I've been hearing "where are the answers to these 20 true/false questions?
And many of the slides on my PPT or PDF end with a QUESTION.
ALL 20 of the TRUE/FALSE question are TRUE - or true enough.
They were meant to foster a discussion during a PPT showing, which they do.
If feed lines had ZERO attenuation, then an antenna "tuner" could be in your shack, or right at the antenna terminals to provide a match. It would make no difference. Walt Maxwell's (W2DU) books make that abundantly clear. One should worry less about SWR value, and worry (not so much) about attentuation in your choice of feed line).
With reasonably low-loss feed lines (like RG213 or window line on HF bands) the "additional loss" when you have SWR values from 2 to 5 are not worth worrying about, as long as your rig can deliver full power. That is especially true on 80 meters, where everyone faces the issue of opertating at the top and bottom of the band. My favorite frequencies are below 3585 and above 3990 kHz (EMCOMM nets).
Personal Observation
What I find fascinating is watching a Smith Chart "rotate" around a constant SWR circle as I added small amounts of transmission line (2-20 feet of RG213) but the SWR, RETURN LOSS, and REFLECTION coefficient all remained the same. Yes, there is a small amount of additional attenuation from extra coax.
I attempted to explain why the impedance changes in terms of the analogy of "grampy pushing a grandchild on a swing - phase, phase, phase". We all get that image. How many of us "see" why the voltage and current get out of phase with reactance (antenna is too long, or antenna is too short)?
So I have to keep reminding myself, the Nano VNA is measuring impedance not of my antenna itself but of my entire antenna system including X feet of coax (assuming an imperfect match).
I'm now plaiying with doing the initial "calibration" not at the VNA SMA terminals, but with using 100 or 150 feet of RG213 (Short/Open/Load).
Thus, afteer moving the calibration plane to a distance of 100 ft of RG213, I can "see" what is happening right at the antenna terminals.
I know the calibration process allows me to do that with Nano VNA Saver as well.
My sense is that there is more to measuring impedance, phase, SWR, etc. than one is led to believe.
Still learning as I go, and enjoying the process.
It's just like that stethoscope - a fun gadget to play with.
Barry k3eui
Barry K3EUI