And that is how it’s done. Absolutely Impossible to disagree with
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7' Skipshooter (Pictures and measurements)
- Thread starter 2NC995
- Start date
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EZNEC VERSION 5.0 SOURCE DATA
"42.44, X = -20.44 ohms = 1.598 SWR."
R42.44 -jX20.44 ≠ 1.598:1 SWR
Z = sqrt Rsq + Xsq
Z = sqrt 42.44sq + -20.44sq
Z = sqrt 1801.1536 + 417.7936
Z = sqrt 2218.9472
Z = 47.10570241488816 ohms
SWR = 50 / 47.10570241488816
SWR = 1.061442616004747
SWR = 75 / 47.10570241488816
SWR = 1.59216392400712
Ref: https://www.worldwidedx.com/threads/7-skipshooter-pictures-and-measurements.253558/#post-714430
"42.44, X = -20.44 ohms = 1.598 SWR."
R42.44 -jX20.44 ≠ 1.598:1 SWR
Z = sqrt Rsq + Xsq
Z = sqrt 42.44sq + -20.44sq
Z = sqrt 1801.1536 + 417.7936
Z = sqrt 2218.9472
Z = 47.10570241488816 ohms
SWR = 50 / 47.10570241488816
SWR = 1.061442616004747
SWR = 75 / 47.10570241488816
SWR = 1.59216392400712
Ref: https://www.worldwidedx.com/threads/7-skipshooter-pictures-and-measurements.253558/#post-714430
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Marconi read those numbers from a modeling program, and the program is, in fact, accurate.
You made the mistake by dividing the absolute load impedance (or Z) from 50 ohms. This is not the correct next step.
Below is a link to a web site that both has a calculator, and shows the actual math behind it...
https://chemandy.com/calculators/return-loss-and-mismatch-calculator.htm
The DB
i m running a 5 foot skipshooter on the roof of my personal vehicle..works great !! especially where ilive lots of hills and valleys...ive tried most of the fiberglass antennas and this one is by far the best...its only downfall i see is its not as broadband as say a 10k, mr.coily, ,monkeymade,ect..and it wont handle the output of the big coil antennas either..but for tx and rx there every bit as good as the open coils maybe even better in the valleys less dropouts
The skipshooter antenna should handle 10000 watts considering souly by the construction and material the antenna is made from.
As facts still remain that the longer the antenna and spacing of the wire wrap can be the differance between a little heat and no heat at all when 10000 watts keys down into it.
I have witnessed the 7 footer withstand about 7500 watts avg and peak 8000 watts and 10 hours of talk time in 1 night.
The antenna never warmed up and swr stayed under 1.5 under max load.
I beleive this antenna would never have any issues at all as long as the antenna is away from everything as much as possible to eliminate as much reflection pissible on this antenna when pushing 5000 or better would malfunction and heat up quikly.
My winess of this action took place on top of a big hill in appalachia where nothing around the antenna to reflect on for 2 miles
As facts still remain that the longer the antenna and spacing of the wire wrap can be the differance between a little heat and no heat at all when 10000 watts keys down into it.
I have witnessed the 7 footer withstand about 7500 watts avg and peak 8000 watts and 10 hours of talk time in 1 night.
The antenna never warmed up and swr stayed under 1.5 under max load.
I beleive this antenna would never have any issues at all as long as the antenna is away from everything as much as possible to eliminate as much reflection pissible on this antenna when pushing 5000 or better would malfunction and heat up quikly.
My winess of this action took place on top of a big hill in appalachia where nothing around the antenna to reflect on for 2 miles
Thanks again 2nc995 for providing me an internal view for the real 7' Skipshooter mobile antenna. I used these pretty comprehensive details to effectively model the antenna with Eznec.
That said, This model of the 7' Sharpshooter has a slanted down radial ground plane, not mobile vehicle body. Also, the model posted above does not show a nice low match, but it is good enough for government work.
Thanks for all the comments.
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Here is the tuned version of the 7' Skipshooter. I'm hopeful to get the complete PDF file to post. Use the <> to move from each PDF file. Doesn't look like it use to, but I haven't figured out the new software. Sorry
Should be 11 PDF views, but only 10 posted. I guess there is a limit.
Eddie
EDIT: I added the 11th PDF image, the last image the image is the source (Matching details) and is titled "2nc995 TrskipshooterTuned 3."
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