[aprssig] Tracker power control relay

[Matt Werner]

>The TinyTrak3 has this capability already - I'm not sure what other
trackers
>might have implemented it.  I'm looking for input from anyone that's used
>this sort of setup before on how it might be done best.  I'm not really
>interested in controlling GPS power - I don't want to mess with the GPS
>start-up delay - just driving a small relay to turn on and off the radio.

I own one TT and set up another TT using the relays.  The TT feeds a small
reed relay which in turn activates the coil of a larger relay.  The relays
are both inside of a GE Delta radio (both setups are identical).  The PA of
the radio is always powered up but draws nothing until it receives a signal
from the exciter.  The rest of the radio is powered via the relay
(receiver, etc).  The GPS is powered seperately as is the TT.

I like the feature.  The only thing I don't like about TT's implementation
is the fact that it is designed to also power a GPS.  Thus if the GPS
looses it's lock for whatever reason it will leave the relay powered up
until the GPS relocks and a packet is sent.  Thus it can kill a car battery
if parked in the garage for a few days.  I like the fact that he allows you
to power the relay x seconds before transmitting - I think I have it set to
about 2 or 3 seconds or so - enough to get the radio turned on and ready
for business.

I've been considering picking up an OT for a while but didn't realize that
you didn't have support for the relay.  This would be a necessity to me in
my next application as well.

73 - Matt
KB0KQA