View Single Post
  #510   Report Post  
Old March 20th 06, 03:56 PM posted to rec.radio.amateur.antenna
Cecil Moore
 
Posts: n/a
Default Current through coils

Richard Harrison wrote:

Are any famous authors protagonists of that theory?

In "Fields and Waves in Modern Radio", Ramo and Whinnery, 2nd
edition, there is a section titled: "9-16 The Idealized Helix
and Other Slow-Wave Structures". Quoting: "A rough picture
would convince one that the wave should follow the *wire* with
about the velocity of light, ..."

From the IEEE Dictionary: "slow-wave circuit - A circuit whose
phase velocity is much slower than the velocity of light. For
example, for suitably chosen helixes the wave can be considered
to travel on the *wire* at the velocity of light but the phase
velocity is less than the velocity of light by the factor that
the pitch is less than the circumference."

a 75m bugcatcher loading coil is a slow wave structure with
a velocity factor around 0.017 (calculated and measured).
--
73, Cecil http://www.qsl.net/w5dxp