[Elecraft] SWR Readings:Differences

[Fred Jensen]

Just so we all don't confuse Mark, I think he asked a really good question,

If the coax is loss-less [we'll all let you know when you can buy that 
kind:-))], then what the other Fred said is true.  Unfortunately, all 
transmission lines, of whatever flavor, do have losses.  Compared to 
open wire lines, loss in coax is high.

In the early 60's at Keesler AFB, I passed my free time at K5TYP ... I 
enjoyed the people and the activity there.  We had a tribander that 
seemed to receive [sort of}, but we couldn't work anyone on it, and the 
SWR was 1:1 on 20, 15, and 10.  A puzzle.  During one of the testing 
sessions, someone swept the frequency from 10 down to 20 to go do it 
again, and the SWR was 1:1 all the way down.  Our coax had lain open on 
the ground for several years in Biloxi MS, and was full of water.  It 
was basically the longest dummy load in Harrison County MS before any RF 
got to the antenna.  And, it had a 1:1 SWR

Depending on the loss in your coax, your feedline will look more or less 
like a transformer.  More loss means it begins to dominate the 
transformer equation and your SWR at the shack looks better and better.

Again, the bottom line ... Don't stress about SWR unless it causes a 
problem for your transceiver.  If the transmitter is happy, so you 
should be.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

On 9/2/2014 6:57 PM, Fred Townsend wrote:
>
> Hello Mark: Question? What is the SWR of a mile long piece of coax if
> it is unterminated. Answer 1:1. That is because a long length coax
> will act as a matching transformer. Actually it doesn't have to be
> too long as you found out. If reading is not better in the shack
> something is wrong.