The increasing swr with a 50ohm feed is good news. Rg is being lowered
and efficiency is going up. Most ham references say 32 radials are the
point of diminishing returns. Then an UNUN plus a good choke are the
easiest, most WX resistant, and lowest loss way to feed the antenna,
somewhere between 12 and 20 ohms most likely. Check with Balun Designs
for what they can make or stock once your feedpoint impedance approaches
your limit of radial effort or space or $.
Grant KZ1W
On 2/6/2023 10:03, Jan Erik Holm via TowerTalk wrote:
Or stub matching / SM2EKM
Den 2023-02-06 kl. 17:41, skrev john@kk9a.com:
You can also match the impedance using a hairpin match.
John KK9A
Michael Tope W4EF wrote:
Dennis,
Once you figure out what your impedance converges to as you add more
radials, you might be able to bring the VSWR back down to something more
acceptable with an Unun transformer. I have a 55ft top-loaded vertical
for 160 meters. The feedpoint impedance with a dense radial field is
about 12 ohms (VSWR > 4:1). With a 4:1 Unun transformer, the VSWR
improves to 1.1:1 at around 1830 KHz. The 2:1 VSWR bandwidth is about
~50 KHz. I got the unit I have from Balun Designs.
73, Mike W4EF...............
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