[aprssig] Ideal Tracker Spec (Cross country on 6 AA's)

Robert Bruninga bruninga at usna.edu
Thu Dec 6 18:37:16 EST 2012

Don't forget that you can run a micro-kind-of-tracker on 6 AA's for about
a month.  It only has to wake up for 1 second every 5 minutes and send a
single shortest status packet.  No GPS, no GPS power.  Can fit in a
cigarette pack.

Then use FINDU or APRS.FI to "vicinity track" you across country.  It
should plot a vicinity circle around the digipeaters you are hitting and
at least show the town you are in.

Lets see. 5W (RF) for one second every 5 minutes at 9 volts is 12 amp
seconds per hour for an average power of under 4 mA.  With AA's holding
about 2700 mAH, then that is about 700  hours or about a month.  Twice as
long if it only powers up in daylight.

Bob, Wb4APR

-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Matti Aarnio
Sent: Thursday, December 06, 2012 6:14 PM
To: TAPR APRS Mailing List
Subject: Re: [aprssig] Ideal Tracker Spec

On Wed, Dec 05, 2012 at 08:24:33AM -0800, Bryan Hoyer wrote:
> We are currently implementing a Tracker Function for our UDR56K
> radio with a USB GPS. (For more info on the radio
> Most trackers are implemented in small micros with limited
> resources whereas we have an 800MHz Arm (no floating point)
> running Linux 3.x kernel. The project will be open-sourced.


That UDR56K is by no means a limited resources thing - it is
both heavy and power hungry if you think about things like

A tracker in my opinnion is something you can put into your
pocket or back-pack, and run for days with a set of batteries.
Having it in a car pretty much removes the size, mass and energy

A tracker at a balloon is extremely mass and energy budged
optimized thing.

The UDR56K is a much more powerful thing, which is all fine for
running igates, and digis.  It is also really promising platform
to do new kinds of transmission protocols.

I would love to see about anything to replace that huge heap
of technical mistakes known as AX.25-over-Bell202-over-NBFM.

Advanced things like:
 * more efficient modulations (GMSK et.al.)
 * every packet/segment equiped with FEC covering all of
   the data (and not only partially like with D-STAR)
 * decoding to use soft-decission in FEC resolution
   (eats DSPs and FPGAs for breakfast, though)
 * CDMA-like multi-carrier operation for igates
 * Self-organized TDMA (alike AIS)
 * Receivers with legacy modulation support in parallel
   to other modes on all channels it receives.
 * Multiple central frequencies (channels) receiver
 * Multi-antenna receiver ( = diversity receiver)
   (Also multi-band if the front-end verter can't fold
    6m, 2m, 70cm and so on to single IF.)

What I do like is that the thing is split in two cards with
a connector in between.  Doing new radio parts will not need
replacing the host part.

> Bryan Hoyer K7UDR

73 de Matti, OH2MQK

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