On 9/16/2012 8:17 AM, Dan Marotta wrote:
Nope.

As a lab experiment in my college days, I located a break in a very long
coax by timing a signal's reflection using an oscilloscope. An
undamaged line, terminated in its characteristic impedance will deliver
most of its power to the load. Reflections will be minimal. I'm
describing an ideal situation which, I know, is not possible. You're
describing a poory designed, built, installed, or maintained system
which, considering us glider pilots, is probably the norm.

"Mike the Strike" wrote in message
...
Yes, but all feed lines are lossy and at the frequencies we are using
here the lengths of coax are dumb-ass. We don't have an awful lot of
signal to begin with, so throwing half of it away is plain stupid. I
remember in my ham radio days a friend used an unterminated roll of coax
as a dummy load when experimenting up in the GHz range. The signal
barely made it to the other end, making a terminating resistor unnecessary!


Hi Dan - You are indeed describing an ideal situation; Mike was
describing a non-ideal situation. If you make the line long enough, it
will absorb all the power before it reaches the end of the cable; for
high frequencies (transponder and higher), "long enough" might be only
20 or 30 feet with low-cost cable.

Without knowing the specific cable used in the PF antennas, I can't say
they are significantly degrading the signal, but shorter is better.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)