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[TowerTalk] Dielectric losses

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Subject: [TowerTalk] Dielectric losses
From: (Tom Rauch)
Date: Wed, 30 Jan 2002 08:59:50 -0500
> Brilliant!
> Just trust Tom that dielectric in the coax doesn't contribute to
> losses. Some "evaluation" of Force 12 products.
> Yuri

Dielectric losses in typical coaxial cables do not contribute 
significantly to loss at HF.

The primary loss mechanism is conductor loss.

The reason various dielectrics might *seem* to produce different 
losses is because the manufacturer, for a given overall diameter 
cable, can use a larger conductor when the dielectric has a larger 
percentage of air. Higher velocity factor cables, for a given diameter 
and impedance, have less loss because the center conductor is 

This really is well-known and widely published, but it is probably 
worth repeating because the myth that the dielectric is somehow 
responsible for dissipating significant (or even a majority of) power 
keeps popping up.
73, Tom W8JI 

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