Tag Archives: aprs

Digital Satellite Ops reference

It has not been recently that I have posted anything particularly relevant to ham radio. I don’t find as much time lately to play with the radios either.
I do however, try to follow several special-interest groups that have internet email distribution lists. Overnight I received an email item from VE6MVP, referencing a research project I have not heard of : Shadow-beacon. In particular, Tony was looking for additional reference on digital operations via satellite. The Shadow-beacon project intends to utilize the APRS infrastructure that is already in place and operational on the International Space Station (as well all over the planet surface via the Internet).

With this in mind I thought I would create a simple page, that provides linkage to several resources that I use on a regular basis. There are surely lots of additional pages that are just as relevant, perhaps you will post some of your favorites in the comment section below. Aside from having equipment setup to operate APRS digital, we need to know what satellites are available, and when and where to listen. Hopefully these links will help answer some questions you may have.
(Radio Amateur Satellite NA home)


Heavens-Above logoHeavens-Above
(live satellite/astronomy positions)H_coax

APRS from FindU

http://ariss.net/ (APRS via ISS : real-time) http://www.findu.com/cgi-bin/ariss/index.cgi  (basically same as the one above)
(APRS via Pcsat : real-time)H_coax

(ARISS status)H_coax
Orbitron - stoff.plOrbitron
(tracking software)H_coax

(UISS software)H_coax

http://www.dk3wn.info/p/ (Sat Blog) http://www.dk3wn.info/satellites.shtml
(Satellite info)H_coax

(multi-satellite status)


shadow-beacon homeShadow-beacon
(space plasma shadow’ experiment)H_coaxEnjoy  – -|||   |||- –

P.S. Please submit additional relevant links via the comment section below….


New DigiVOX interface by KH6TY

Having followed Skip’s trail of development in digital communications modes from Digipan into FLdigi, I was not at all surprised to learn of this latest kit.

kit, board & circuit

KH6TY Digi VOX kit available now

P.34 of the March 2011 QST details his latest soundcard interface. You may recall the VOX interface he presented in the June 2009 QST, well this is a step beyond as this version needs NO battery or power connection. Read more in QST or on Skip’s site ( http://sites.google.com/site/kh6tyinterface/ )

Get `em while they’re HOT . . .

Just buzzing around

During lunch yesterday, I was watching the local APRS scene via aprs.fi
– and watched a small plane as they took a leisurely tour over part of the county.

simple flight plan

Just looking around . . .

The track was tagged with tail number N56ML, and identified as KJ4RZR.
If anyone knows Mark, tell him to send me an email; I grabbed a few screen shots like this he might like to have. I didn’t see an email address for him on QRZ.com …………. Thought it looked pretty cool. Maybe he will offer to take me for a ride like that some day. He flew right over my house at one point.

Distributed telemetry collection

Tracking a long-duration high-altitude balloon is a different kinda problem.
For a typical ARHAB flight, we use standard APRS beacon packets on 144 MHz, which are collected from most anywhere and relayed to the APRS-IS database. A long-duration flight is often associated with a trans-oceanic attempt, and VHF APRS just won’t get it done. So, we turn to the HF digital modes and get help from multiple receivers scattered around the world. With enough volunteer listeners, someone’s location will have good conditions and can copy the position beacons. Thanks to a customized version of the FLdigi code (called dl-FLdigi) and a website called SpaceNear.US – there is now a new network for ingesting and processing this distributed telemetry collection.
(reference links at the end of this article)

spacenear.us map display

Flight path, and multiple receivers

This map shows a recent test flight, where WB8ELK used Domino EX16 encoding on his telemetry packets using a 200 mWatt transmitter on 7.077 MHz. His GPS receiver/HF transmitter/battery pack totaled about 1 pound. The balloon had a deliberately slow ascent rate, to keep it aloft for a longer flight. The launch was late in the day to avoid any solar heating. This balloon package travelled thru the dark of night, and landed in the middle of an artillery shooting range at Fort Stewart just west of Savannah GA. The map above shows the locations of the various operators that were listening for the beacon transmissions, using the dl-FLdigi program, and the path of the full flight.

Without going into a lot of detail here, I’ll provide some links, and encourage you to participate in these flights. This program makes it really easy.
The more listeners we have, the more likely we can track the entire flight.
There are plans for a trans-Atlantic attempt in Jan 2011.
Stay tuned for future details . . . . .

Links of relevance :
ARHAB = Amateur Radio High Altitude Balloons
APRS = Automatic Packet Reporting System
APRS-IS = APRS Information System (used a lot for vehicle tracking)
dl-FLdigi = customized program with special HAB mode (JamesCoxon)
fl-digi = linux/Windows program for soundcard modem communications
SpaceNear.US = tracking website
WB8ELK = a world-reknown pioneer in ARHAB sciences
WhiteStar = upcoming trans-Atlantic balloon attempt