Topband: When is coax 'contaminated' beyond use?

[Chortek, Robert L.]

Hi Terry,

It seems to me that it ought to be fine to use the coax.   The fact the coax has more loss than non-contaminated coax shouldn’t matter, since the whole point is to dump the wattage as part of the 4 Sq. System.  Using lower loss Coax would only mean more power would get to the dummy load where it would all be dissipated anyway.  Total loss should be the same.  To my way of thinking it should not matter UNLESS the contamination is such that coax acts as an open circuit.

Others may disagree, but it seems logical to me.  OTOH, if it were me, and I was only using a very short length, I would spend a couple of extra bucks and use good quality components throughout my system.

73,

Bob AA6VB 

Sent from my iPhone

> On Feb 3, 2019, at 7:55 PM, terry burge <ki7m at comcast.net> wrote:
> 
> Hi Folks,
> 
> 
> A few years back some 9913 I was using apparently got water in the coax. I say this because of fluctuating SWR issues and I noted the shield when cut into was almost 'black'. So for my minor purpose of using spare coax for my dump power on an 80 meter 4-square can some of this coax be used? When I scrap the shield after exposing it with a knife will reveal the shinny copper again so is that sufficient to use some for reading dump power on my wattmeter at the shack? Seems if I try and get readings like what I had with the LMR-400 then it could be used. Coax is so expensive these days I want to use my valuable LMR-400 elsewhere if possible. And having a convenient way of reading dump power is of course important too.
> 
> 
> Terry
> 
> KI7M
> 
> _________________
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