On Thursday, December 18, 2014 2:13:00 PM UTC-6, Channel Jumper wrote:

One other thing - as Columbo would say, the SWR meter does not indicate
resonance, it only tells you what the feed line tells it. 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.

If changing the length of the coax makes large changes in the SWR,
that just shows you have poor decoupling from the antenna to the
feed line. Need a balun or choke, or a better balun or choke than
what is being used.
What you state is largely a CB radio wives tale, due to most of them
not properly decoupling the antenna from the line.

With proper decoupling, the length of the coax will have little
bearing on the SWR seen at the rig. It will be the same as what is
seen at the antenna input, minus any decrease in SWR due to coax
loss. IE: very high coax loss can make anything look good at the rig.