[TowerTalk] RG6

Jim Lux jimlux at earthlink.net
Tue Sep 11 20:33:52 EDT 2007

Jim Brown wrote:
> On Tue, 11 Sep 2007 16:26:15 -0400, Jim Jarvis wrote:
>> I'm wondering if anyone has worked with RG6 for power
>> transmission, or might know the limitations.
> There are many different variations on RG6, just as there are many 
> different variations on RG59, RG6, RG8X, and RG11.These variations 
> affect power handling and loss. An RG6 designed for CATV/MATV use is 
> likely to have pretty low loss, but may handle only several hundred 
> watts. Power handling is also strongly affected by VSWR -- voltage 
> peaks can cause dielectric breakdown, and current peaks can cause 
> excessive heating due to I squared R losses. Power handling is also 
> a function of frequency. 

Fed from a 75 ohm source, worst case voltage would be twice the matched 
voltage (full reflection), likewise worst case current is twice matched 

However, if you have reactive components at both ends of the line, you 
can get much higher (MUCH, MUCH higher, if the loss is low) because of 
the circulating power (consider a short length between a L with a Q of 
100 and a C with a Q of 1000.. you've basically got a tuned circuit with 
a Q of about 100, so the voltage will be 10 times the voltage being fed) 
  Basically, it's the same sort of resonant rise you see in any tuned 

Jim, W6RMK

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