In article ,
Doug Miller wrote:
In article . com, "Mark" wrote:
interesting question

is the wire a single insulated conductor or is it some kind of shielded
or multiconductor cable?

All the electronic dog fences I've ever seen use a single insulated conductor.

do you have acess to both ends and the break is in the middle of the
loop someplace?

Obviously he has access to both ends -- they're connected to the control unit.

i guess you could connect an AM signal gen to eac h end and follow it
with a portable AM radio

He already has an AM signal generator connected to each end -- the control
unit. All he needs is a radio, as I described in another post.

--
Regards,
Doug Miller (alphageek at milmac dot com)


The other day while jogging I passed an electrician truck,
with the guy there too retrieving some part -- and I
started a conversation.

I was asking about ground-rods, and how you could tell
if the cable going to them was perhaps open -- and
that led to discussing longer wires underground that
might have a break.

He said there was some kind of device they could attach
to *one* end and it could tell you how many feet down
the wire the break was.

He didn't know how it worked, he said.

My probably-incorrect guess is that it broadcasts some microwave
frequency down the wire, and vary the frequency transmitted
and see if you can get a resonance -- and do that for several
frequencies (relatively prime to each other? -- I make this
up as I type it in) and if there is some cheap computer
hooked to it, maybe it -- well -- tries to disambiguate
how long the resonating part is????

Something like a physicst or musician sending a continuous
tone in one end of eg an organ pipe that's got a blockage
somewhere, and by tuning the sound for a singing-in-the-shower
kind of resonance, dope out where the blockage is?

(Assumes that they're blind, or have no flashlights,
and no long pieces of wood to stick down until
it hits the blockage ... :-) )

Oh well, it was a try.


David