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OK, it is the classic 2m 5/8 from the ARRL antenna handbook, but made a bit differently.

See pics...

First design:
I made a groundplane with two brass rods through PVC. Then I coiled some #12 wire around the PVC, then into the PVC through a hole and out the top. The center tap comes through the center of the PVC and coil, and then out a hole to a tap point. I monkeyed around with the tap point and overall length until I got a good match.

Second design:
I made a groundplane with two brass rods through PVC. Then I coiled some #12 wire inside the PVC, then straight out the top. I monkeyed around with the number of coil turns and overall length of the wire until I got a good match.

I actually measured about 6 dB improvement with the simpler, second design. The first is worse than a simple direct coax fed, vertical dipole, the second design is about 3 dB better than that dipole...

<blockquote data-quote="C2" data-source="post: 152047" data-attributes="member: 568">OK, it is the classic 2m 5/8 from the ARRL antenna handbook, but made a bit differently.See pics...First design:I made a groundplane with two brass rods through PVC. Then I coiled some #12 wire around the PVC, then into the PVC through a hole and out the top. The center tap comes through the center of the PVC and coil, and then out a hole to a tap point. I monkeyed around with the tap point and overall length until I got a good match.Second design:I made a groundplane with two brass rods through PVC. Then I coiled some #12 wire inside the PVC, then straight out the top. I monkeyed around with the number of coil turns and overall length of the wire until I got a good match.I actually measured about 6 dB improvement with the simpler, second design. The first is worse than a simple direct coax fed, vertical dipole, the second design is about 3 dB better than that dipole...</blockquote>

[QUOTE="C2, post: 152047, member: 568"] OK, it is the classic 2m 5/8 from the ARRL antenna handbook, but made a bit differently. See pics... First design: I made a groundplane with two brass rods through PVC. Then I coiled some #12 wire around the PVC, then into the PVC through a hole and out the top. The center tap comes through the center of the PVC and coil, and then out a hole to a tap point. I monkeyed around with the tap point and overall length until I got a good match. Second design: I made a groundplane with two brass rods through PVC. Then I coiled some #12 wire inside the PVC, then straight out the top. I monkeyed around with the number of coil turns and overall length of the wire until I got a good match. I actually measured about 6 dB improvement with the simpler, second design. The first is worse than a simple direct coax fed, vertical dipole, the second design is about 3 dB better than that dipole... [/QUOTE]

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