Bob, et al:<div><br></div><div>What would you consider the simplest way to build such a system right now? Are there off the shelf components with which I could make a bunch of these simple APRS "beacons" - and do so inexpensively?</div>
<div><br></div><div>I have a series of small superpressure balloons that are ready to fly and just need appropriately sized payloads (mass < 100g). This would give me far more data than the 10 meter CW beacons that I currently plan to fly!</div>
<div><br></div><div>Thanks.</div><div><br></div><div>73,</div><div>Robert KC8UCH<br><br><div class="gmail_quote">On Thu, Dec 6, 2012 at 6:37 PM, Robert Bruninga <span dir="ltr"><<a href="mailto:bruninga@usna.edu" target="_blank">bruninga@usna.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Don't forget that you can run a micro-kind-of-tracker on 6 AA's for about<br>
a month. It only has to wake up for 1 second every 5 minutes and send a<br>
single shortest status packet. No GPS, no GPS power. Can fit in a<br>
cigarette pack.<br>
<br>
Then use FINDU or <a href="http://APRS.FI" target="_blank">APRS.FI</a> to "vicinity track" you across country. It<br>
should plot a vicinity circle around the digipeaters you are hitting and<br>
at least show the town you are in.<br>
<br>
Lets see. 5W (RF) for one second every 5 minutes at 9 volts is 12 amp<br>
seconds per hour for an average power of under 4 mA. With AA's holding<br>
about 2700 mAH, then that is about 700 hours or about a month. Twice as<br>
long if it only powers up in daylight.<br>
<br>
Bob, Wb4APR<br>
<br>
-----Original Message-----<br>
From: <a href="mailto:aprssig-bounces@tapr.org">aprssig-bounces@tapr.org</a> [mailto:<a href="mailto:aprssig-bounces@tapr.org">aprssig-bounces@tapr.org</a>] On Behalf<br>
Of Matti Aarnio<br>
Sent: Thursday, December 06, 2012 6:14 PM<br>
To: TAPR APRS Mailing List<br>
Subject: Re: [aprssig] Ideal Tracker Spec<br>
<br>
On Wed, Dec 05, 2012 at 08:24:33AM -0800, Bryan Hoyer wrote:<br>
><br>
> We are currently implementing a Tracker Function for our UDR56K<br>
> radio with a USB GPS. (For more info on the radio<br>
<a href="http://www.nwdigitalradio.com" target="_blank">www.nwdigitalradio.com</a>)<br>
><br>
> Most trackers are implemented in small micros with limited<br>
> resources whereas we have an 800MHz Arm (no floating point)<br>
> running Linux 3.x kernel. The project will be open-sourced.<br>
<br>
Hi,<br>
<br>
That UDR56K is by no means a limited resources thing - it is<br>
both heavy and power hungry if you think about things like<br>
balloons.<br>
<br>
A tracker in my opinnion is something you can put into your<br>
pocket or back-pack, and run for days with a set of batteries.<br>
Having it in a car pretty much removes the size, mass and energy<br>
constraints.<br>
<br>
A tracker at a balloon is extremely mass and energy budged<br>
optimized thing.<br>
<br>
The UDR56K is a much more powerful thing, which is all fine for<br>
running igates, and digis. It is also really promising platform<br>
to do new kinds of transmission protocols.<br>
<br>
I would love to see about anything to replace that huge heap<br>
of technical mistakes known as AX.25-over-Bell202-over-NBFM.<br>
<br>
Advanced things like:<br>
* more efficient modulations (GMSK <a href="http://et.al" target="_blank">et.al</a>.)<br>
* every packet/segment equiped with FEC covering all of<br>
the data (and not only partially like with D-STAR)<br>
* decoding to use soft-decission in FEC resolution<br>
(eats DSPs and FPGAs for breakfast, though)<br>
* CDMA-like multi-carrier operation for igates<br>
* Self-organized TDMA (alike AIS)<br>
* Receivers with legacy modulation support in parallel<br>
to other modes on all channels it receives.<br>
* Multiple central frequencies (channels) receiver<br>
* Multi-antenna receiver ( = diversity receiver)<br>
(Also multi-band if the front-end verter can't fold<br>
6m, 2m, 70cm and so on to single IF.)<br>
<br>
What I do like is that the thing is split in two cards with<br>
a connector in between. Doing new radio parts will not need<br>
replacing the host part.<br>
<br>
> Bryan Hoyer K7UDR<br>
<br>
73 de Matti, OH2MQK<br>
<br>
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</blockquote></div><br></div>