateur radio callsign VK4TEC
email: vk4tec at tech-software.net <mailto:vk4tec at tech-software.net>
web: http://www.tech-software.net
Brisbane AUSTRALIA



-----Original Message-----
From: aprssig-bounces at lists.tapr.org
[mailto:aprssig-bounces at lists.tapr.org]On Behalf Of Wes Johnston
Sent: Saturday, 18 March 2006 12:53 PM
To: TAPR APRS Mailing List
Subject: RE: [aprssig] GPS to TNC APRS packet processor


Scott, what is your guess for a price on the T2 kit?  I have a SCSG meeting
in the morning, and would like to "rough" them in when telling them about
it.
Wes

----- Original Message -----
From: scott at opentrac.org
To: 'TAPR APRS Mailing List' <aprssig at lists.tapr.org>
Sent: Fri, 17 Mar 2006 16:04:12 -0800
Subject: RE: [aprssig] GPS to TNC APRS packet processor


> > Just wondering if anyone has invented such a device, perhaps using a
> > microcontroller of some sort, that would sit in between a GPS and a
> > TNC so that TNC's which are not out-of-the-box stand alone tracker
>
> I don't think so, mostly because it costs just as much to make one that
does
> the same thing without needing a TNC.
>
> > and the TNC could take care of transmitting it.  Using a real TNC
> > would have its advantages versus a TinyTrak, et al on HF since the
> > method of carrier detection is by audio voltage.  On HF, I find it
>
> You can just add an XR2211-based carrier detect circuit to an OpenTracker
or
> TinyTrak.  The newest OpenTracker board I'm working on (the Tracker2) is
> already in beta testing and has a '2211 circuit built in.  It'll cost a
bit
> more than a regular OT kit, though.  And I haven't written the software
DCD
> code yet - white noise will trigger it right now.  That's a 5-minute fix,
> though - there's already a flag that tells it if the DPLL is synced, just
> need to feed that into the CD counter.
>
> I guess maybe using a T2 doesn't count as 'without a TNC', though.  It's a
> TNC in itself, and will do KISS and operate as a digipeater.
>
> Scott
> N1VG
>
>
>
>
> _______________________________________________
> aprssig mailing list
> aprssig at lists.tapr.org
> https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
>


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