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Author Topic: Navel antennas in parallel  (Read 386 times)
KJ6TSX
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Posts: 400




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« on: April 16, 2019, 09:29:26 PM »

I was visiting Pearl harbor last week and had the privilege to check out the USS Missouri. Of course I was interested in the antennas and noticed what appeared to be three dipoles in Parallel, they all appeared to be the same length and fed very close to the end of the antenna.
Wanted to know if any of you guys have the inside scoop on what they did?? and if the three antennas were in parallel what would be the advantage?

Thanks
George
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WB6BYU
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Posts: 18535




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« Reply #1 on: April 16, 2019, 09:41:41 PM »

Fat antennas (using multiple wires) have wider bandwidth.

Specifically it reduces the impedance when the antenna is close to 1/2 wavelength (or a multiple
thereof) making it easier to feed / match.


"Navel" antennas, however, are different, as a belly button doesn't make a good ground connection.
« Last Edit: April 16, 2019, 09:56:57 PM by WB6BYU » Logged
KOP
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Posts: 346




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« Reply #2 on: April 16, 2019, 11:04:36 PM »

ask these guys
https://www.qrz.com/db/NI6BB
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I considered a microwave oven magnetron and a 4' dish as a drone-killer. The ERP would be on the order of a hundred thousand watts or so. ~anon

November 28, 2018, 09:16:04 AM
G3RZP
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Posts: 1324




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« Reply #3 on: April 17, 2019, 04:44:19 AM »

Especially at LF, increasing the capacity to ground of an antenna means less series inductance is needed for matching, so less toss. The same thing as a mobile whip with a capacity hat. Back in the days when maritime services sued around 2 MHz, it was not uncommon to see two inverted L antennas about 20 feet long in parallel on a small fishing boat. Similarly for mobile military installations, where you could see two whip antennas in parallel, each at an angle of 45 degrees or so to the vertical.
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N3DT
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Posts: 1793




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« Reply #4 on: April 17, 2019, 06:59:35 AM »

McNamara's Naval Destroyer. A hoola hoop with a nail in it.
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