[Elecraft] OT: Checking coax jumpers before soldering

[Ralf Wilhelm]

That kind of chart is e. g. in the ARRL antenna book (I have two older editions but am sure it is in both of them). Since the measurement assumes that the fraction of the power that is put into the line and not being converted into heat in the coax is completely reflected at the far end, it should work equally well with shorted or open end. I have a MiniVNA network analyzer that relies on this method for determining the electrical length and the loss of coax. Normally I leave the end open. 
However, I am not sure if it works very well with short pieces of low loss coax because of the difficulties of precisely determining a high s.w.r.

73, Ralf, DL6OAP

Am 12.11.2013 um 14:47 schrieb "Charlie T, K3ICH" <pincon at erols.com>:

> I remember seeing a chart somewhere that listed cable loss vs. SWR into an open (or was it shorted?) coax.  Just open or short one end, measure the SWR,  plug that value and the length into the chart to read the loss. Admittedly, this would be difficult for a cable already installed, but it would be an easy way to check an unknown piece in the junk box.
> 
> Anybody remember where that chart was published?
> 
> 73, Charlie k3ICH
> 
> 
> ----- Original Message ----- From: "bill conkling" <nr4c at widomaker.com>
> To: "Joel Black" <w4jbb at charter.net>
> Cc: "elecraft" <elecraft at mailman.qth.net>
> Sent: Tuesday, November 12, 2013 7:16 AM
> Subject: Re: [Elecraft] OT: Checking coax jumpers before soldering
> 
> 
>> I have used 50 ohm BNC 'terminators' with adapter to verify coax.  Start with terminator on analyzer, should be flat VSWR over wide band.  When at other end of coax should be same.
>> 
>> ...bill nr4c
>> 
>> 
> 
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