Nology

[Roger Heflin]

On Tue, 29 Dec 1998 jsg at donet.com wrote:

> 
> | the braids to anywhere on the block, frame etc, never exceeded 0.05 ohms
> | with a 4 lead sensing ohmmeter.
> | As an experiment after the PCM was replaced, I placed an oscilloscope on
> | the power antenna lead from my stereo.  With the stock wires, I had a clean
> 
> You can not measure RF impedance at DC as you found out. A shorted
> transmission line 1/4 wavelength long will have an infinite
> impedance. If you didn't know that, you would be surprised at what one
> can do with a few ferrite cores and some coax. Also, keep in mind
> that a slot in a large sheet of metal is an excellent radiator (a
> complementary antenna). The techniques that you use to test (and
> ground) at DC have little to no value at RF frequencies.
>

That is right, but, I spark is fairly close to an impluse, which means
it is fairly evenly distributed across the frequency range, so no
length would be the right lenght to elminate all frequencies, certain
length would eliminate some and make others worse.   I am not sure
given these sort of constraints that there would be anyway to not make
almost anything a RF radiator.   That is alot of why plug wires are
made the way they are.   I am not sure thing about it as a RF problem,
there is even a good way to shield things enough without going to 
extremes.

				Roger