"Roy Lewallen" wrote in message
...
Owen Duffy wrote:
"Ralph Mowery" wrote in
:
http://www.davisrf.com/ham1/coax.htm

Greg's notes on Buryflex at
http://www.seed-solutions.com/gregordy/Amateur%
20Radio/Experimentation/buryflex.htm are also interesting.

I have a 100 foot piece of Davis Bury-Flex I bought new and measured on a
network analyzer. At around 200 MHz and above, it acts very strangely. The
loss is 3 or more dB/100 feet above its spec. But if I take its natural
two foot or so diameter coil and flex it a bit, the attenuation increases
another couple of dB and stays there. When I check again some days later,
I find that it's returned to its lower but still way out of spec value. It
seems to be ok for HF, but I sure wouldn't use it above 2 meters. The
genuine LMR400 I have is within its spec and doesn't exhibit this strange
behavior when flexing.

Roy Lewallen, W7EL

That is interisting. I bought 500 feet and cut it into 4 lengths from about
120 to 140 feet each. They were then rolled into coils about 2 or 3 feet in
diameter. Two of them had pl 259 plugs on them and the other two had N
connectors installed. I did not use any high teck equipment, just about 100
watts at 440 mhz, a bird wattmeter, and a good dummy load. The losses in
each piece was within the specificiations of the coax. The same meter was
moved from one end to the other to see how much power was lost.
This was done mainly to see if the connectors were installed correctly as
it would have been difficult to change it out after the antennas were
installed.
It has been up almost a year. Wish I could pull it down and recheck it to
see if it was acting up.