That antenna is not the best with only 3 "stingers" as a skeleton image
plane. It's pretty spartan!
The "wiggles" you are seeing at the end of the coax reflect a small SWR on
the coaxial line. The antenna is not strictly 50 ± j 0 ohms. As such, the
wiggles are due to the standing wave within the coax due to a slight
mismatch. But have a look at your cursor at "resonance". The trace is
nearly flat surrounding the cursor. Nothing to be concerned about. Your
NANOVNA is showing you the correct rendition of the response of the antenna
connected to your 50-ohm coaxial line.
Dave - W?LEV
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On Thu, Feb 6, 2025 at 11:46?PM jeffinwa via groups.io <k7jsm=
[email protected]> wrote:
When I am constructing an antenna, I have been using this device to plot
the swr in my shop. I usually set a wide enough bandwidth to easily see
the dip at resonance.
In the shop, connecting this device directly to the SO239 connector, the
sweep on the screen is perfect. But in testing with the antenna installed
with coax, and testing at the end of the feed line, the sweep seems
strange. See attached
--
*Dave - W?LEV*
--
Dave - W?LEV
