[aprssig] 433 MHz operation
scott at opentrac.org
Wed Feb 15 12:40:23 CST 2012
Yes, when I said the OTUSB uses them transparently, I mean that they
behave exactly like they would for normal APRS, including KISS mode.
Buffering is still limited, but that will be changing - the OTUSB and T3
both have RAM available for a larger outgoing packet buffer, but the
code needs some major changes and a lot of testing to make sure it can
handle transmitting continuously while it still does everything else
The current prototype boards only have a USB mini-B connector and a
6-pin wafer connector for a GPS receiver, and no regular RS-232 serial
ports. The PA needs a 12v supply, so they still need an external power
source aside from USB.
On 2/15/2012 10:29 AM, Bradley Haney wrote:
> will we be able to possbile use these in a KISS mode?
> On Wed, Feb 15, 2012 at 12:12 PM, Scott Miller <scott at opentrac.org
> <mailto:scott at opentrac.org>> wrote:
> Hi all,
> I've been playing with some half-watt 70 cm data transceivers
> lately. I'm currently testing at 434 MHz, and with the standard
> crystal they should cover about 430 to 439 MHz. I'm not really
> familiar with the 70 cm band plan and figured I'd check here and see
> if people consider that a reasonable part of the band to be working in.
> I've got another small batch of them coming soon and might start
> selling a board based around it for people who want to experiment.
> Right now I'm using an OpenTracker USB variant. It's currently
> running at 4800 baud with some basic FEC - a (7,4) Hamming code with
> interleaving, not fancy but easy to implement. The transceivers
> will go up to 115200 bps. When I have time, I'll see if they can be
> made to inter-operate with G3RUH TNCs, but for now I'm going to
> assume that won't work.
> The really attractive part is that they're cheap - retail price
> should be not more than 1/3 what we're selling the half-watt
> transmit-only 2-meter modules from SRB for, and they're about the
> same size.
> There are still some bugs to be worked out, but the OpenTracker USB
> (and by extension the Tracker3) will presently work transparently
> with these radios, doing APRS at 4800 baud with error correction.
> I'll be working some more on them to improve mesh routing and
> channel access control to try to make them more suitable than
> vanilla APRS for short range, high rate tracking applications.
> aprssig mailing list
> aprssig at tapr.org <mailto:aprssig at tapr.org>
> aprssig mailing list
> aprssig at tapr.org
More information about the aprssig