Copper Talk » Product Reviews » Antennas » Matching ring at bottom of Maco 5/8 question « Previous Next »

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Maxgain
Junior Member
Username: Maxgain

Post Number: 17
Registered: 3-2007
Posted on Thursday, April 12, 2007 - 8:40 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)
On the Maco 5/8 ground planes they use a "ring" that is tapped to make the antenna work.

This ring coils around the antenna's base one turn.

On other 5/8 wave vertical antennas I have seen a similar type of feed/matching system but in these cases the "ring" coiled around the antennas base about 3 or 4 times and tapped just like the Maco desighn and was about the same diameter.

Both of these desighns were used on vertical antennas that are both 5/8 wave.

Why do they use a different amount of turns in the "ring" for the same wavelength antenna?
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Tech833
Moderator
Username: Tech833

Post Number: 1656
Registered: 8-2002
Posted on Friday, April 13, 2007 - 10:30 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)
The Maco ring is larger in diameter than those antennas using multiple turns. What you are after is the correct length of material between the coax center and the ground (current zero) node. It reduces the resistance at the feedpoint so the high impedance antenna matches the low impedance coax. That is all.

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