SNIP
>No, it is not erroneous. This is from an engineering handbook. A
>1.5:1
>VSWR will reflect 4% of your power. You can calculate that. That 4%
>of
>power goes back down your coax where it weakens do to coax losses. It
>
>then sees a mis-match of some sort when it arrives back at your
>antenna
>tuner/pa. Some of that power is sent back into the antenna tuner/pa
>and
>some is reflected again to go back up the antenna. So whatever power
>is
>no reflected back to the antenna is reduced by the loss in the coax
>and
>then when it gets to the antenna, 96% of it is sent out and 4% is
>relected back to do the same thing. Reflections basically go back and
>
>forth continually ad infinitum. This is why it is called a Standing
>Wave.
>
>Is your total power loss 4%? No, I never did say that.
It was hard to understand what you meant. I prefer to use dB, not some
percentage which is meaningless unless you know all the other parameters.
Saying that 4% goes round and round forever is gross over simplification.
But SWR does
>add
>to the loss in your system.
Thats what I TRIED to show later down the page.
>I am willing to go round and round on this one.
Dont bother. When taken in the proper context you are correct.
I am an RF engineer
>both
>by degree and trade. So I feel that my knowledge is sufficient.
So is my son, now going for his MSEE; but no one has questioned your
credentials so why bring it up?
One can be a truck driver and read the charts that are
available...developed by some EE I assume.
>
>Fortunately on HF, coaxial line loss is not a huge problem unless you
>have a monster length feed line. On VHF and UHF however, losses can
>be
>significant.
Basic facts.
>
>>Here are the published flat and additional VSWR losses for RG-213 per
>>100':
>>
>>Freq Flat Loss Add loss 2:1 VSWR Add for 4:1 VSWR
>>4 Mhz 0.32dB <0.1dB 0.3dB
>>15 0.8 0.18 0.7
>>30 1.2 0.22 0.9
>>
>>It would then appear that even a 4:1 VSWR at 20M is of no real
>>consequence for many styles of operating. On 80M I really could care
>less
>>about the.3dB when I go from CW to SSB.
>
>I don't fully understand this chart. But the columns aren't aligned
>properly so I can't read it either.
The chart lines up here even after returning via the reflector; if others
are having a problem let me know. Anyway all I did was copy published
RG-213 loss and then add in the VSWR loss as published in any ARRL
Handbook or Antenna Manual for as long as I can remember.
Doesn't require no degree to read it either.
SNIP as the rest is off the cable loss discussion.
73 Carl KM1H
>Jon
>KE9NA
>
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