[Elecraft] KAT100 and external watt meter question

Fri Jan 31 18:50:01 2003

With TLDetails, I found a combination of R and X for the load that
produced a 10.3 dB loss in the RG-213 coax for a length of 100 feet on
20 meters, and produced an SWR of about 11:1. I didn't have to
calculate it - took the easy way out!   <:}

IF you want to do it manually, get a Smith chart and start fishing for
values of load that result in the SWR that will give 10.2 dB loss in
100 ft of RG-213 on 20 meters. The loss data comes from the tables in
the Handbook as Stuart suggested. But recall that there is a
semi-infinite set of combinations of R and X that will fit on that SWR
circle on the chart.

Hope this answers your questions. BTW, there are many good
transmission line analysis programs available these days. I just
happen to prefer TLDetails . . .

73/72, George
Amateur Radio W5YR -  the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489  IC-765 #2349 IC-756 PRO  #2121 IC-756 PRO2 #3235

----- Original Message -----
From: "Bozidar Benc" <[email protected]>
To: "Stuart Rohre" <[email protected]>; "elecraft"
<[email protected]>
Sent: Friday, January 31, 2003 5:32 PM
Subject: RE: [Elecraft] KAT100 and external watt meter question

> Yes, coax losses are easy to find
> (http://www.radiobooks.com/products/techinfo/coaxloss.htm for
example), but
> I guess that they are for the case when SWR is 1:1.
>
> What I would like to know is how George calculated the 10.3 dB loss
in his
> example.
>
> Bole
>
>
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]]On Behalf Of Stuart Rohre
> > Sent: Saturday, February 01, 2003 12:05 AM
> > To: Bozidar Benc; elecraft
> > Subject: Re: [Elecraft] KAT100 and external watt meter question
> >
> >
> > There is a loss table in ARRL Handbook for typical coax losses
> > under various
> > SWR conditions.  Also in many Antenna books.  Actually a good
> > question, and
> > there are likely such charts on the web.   Google.com search
keywords:
> > "Coax SWR losses" or similar combinations.
> > 72,
> > Stuart K5KVH