[aprssig] PCSAT-3 opportunity?

'Scott Miller' scott at opentrac.org
Tue Jun 26 13:58:54 EDT 2007


How far do you want to take the smaller-is-better?  I can probably squeeze a
T2 into 1 cm^3, but it might take some flex cabling and thin boards.

I can squeeze a T2 into a 3x3 cm board easily enough.  Depending on the
space available it might be more desireable to go with a slightly larger
area and keep the parts on one side so that it can be mounted flush against
something else, though.

Do you need KISS support?  I'm assuming there's no need for waypoint output,
so that'll save a lot of code space for waypoint decode.  Throwing out the
Garmin binary code will also free up a huge chunk, plus a bunch of RAM, and
leave more space for encryption and a safe mode.

Get me whatever specs you can on the required connections and such, and I'll
start working on ideas.

The T2 won't do PSK31 RX, but it can beacon PSK31.  Any special digipeater
or telemetry options you'd want to see?

Scott
N1VG

> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Robert Bruninga
> Sent: Tuesday, June 26, 2007 9:55 AM
> To: 'TAPR APRS Mailing List'; 'Curt Mills, WE7U'
> Subject: RE: [aprssig] PCSAT-3 opportunity?
> 
> Plenty of time for the flight board.  A year maybe.  Just need
> to size the device.  Must be smallest possible to improve
> chances of a rid.  Two options:
> 
> 1) 145.825 RX/TX + TNC digipeater for APRS 
> 2) 28.120 MHz RX for PSK-31 + TX FM on 145.825
> 
> No GPS (not enough power avail).
> 
> Bob
> 
> > -----Original Message-----
> > From: aprssig-bounces at lists.tapr.org 
> > [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of 'Scott
> Miller'
> > Sent: Tuesday, June 26, 2007 12:41 PM
> > To: 'Curt Mills, WE7U'; 'TAPR APRS Mailing List'
> > Subject: RE: [aprssig] PCSAT-3 opportunity?
> > 
> > If you're talking about the one that fit in the original 
> > OpenTracker case
> > (with a hole in the board) then you're right, only a few of 
> > those were made,
> > though I've got a big stack of unused boards.  Trouble with 
> > those was that a
> > routing error in the oscillator circuit made them really 
> > flaky.  Those SMT
> > crystals are hard to mount properly anyway, and with the 
> > board error only
> > about 50% of the ones I built actually worked.  The T2-135 is 
> > mostly the
> > same circuit, but with a better layout, and has never had 
> > that problem.
> > 
> > The T2-135 would probably be usable itself, but the 
> > connectors aren't really
> > ideal.  If there's no rush, I can spin a new board rev in a 
> > couple of weeks.
> > I can get prototypes faster of course, but the cost climbs 
> > fast as lead
> > times decrease.
> > 
> > As I mentioned in the last email, I'm already working on a 
> > board that mates
> > with a commercial radio board, so it'll have all of the 
> > signals needed on a
> > 0.1" pin header.  Might not be the right levels for another 
> > radio, though.
> > Here's a picture of the radio in its housing, with RF board
> and TNC
> > installed:  http://n1vg.net/opentracker/images/dtx-plus.jpg
> > 
> > Scott
> > N1VG
> > 
> > > -----Original Message-----
> > > From: aprssig-bounces at lists.tapr.org 
> > > [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Curt,
> WE7U
> > > Sent: Tuesday, June 26, 2007 8:51 AM
> > > To: TAPR APRS Mailing List
> > > Subject: Re: [aprssig] PCSAT-3 opportunity?
> > > 
> > > On Tue, 26 Jun 2007, Jason Winningham wrote:
> > > 
> > > > Tracker2.  digipeater, remotely controllable/configurable.
> > > 
> > > I have one such in my hands, but I don't think very many of
> them
> > > were made.  Surface/mount Tracker2.  Tiny tiny tiny.  Maybe
> Scott
> > > has another one floating around, but I think there was a
> minor
> > > problem with the clock circuit on this board or with one of
> the
> > > components on the S/M version.
> > > 
> > > I don't know if he's planning to create any more of these
> right now.
> > > The T2-135 board may also qualify and is S/M too I think,
> but is
> > > probably somewhat bigger.  I know he's produced several of
> these.
> > > 
> > > It'd definitely be worth asking Scott.
> > > 
> > > --
> > > Curt, WE7U.   APRS Client Comparisons:
> http://www.eskimo.com/~archer
> > > "Lotto:    A tax on people who are bad at math." -- unknown
> > > "Windows:  Microsoft's tax on computer illiterates." -- WE7U
> > > "The world DOES revolve around me:  I picked the coordinate
> system!"
> > > 
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> > > 
> > > 
> > 
> > 
> > 
> > 
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