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[aprssig] APRS remote WX opportunity

Thomas Krahn thomas at tkrahn.com
Wed Apr 18 20:49:08 UTC 2012


Bob,

I've written some Arduino code  that basically changes the APRS TX 
frequency when the ISS is in view.
http://code.google.com/p/trackuinoiss/source/browse/#svn%2Ftrunk
However I still use a lookup table to identify the position of the ISS.

Essentially you will want to transmit only when the ISS is close, but 
then more often.
In Mongolia probably no-one would care if you transmit every minute 
while the ISS is over head.
The rest of the time you could save energy (or change qrg to 30m?)

Bruce G. Robertson VE9QRP has written a nice library (qrptracker for 
Arduino, check "Modeswitcher").
Unlike me he uses the Keplerian elements instead of a lookup table. but 
I haven't been able to merge the code yet.

Biggest problem will be to update the Keps out there in the Mongolian 
desert. Maybe we could find a way to do this through APRS messaging?

Or you could simply transmit only after you received a beacon from the ISS?

Just random thoughts.

Thomas
KT5TK/DL4MDW


On 04/18/2012 03:24 PM, Lynn W. Deffenbaugh (Mr) wrote:
> A 30m station for your ground-based excursion would have a better 
> chance of being received.  The same is probably even true for the 
> solar weather stations, which, BTW, I'd have set to every 5 minutes 
> because at 10 minutes you'd stand a pretty good chance of missing 
> entire the shorter ISS traversals.
>
> Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32
>
> PS.  I'm still looking for a good, cheap, lightweight, 30m APRS 
> tracking system for back-country packing use.  It'd be a bonus if it 
> could handle reception as well enabling APRS messaging when the 
> conditions are right.
>
> On 4/18/2012 4:21 PM, Bob Bruninga wrote:
>> Anyone want to put their APRS or Satellite talents on the air in 
>> Mongolia?
>>
>> A Scientist goes there each summer and has the opportunity to put 
>> some small
>> solar powered APRS weather trackers on the air (via the ISS).  Here 
>> is his
>> idea:
>>
>> If anyone... would like to hack together 2  or 3 small solar powered 
>> APRS
>> transmitters and 2 meter antennas that are attached to a very small 
>> weather
>> station (ONLY humidity, pressure, temperature, sunlight) we can leave 
>> them
>> on mountain tops in the GOBI of Mongolia this summer.
>> The transmitter and solar panel (with some lithium re-charge batts.)  
>> can be
>> set to squirt data every 5 or 10 minutes.  Basically, the signal will go
>> straight up, and this will hit the ARISS space station APRS repeater 
>> about 4
>> times per day.  If there is a receiving gateway APRS-internet station in
>> Russia, China, or Japan under the footprint of the repeater, then we 
>> can get
>> data on weather in the Gobi for a year or maybe more depending on the
>> robustness of the transmitter, batt, solar panel.  What do you think? 
>> These
>> would be non-recoverable items.  Just a thought that may interest 
>> people.
>> This would be a normal HAM "no budget operation" and it has to be very
>> small.
>>
>> Probably not enough time this year, so I can set up a test system 
>> this year
>> on our Landcruiser there with my Kenwood HT and we can see if we can 
>> repeat
>> data into the Internet with 5 watts and with APRS from the Gobi while 
>> I am
>> there.  Fun stuff - I think.
>>
>>   I would love to set up remote weather stations like that deposited 
>> in areas
>> where we did our work to get env. data that way, that would be so cool,
>> until a wild Camelus bactrianus ate one... then maybe we could get
>> gastro-physiol. data on one of them.....
>> --------------
>>
>>
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>
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