Re: belkin power conditioner for my Samsung LCD - is it worth it???

Of course coax can carry more current. Not relevant. That says
nothing of minimal leakage into the center conductor. Disappointing
is why this basic concept is unknown here. This was discussed in many
places including rec.radio.antenna. amateur - maybe in posts from
Richard Harrison. I have long since forgotten how often this
knowledge was discussed.

Even a coax cable with minimal and leaky shielding permits minimal
current in center coax. A concept even demonstrated in a first year
EM Wave course.

Cable companies say same thing. They told piggy that a $90 belkin
was best not used. Obviously. Are you saying cable companies are
lying? As explained here repeatedly and made so obvious in 1st year
EM Wave course, as well as evident in parameters in the telegrapher's
equation - the coax center core is shielded from surges outside the
cable. Cable TV cable has better shielding. Then the cable has
double layers of that cable shielding. Then both ends of that cable
have surge protection.

If radios do not routinely contain RF amp protection, then every car
radio and cell phone in the vicinity of a lightning strike would be
destoyed. Then static electric discharges would routinely damage all
radios and TVs. Why are transistors that could even be damaged by a
few volts not be harmed when a human discharges 18,000 or 20,000
volts? Welcome to protection routine in all transistor radios. Just
because one radio fails (a defective design) means routine protection
does not exist?

The cable guy is correct. That $90 belkin does nothing useful. An
earthed cable means that cable surges do not enter the building.
Anything that might leak through double layered shielding is made
completely irrelevant by protection routine in RF amp circuit
designs. This protection was integrated even inside the tuner of a
1950s TV. Made even better as semiconductors replaced tubes.

Why do cable companies now properly install (earth) that cable?
Cable must provide service equivalent to or exceeding reliability of
POTS (phone service). If that $90 belkin did something useful, then
cable company would install those $0.10 or $1 parts. If those
differential surges existed as assumed, then cable companies would
waste no time installing those $0.10 parts to make it irrelevant. How
curious. That protection is already inside cable amplifiers and in
household cable appliances.

Notice how massive that profit margin on a $90 belkin. Add some
$0.10 parts and sell it for how much more? Just another reason why a
plug-in promoter will post anything here to deny technical reality.

Why do you completely ignore all car radios and cell phone destroyed
by nearby lightning strikes - zero. Zero because RF amp circuits
already include protection. I even remember it in *** Tracey wrist
radios. Why ignore shielding even found in a poorly shielded buried
coax cable? Why ignore protectors already installed at both ends of
every coax cable? Why ignore what cable companies - most concerned
with reliability - say about that $90 belkin? Why make claims that
contradict what was even discussed in rec.radio.antenna.amateur?

Protection is defined by a single point earth ground. Whereas other
utilities must earth every wire in every cable via a protector - a
shunt mode device - instead, cable needs no such protector. If a coax
wire terminates at an antenna where its center core connects to
exposed antenna elements, then an earthed center core protector might
be useful. But that expsosure does not exist in cable service. In
cable TV service, cable center core connects to protection even inside
cable amplifiers.

On Aug 20, 11:20 pm, phil-news-nos...@xxxxxxxx wrote:
,,,
This doesn't make any sense. Coax can carry a _lot_ more current than
that. It can carry massively _huge_ amounts of current if you don't
mind destroying it in the process.
...

Voltage is important when dealing with differential mode. If a surge
is in common mode up to a point where the shield is connected solidly
to ground via a short wire, from that point on it can be mostly
differential mode. The voltage that would be developed with depend
on the current, of course. But the maximum voltage you could get is
the voltage the insulation would still hold back against a breakdown.
...

My first experience with lightning destroying a radio was when I was
about 13 years old. I was listening to a portable radio inside during
a thunderstorm. The telescoping antenna was up about 2 feet long.
A lightning strike occurred at the far end of the back yard, which was
about 80 or 90 feet away. The radio just went dead and never worked
again, other than being able to produce some hiss to the speaker at
full volume.

Such protection is not routinely in radios. I can't say there is no
radio that has it. But none of the dozen or so I have taken apart
had any.
...

Earthing only the shield of the coax and providing no other protection
is only partial protection of the coax.

BTW, I'm tiring of this repetition. We don't 100% disagree or 100%
agree. It appears we shall have to leave it at that. It takes quite
some time to post these extensive replies, and we aren't getting anywhere
at all with this.

.

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