Roy Smith wrote:
Tauno Voipio wrote:

The ratio of voltage and current of a RF signal in a transmission
line (called characteristic impedance) is fixed and determined by
the dimensions and materials of the transmission line.


Considering how much abuse the typical piece of coax absorbs over GOK how
many years of being scrunched into the rats nest of wiring behind most GA
panels, I suspect the characteristic impedance is anything but fixed.

As long as the scrunch is short compared to the wavelength
(in the cable, for coax about 2/3 of free-space wavelength),
the signal could not care less, and, for practical purposes,
the characteristic impedance is constant. If we have to take
the attenuation into account, the impedance is not even real,
but complex, containing capacitive or inductive components.

Not to mention that a lot of radio guys barely know which end of a
soldering iron to pick up. SWR Meter? That's the box which tells you how
****ty a job you did of putting the connectors on before you button up the
panel and write out the customer's bill.

You can also crash a new car before delivering it to
the customer ...

--

Tauno Voipio
tauno voipio (at) iki fi