On 12/19/2014 10:14 AM, Jerry Stuckle wrote:
On 12/19/2014 2:33 AM, Jeff wrote:
By changing
the length of the coax you can make the antenna appear as being resonant
or non resonant, even though the antenna may or may not be a perfect 50
ohm load.

Incorrect, changing the length of the feeder will not change the SWR
beyond any extra loss in the cable. It will change the phase of the
mismatch that is all; (rotate around a constant VSWR circle on a Smith
Chart).

Jeff


Incorrect. The basic VSWR meter measures the voltage, not the power.
And if the SWR is other than 1:1, this voltage will change depending on
the distance to the mismatch.

Additionally, a shorted coax 1/2 wavelength long shows a short (0 ohms).
But a shorted 1/4 wavelength coax shows an open (infinite impedance).
Somewhere in between (I'm not going to bother to figure out exactly
where because it's not that important) it will show an effective 50 ohm
impedance.

Please bother. It is important to me to understand these things. And are
you saying that there is a length of transmission line that will satisfy
both the shorted and open conditions. What do you mean by "effective"?
Are the lengths different in the two cases? Please help and thanks.


Coax length is unimportant when you have a 1:1 SWR, but if you don't,
the coax will act as a matching network. And length will affect the
overall system.