Michael Black wrote on 7/26/2017 5:16 PM:
On Wed, 26 Jul 2017, Ian Jackson wrote:

In message , Gareth's Downstairs Computer
writes
On 26/07/2017 16:33, Jim H wrote:
On Tue, 25 Jul 2017 13:58:27 -0500, in ,
Bob Wilson wrote:

On 7/20/2017 2:14 PM, Gareth's Downstairs Computer wrote:
Drove onto the field on Tuesday and was dismayed to
see a big banner marked Tomlinson, which portended
a bum job, but it turned out to be a scorcher being
a fence judge at the Dauntsey horse trials.

Taking my cue from the coupling loop that feeds a
mag loop antenna, and sitting pretty much under
the 400kV pylon line, I wondered about the possibility
of using a loop to couple into the electricity grid and
so giving the equivalent of a Beverage at 137kHz?

There is a lot yet to be fully understood about access to the LF bands
in the US. But if you are under a HV line, they might well be using the
line for carrying control signals for the power grid. The technology,
PLC, doesn't play nicely with ham usage.

How do you find whether a power line is using PLC? For some reason you
can't find anywhere a list of places that are OK, or that are not OK.
Instead you have go to a website and ask, and wait to be told yes or no.
So we (the hams) are in second place when it comes to sending
information over these lines.

(There is a fairly new line at something like 250KV close to my back
yard. I don't yet know whether it is carrying PLC.)
Bob Wilson, WA9D
As far as I know, in the USA we only have to inquire before operating
if we're located within 1 km of a power line.


Whereas here in Brit we have restrictions within 1/2 mile of any aerodrome.

But that's a restriction on antenna height (40 feet, I believe - but as I
don't live within 1/2 mile of an airfield, I haven't checked lately).

And it has nothing to do with technical matters, it has everything to do
with not getting in the way of the airplanes.

There was a similar law in Canada when I was licensed decades ago. I assume
it hasn't changed much, but I've never lived near an airport either, so it
never applied to me.

Do they restrict the height of trees as well?

Near my house the city wanted to extend the runway. The main road in and
out of town passes within some hundred(s) of feet of the end of the run way
with power lines. Someone paid to bury the power lines and they cut the
lighting poles down to about 7 feet as well as clearing a vacant lot across
the street. They even bought out a Waffle house a couple doors down the
street because it would have been too many people in the area around the
flight path. Some other businesses were allowed to remain because they
didn't have as many people in them typically.

The part I don't get is how they can ignore the traffic on that road.
School buses run by there every day full of kids and standing taller than
the lighting poles. I don't get how all this was reasoned out, why one
thing would be mitigated and other things not.

--

Rick C