Robert Green wrote:
"SMS" wrote in message
...
Robert Green wrote:

stuff snipped

Can I calculate the voltage drop just by observation? (Measure battery
voltage at one end and then through the run of wire to see how many
volts
remain and how much more than 12VDC I need to push through the wire to
get
12VDC at the front gate?)
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.

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.

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.