> >> > >>Robert Leclercq wrote:

 >> > >>>
 >> > >>>Was looking into coax of that size yesterday for an industrial
 >> application. It doesn't go much higher than 2-3KV in breakdown
 >> voltage. Not what you want. Robert
 >
 >> > >>Try type N coax.
 >> > >>
 >> > >>PauLamar

 >> Is that a silicone insulated coax people? Otherwise the electrical
 >> requirements may be met while the stuff melts in side the cowl.
 >> Bill Jepson
 >
 > I think you get it with teflon. Not exactly flexible :)
 >
 > Paul Lamar

Matt Prather wrote:

 The purpose of coax has been to convey high frequency signal power
 between two RF devices.  The most important features are the matching
 of impedance (for best power transfer), and picking a dielectric
 media that reduces frequency dispersion (allowing higher frequency
 content - bandwidth).

 Yes, ideal ignition wires efficiently convey high power, but if high
 frequency content is filtered out, all the better - the spark plugs
 won't know the difference.  And it's this high frequency content which
 gets into our AM VHF comm radios and strikefinders (if you are lucky
 enough to have such a thing).  The filtering of high frequency content
 from the ignition system is the reason for the helical wound wires.

 As anecdotal evidence, if coax was better for horsepower, you would
 see car's like Corvettes and RX8s with it.  Instead, they have gone
 the smarter route and used very short sections of high tension wire
 running from coil-per-plug ignition.  This is the best bet for custom
 built aircraft too.  The shorter the wire, the less there is for
 losses.

 As further anecdotal data, I run MSD CDI igntion on my O-200 with fairly
 long wires between the coils and the plugs.  I use Moroso helical wound
 wire I bought at the local Schucks.  It works great, and makes less
 ignition noise (by far) than the Bendix mag that runs the other
set of plugs.

 I'd say, save your neat-o, high dollar coax for running radios - use
 RG400 for that.

 Regards,

 Matt-
 VE N34RD, C150 N714BK

   Yes I run three MDS-6A unites with MSD wires on my coot and there
is no ignition static at all, the hotter the ignition is the cleaner
it is, mags are weak dirty and noisy.

   Ken Welter

 
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