[aprssig] APRS Device in Mongolia?

Scott Miller scott at opentrac.org
Mon Apr 14 14:03:31 EDT 2008

How soon do you need it?  I've got a new project that might work:


5W transceiver with Tracker2 in one box.  It's got a solid state relay 
to control power to the radio board, shutting down for low-power sleep 
mode isn't a problem.  Keeping it under 10 mA would probably require 
swapping out the regulator for one with low quiescent current, not a 
difficult mod.

Battery voltage is provided, but there's no temperature sensor in the 
box.  Only the 1-wire bus is brought out to the connector, but for a 
one-off project it'd be easy enough to hard-code the device IDs of the 
temperature sensors and it can read a 1-wire quad ADC.  There are 
several 10-bit ADC channels on the MCU, but I don't think any of them 
are brought out to convenient pads.  Maybe one or two.

The VHF version should ship this summer.  Might have a few samples 
before then.


Robert Bruninga wrote:
> APRSSIG Group:
> APRS remote instrument in Mongolia?
> We might possibly have a ride to a mountain top in Mongolia for
> an automated stand-alone APRS environmental sensor.  If anyone
> wants to build one of these, maybe we might possibly get it
> added to the expedition.  Here is what I am thinking:
> 1) 5W TX on 145.825 APRS satellite uplink
> 2) Solar powered
> 3) very small, simple and lightweight
> 4) Possibly camouflaged
> Im thinking not a full WX station.  Too many parts and too
> bulky.  Just something that demonstrates our ability to report.
> Using the 5 channels of APRS telemetry from a KPC-3 or other
> APRS telemetry device, maybe these parameters:
> 1) Battery voltage      (2 resistors)
> 2) Solar luminosity     (photodiode
> 3) Air temperature      (Thermistor
> 4) Ground temperature   (thermistor
> 5) Ground Conductivity  (two stainless steel screws)
> This could tell us about the amount of sunshine, the moisture in
> the ground, the temperatures and the balance between all of the
> above..?
> The device would need to beacon once every 2 minutes 24/7/365.
> to be heard a few times a day by any of the APRS satellites.
> Hoppefully a ground station in Japan would feed it into the APRS
> system.
> At that rate, the average power is about say 10 mA at 8 volts
> and would need about a 1 watt solar panel (about 6" square)...
> I'd build it into a piece of PVC pipe that can be half buried,
> with the top section clear to allow the solar cells to work.  A
> whip antenna should hit the ISS or PCSAT..
> Anyone with time on their hands?
> Bob, Wb4APR
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