[Elecraft] High Current only on 20 Meters

[David Gilbert]

Completely true.  According to TLW, 1,000 feet of RG-58 with a dead 
short on the far end will also have a 1:1 SWR at the near end.  Even 500 
feet will have an SWR less than 1.1:1 at the near end.

In fact, as little as 100 feet of RG-58 will turn a 2:1 SWR at the far 
end into roughly 1.5:1 at the near end even at 14 MHz.  All of the 
difference is line loss, although I'm sure someone would point out that 
it's "only" about 2.2 db worth and doesn't really change the SNR for 
receive on this end of the path (not true on the other end of course).

73,
Dave  AB7E



On 3/4/2020 11:15 PM, Jim Brown wrote:
>
>
> Remember I said that VSWR in a system is set by the load (the antenna) 
> and is decreased by the loss in the line. If the line is long enough 
> and mismatch is great enough, the VSWR eventually ends up a 1:1. I've 
> used this example as an extreme case: a 1,000 ft spool of RG58 with a 
> 10K ohm load would look like a perfect 50 ohm load to a transmitter at 
> 28 MHz, the SWR would read 1:1 at the transmitter end of the line, and 
> loss in the feedline would be huge.
>
> 73, Jim K9YC