1) Ruggedized. Can withstand rough handling and/or weather. Completely waterproof.

2) Cannot be switched on/off without a human doing it. Locking or recessed switches.

3) Lightweight.

4) Small.

5) Pre-packaged before an event, tuned up as one unit and pieces always kept together as a unit.

6) GPS antenna should be as high as possible and in the clear.

7) Amateur ant. as high as possible, and as high gain as possible.

8) Frequency-agile units (at least 144.39 and 145.79).

9) One battery pack supplies power for the entire package.

10) Low-power consumption.

11) Absolutely reliable as individual pieces and as an entire package.

12) True-DCD detect and unsquelched audio from the receiver, so that volume or squelch controls have no effect on the operation of the tracker.

13) External controls: ONLY a locking power switch and perhaps a battery state indicator. I expect that I'll keep everything on one frequency per event so don't need an external control for that. KISS principle.

14) Extremely flexible antenna that won't knock a searcher off balance even if on unstable footing (killing/wounding searchers is considered a no-no).

15) Field-replaceable battery pack.

16) GPS must have parallel receivers. Under tree cover the older sequencing receivers don't work well.

17) Prefer an amplified GPS antenna at the top of the package, or at least a bit clear of the searcher's body.

18) Entire package should be extremely easy and fast to mount to a searcher's backpack.

19) Callsign and important parameters should be labeled with weatherproof labels on the outside of the package, including the "If found, please return to..." label.

20) Cheap, readily available parts. Obviously the definition of cheap varies. My definition is really cheap.

21) Higher power transmitter if possible. 5W or better. Duty cycle is low, so can bump up the power a bit.

22) Self-contained. No wires hanging off of it. One rigid single-piece package.

23) Enough battery power for 8-10 hours per outing.


Small TNC's:

TigerTrak Site 1 or TigerTrak Site 2
MIM
Pic-Encoder
Kenwood TH-D7A
TinyTrak
AWT Tracker

Here are a couple of pictures of my latest ruggedized packaging attempt. The antenna is fake but is about 19" long. At the time these pictures were taken there was not equipment inside the tube. The tube is 2" ABS plastic. The top is an endcap. The bottom is a threaded end sleeve and a threaded cap. The idea behind this design is that it can be strapped on to the side or back of a SAR pack and stay out of the way. I plan on a 1/4 wave extremely flexible antenna going up, and a 1/4 wave ground lead going down through the housing, possibly hanging out the bottom of the housing if I shorten the whole thing. This'll give me a vertical 1/2 wave dipole. GPS antenna will probably sit on the top of the endcap. Picture 1, and picture 2.