Topband: Coax velocity factor
W0UN -- John Brosnahan
shr at swtexas.net
Wed Mar 28 06:48:23 EST 2007
At 06:43 28-03-07, EP Swynar wrote:
>On 27th March Charles wrote...
> > Every time I get the same results: VF=84%. This just seems a tad high to
>me, especially when 75% is the published value for RG-6, though I know the
>VF of foam cable is higher. Anyone else get similar results when checking
>this type of cable?
The VF of solid-dielectric cables is much easier to control than that
of foam cables.
For a solid cable the VF is just a function of the properties of the
But for FOAM cables the VF is a function of the properties of the
AND the percentage of air bubbles in the material.
Reel to reel variations can be quite large in foam cables and even
the same reel can be significant. EVERY phase-sensitive cable made from foam
dielectric must be tested individually.
More information about the Topband