"SMS" wrote in message news:4a9660d3$0$1583
Robert Green wrote:

stuff snipped

Run 24VAC to the gate, and then use a 24VAC to 12VDC converter, i.e.
Google "SECUREMAX: AT12015".

Is it that long a run that I'll be losing significant amounts of power
using
DC? I already have a variable voltage switching power supply gizmo I
intend
to use for the project that uses one coaxial cable to send audio, video
and
power. It comes with a variable voltage power supply and an adapter on
each
end to inject and extract the audio and video from the cable.

Then that's different. I was assuming you were sending the power
separately. Generally it's better to regulate DC close to where you'll
be needing it because of the high I squared R losses. But if you can
jack up the voltage at the source then that's fine.

If there was a power savings payoff for going the AC route, I'd go for it,
but for a 50' run I doubt it would matter. I just need to be able to adjust
the output properly (it's a little slotted dial on the case of the power
supply) so I don't blow the camera's electronics. I guess I'll test it with
a 12V tailight bulb or load similar to the camera's draw before I plug in
the camera.

Good. I've read all sorts of disaster stories about frost heaving the
ground and unburying the wires in some electrical nightmare version of
the
movie Poltergeist. I just don't want to one day catch the lawnmower up
in
wires that have unburied themselves.

Yeah, that's why I enclose my sprinkler valve wirings in conduit or just
plain PVC. I had to put in some long runs of wire to valves in the back
yard.

Around here Comcast is legendary for "surface mounting" their cable by
laying cable right on the ground until one of their burial crews can get to
it. Sometimes they don't get to it before trauma occurs. I want to have
everything ready to do this all at once.

Conduit's going to add to the cost and complexity of the job, and I'd
like
to avoid it if burial grade cable is "good enough" to get the job done.

I think it would make the job easier. You don't need to use real conduit
for low voltage. Use plain schedule 40 PVC which is very cheap. You
don't even have to glue it with PVC cement. Use some short brass screws
on the couplings. Buy 20' lengths of PVC and you'll only need three of
them.

Actually, I have lots of left over central vac tubing that I think will make
very nice conduit and eliminate the need to store the excess. Good idea.
Thanks!

--
Bobby G.