Sal salmonella@food wrote:

"Jeff Liebermann" wrote in message
...
On Tue, 27 Aug 2013 08:41:02 -0700, "Wayne"
wrote:

Today I saw a Time Warner Cable minivan trolling through the neighborhood.

It appeared to have a four antenna DF array on the roof with vertical
lengths of about 2-3 feet.

What's up with that?

It's a doppler direction finder array, used to locate cable leaks and
ingres (leakage into the cable). Something like these perahaps:

I didn't see the Cox survey van on my street but their tech paid me a visit.
I didn't appreciate the extent of it but my interior cabling was leaking.
The tech came to the door and said he had to do some testing on the pole
that would knock out all our services for a few minutes. Was that OK? (Yes)

He reported that my house was the source of leakage that had earlier been
detected by their vehicle. (Oops) He asked if we had any broadcast ingress.
(Yes) Could he fix things inside the house? (Heck yes) He spent over an
hour reterminating some of my old stuff and running a few new pieces for me.
That got the leakage within limits and it made the ingress go away. (Yay)

"Sal"

And all that in the house of (supposedly) a radio amateur?

Over here the house cabling is the responsibility of the inhabitant.
The cabling company delivers signal to a demarcation point, in new houses
usually in the electricity metering cabinet, in older houses that were
later retrofitted with cable it is often on the outside wall of the living
room. Anything connected there you have to supply and maintain yourself.

The inhouse cabling and especially the connectors have been very
substandard at the time the cable network was deployed, which wasn't a
problem because there were few channels and they were positioned carefully
not to overlap with terrestrial transmission in the area. But when the
DVB-T network was deployed, new channels were used (there was parallal
Analog and DVB-T transmission for a while) and the cable networks were
fully allocated. So you often got a DVB-T transmitter on the same
channel as an analog cable channel, and those DVB-T transmitters are
in the cities instead of the usually more remote sites where the Analog
transmitters were.

Big trouble ensued, and everyone (who cares about picture quality)
was forced to buy new cabling and at least new connectors, that were
actually providing shielding.

This was a big boon for radio amateurs, because it reduced the amount
of all interference, not only from DVB-T to viewers but also from
radio amateurs to viewers and from the cable network to radio amateurs.
(on the cable network, channels are in use that overlap with the 2m
and 70cm amateur bands)