[TowerTalk] Mosley Antenna Question

[TexasRF--- via TowerTalk]

True, the loss is related to conductor resistance. But, in a given size 50  
ohm cable, such as the .405" diameter sizes, RG213, LMR400, 9913 etc., the  
dielectric constant dictates the center conductor size. 
 
The low density foam dielectrics require a much larger center conductor to  
maintain a 50 ohm impedance and the lower losses are a result.
 
So, indirectly the dielectric does contribute to the loss in a given size  
cable.
 
I agree, 7/8" Heliax type cable is wonderful stuff. There must be millions  
of feet in surplus these days.
 
73,
Gerald K5GW
 
 
 
In a message dated 2/17/2015 8:38:06 P.M. Central Standard Time,  
jim at audiosystemsgroup.com writes:

On  Tue,2/17/2015 1:30 PM, Ed Sawyer wrote:
> I can tell you one reason to  spec RG213 over LMR400 to feed your Mosley
> tribander, or any other  tribander for that matter.

There are some misconceptions here that are  the result of advertising. 
Loss below about 500 MHz is entirely due to the  resistance of the 
conductors at the frequency of interest. The dielectric  does not 
contribute to loss below that frequency unless it's wet, and if  it's 
been wet, the braid is probably degraded, increasing copper loss.  :)

If you really want low loss, use hard line. I'm feeding my SteppIR  with 
350 ft of 7/8-in. :)

73, Jim  K9YC
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