[ARDF] Re: Montreal fox controllers

Charles E. Scharlau cscharlau at earthlink.net
Sat Feb 18 15:53:49 PST 2006

Hey Jennifer,

I would like to second Dale's suggestion of using PTC thermistors instead of
fuses. I use them on all the batteries I'm using (mounted on their own perf
board as close to the battery terminal as practical), and have had no
problems with them. Another idea is to use a 100-ohm resistor in series with
the battery for the controller only. It limits the current should a short
circuit occur, but the voltage drop is insignificant at the normal current
that the controller draws. (I took this idea from Dale Hunt, actually.)

Also I'd second Jerry's suggestion of using PowerPole connectors. They are
the most reliable I've found... but they do take some practice to learn how
to install them without using the specialized (expensive) crimping tool. I
crimp carefully and then solder.

I like to use separate power switches on the power going to the transmitter
and to the controller. That way I can switch off all the transmitters,
switch on all the controllers and synchronize them, then turn on the
transmitters on-by-one as I place them in the field. For power switches I
use keyed switches (like you find on some computers), which have a low
profile and even if they get bumped they can't get turned on or off
accidentally. The keys I keep tethered to the ammo cans so that they can't
get lost.

Getting off the topic of reliable controllers: I would love to find
something better than ammo cans for holding and protecting the transmitters,
batteries, and controllers. Ammo cans are so heavy, and not particularly
easy to drill. They also look too military when carrying transmitters around
in public. But they are fairly cheap, readily available, tough, waterproof,
and naturally camouflaged. That's a tough combination to beat. To make them
more comfortable to transport I've placed insulating foam around the handles
(making them softer on the hands) and mounted a nylon strap to each one so
that they can be slung over the shoulder for easier carrying. It is still a
heavy load to lug around more than two at a time... but it is possible to
shoulder all five for short distances.

Charles NZ0I

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