And the Tooth Fairy was the CFO, and Santa Claus was ther CEO. And
they got busted for breaking Ohm's Law.


On Tue, 19 Jul 2005 10:01:30 -0400, "Don Baker"
wrote:

Henry:
From: http://www.nrcdxas.org/articles/coax.html

The recent popularity of a new antenna cable called Skyhighgain Coax has
created a safety problem for users and a nightmare for firefighters. SHGC
was developed theoretically by Tricenters Experimental Laboratories, Inc. as
a signal-boosting element for use in radio and television transmission
lines. Scientists at TELI discovered that when a bias voltage is applied to
the special material used to make SHGC the effect was incredible. Instead of
simply reducing signal loss, the signal strength increased!

Amplification of RF (radio-frequency) signals in the new coaxial
transmission cable was actually greater than 3 db (decibels) per meter per
meter. (Read that again.)

In laymen's terms, that means that for every 10 centimeters a signal travels
through the cable the signal strength doubles! Put 1 Watt of RF energy into
one end of a one meter length of SHGC and you get 2 Watts at the other end
(assuming you supply the bias voltage, of course). At two meters you get 4
Watts. At three meters the signal strength increases to eight Watts.
Doubling the power every meter the total effective power of the signal
exceeds 1,000 Watts by the time it has traveled only 10 meters up the line.

Now imagine what would happen if you had a 100-meter SHGC cable. (The actual
figures are shown at the end of this article.)

In conventional transmission lines there is always some loss of signal
depending upon frequency and the electric characterists of the cable. But
with SHGC, instead of a loss, you get a gain in signal strength. This is the
stuff every radio engineer has dreamed of.

But here's the problem. The unwary (and mathematically challanged) average
user seems to think that if a short section of SHGC inserted in his
transmission line is good, then a longer one is better. If one were to, say
substitute SHGC for the complete run from their radio shack to the top of
their tower, the signal would have more energy than the cable (or the
antenna) could withstand. (The 20-meter traps on the tri-band beam that used
to be on the 60-meter Rohn 25g tower behind the house in the photograph
above were never found.)

Designed to be used in short sections between standard coax and the antenna,
SHGC is not currently available, pending the resolution of certain limiting
manufacturing capabilities. Some reports have surfaced however that a few
samples of the hot-pink colored coax have somehow slipped past reality
checkpoints and made their way into the Amateur (and amateur) community. And
without official spec sheets and installation guides SHGC poses a
significant hazard to the uneducated.

The following table dramatically illustrates the danger of using too much
Skyhighgain Coax in any transmission line.

Length of Coax / Power Output

1 meters - 2 Watts
2 meters - 4 Watts
3 meters - 8 Watts
4 meters - 16 Watts
5 meters - 32 Watts
6 meters - 64 Watts
7 meters - 128 Watts
8 meters - 256 Watts
9 meters - 512 Watts
10 meters - 1,024 Watts
11 meters - 2,048 Watts
12 meters - 4,096 Watts
13 meters - 8,192 Watts
14 meters - 16,384 Watts
15 meters - 32,768 Watts
16 meters - 65,536 Watts
17 meters - 131,072 Watts
18 meters - 262,144 Watts
19 meters - 524,288 Watts
20 meters - 1,048,576 Watts
21 meters - 2,097,152 Watts
22 meters - 4,194,304 Watts
23 meters - 8,388,608 Watts
24 meters - 16,777,216 Watts
25 meters - 33,554,432 Watts
As you can see, by the time you reach only 20 meters, the signal power has
exceeded a million Watts! Assuming your facility's commercial power mains
could handle the load, the signal would exceed 30 million Watts at only 25
meters from the transmitter.

Of course, most power main breakers would trip long before the million Watt
level, but once the signal starts up the transmission line the peak envelope
power (PEP) climbs so fast that there is a possibility that the circuit
breakers would either fuse or the electric current would simply jump the
breaker's open switch gap and power would continue to increase until the
primary main lines evaporated in what could only be described as an
artificial bolt of lightning, showering every surrounding structure in hot
plasma and sparks.


"Henry Kolesnik" wrote in message
. ..
At the OKC hamfest I got a piece of neat looking coax that is double
shielded with silver braid, with a sort of clear pink outer cover. It has
connectors so I don't know the thickness of the center conductor.
It's stamped with the following characters:
68999, AA-2831. 81205, 204-15578-1, AUGUST 1996

I asked the seller, an ex-Boeing employee about it and he said it's the
same
kind as used in Air Force One. He couldn't recall the specs but said it
was
Teflon, good to a Gig but he had used it outdoors. for 2 meters and 440.

Can anyone tell me more or point me to a site?
tnx
--

73
Hank WD5JFR


I've tried to find the specs but get only one hit googling::
http://www.waea.org/tech/techdocs/SatSpec0798V1.doc

This site kind of confirms what the seller said.