[TowerTalk] Dielectric losses

[K3BU@aol.com]

In a message dated 2/1/02 4:25:04 AM Eastern Standard Time, W4EF@dellroy.com 
writes:

> 
>  C. ATTENUATION
>  
>  .......Attenuation is determined by the conductive
>  and dielectric losses of the cable. Larger cables have
>  lower conductor losses, reducing attenuation. Dielectric
>  loss is independent of size. Dielectric losses increase
>  linearly with frequency, while conductor losses increase
>  with the square root of frequency. Therefore, dielectric
>  losses become a larger proportion of the total cable loss
>  as frequency increases.
>  

The best definition yet, thanks Mike!

One other thing that comes to mind, in older cables there were problems with 
migration, where properties of the insulation between the center conductor 
and shield would be contaminated from the outer jacket (clearish plastic 
would become brownish), alter the dielectric constant and increase 
attenuation. Wires would remain without corrosion, attenuation would go up 
due to dielectric deterioration. I believe that present cables do not have 
that problem. It is worthwile to check the older coaxes by cutting piece off 
and checking the status of conductors and insulation, besides measuring the 
properties with TDR or analyzer.

Yuri, K3BU


After eating an entire bull, a mountain lion felt so good he started roaring. 
He kept it up until a hunter came along and shot him. 
The moral: When you're full of bull, keep your mouth shut.     
                                                                            
(-:  Will Rogers  :-)     
 

 

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