You don't know til you try . . .


Multi GPS Tracker Field Test

, posted: 15-Feb-2010 22:43

Made up a few units for the test.

This the smallest I can make using off the shelf parts.
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Used a nice case from Jaycar.
6 hr runtime on a 610mAh 1 Cell Lithium Polymer.
Could fit a slightly larger one in the case, maybe up to a 800mAh.
Loosing a little efficiency with the voltage regulator.



The field is not very 2.4ghz friendly with lots of trees.
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The modules have a advertised LOS(LineOfSight) range of 3000ft(900m)
cue tui's ad.
One does this with only 5mW(6dB), while the other uses 100mW(20bB).
In thick bush both tested to the same range, 40m.

http://www.moonblinkwifi.com/dbm_to_watt_conversion.cfm


The CCC (Control Command Centre) vehicle.
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1x network analyser, White one attached to radio antenna.
1x Receiver for the mapping laptop
2x laptops, mapping, network analyser.
3x Radios to contact the teams.

How well did they work?

GPS better than expected. Radios, poorer than expected.
The gps tracked well even when under tree cover and sideways.
I just dropped into a spare pouch of the player.

If the transmitter has to go through your body first then 5mw is not going to go far.

On this particular field the repeaters had a range of 100m.
The trackers 50m, due to poor placement on the player.

The plan was to shoulder mount the trackers for best gps reception and rf transmission.
Unfortunately I did not get a chance this time.
Next time.


For comparison some cell phone can pump out 2000mW(33dB)
http://en.wikipedia.org/wiki/DBm


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