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The Curious Conundrum of the Dangling Dipole




 
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Author Topic: The Curious Conundrum of the Dangling Dipole  (Read 8455 times)
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WBear2GCR
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« Reply #25 on: March 01, 2015, 02:43:16 PM »


Pete,

I'm entirely unclear on how the ant that you suggests works?
If I understand it, what you've done is to make the end of the antenna "fat"??

As opposed to looping the end back under the main wire and not connecting the end back to
the main wire.

                      _-_-bear
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_-_- bear WB2GCR                   http://www.bearlabs.com
Pete, WA2CWA
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« Reply #26 on: March 01, 2015, 05:54:18 PM »


Pete,

I'm entirely unclear on how the ant that you suggests works?
If I understand it, what you've done is to make the end of the antenna "fat"??

As opposed to looping the end back under the main wire and not connecting the end back to
the main wire.

                      _-_-bear

I guess you can call it end-fat dipole. Sort of a take-off on a fan or bow-tie dipole. I came up with this back in the early 70's when I was living on a much smaller lot and didn't have enough room for a full size 75 meter inverted vee. I have no recollection of any background info that made me try this design. It might have been one of those mental revelations that pop into your head when you're sitting in the quiet place. Fed it with coax and a coiled balun. I seem to remember without the tuner the antenna had the best SWR around 3940. The total dimensional length was based on the space I had. The 20 foot length per leg was purely a "pull from the air" guesstimate. 
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Pete, WA2CWA - "A Cluttered Desk is a Sign of Genius"
KX5JT
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John-O-Phonic


« Reply #27 on: March 01, 2015, 10:54:57 PM »

I've seen sites that mention something called "linear loading" for dipoles that do not quite have enough room.  I don't know how well the work but I thought I'd mention it.

Links and diagrams to follow...

http://www.m0pzt.com/?loadeddipole

http://w8mrc.com/docs/presentations/Shortening%20Your%20Dipole.pdf

http://www.af2cw.com/license/dipole.pdf

http://static.dxengineering.com/pdf/LL%20M-B%20Dipole.pdf


* linearloading.gif (6.06 KB, 327x295 - viewed 201 times.)
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Steve - K4HX
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« Reply #28 on: March 02, 2015, 06:56:07 PM »

Linear loading can work pretty well, especially considering it usually requires minimal effort. Capacitive end loading (dangling ends are a form of this) and inductive loading with high-Q coils is more efficient. This is where many have gone wrong for years, they used low-Q coils.
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W1RKW
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« Reply #29 on: March 03, 2015, 04:43:03 PM »

I had a similar situation at my previous QTH. But rather than have the 15 foot ends dangle down I simply "bent" them horizontally instead in opposite directions of each other, sort of a zig and zag about 100 to 110 degrees from the main run. I had no SWR issues and it was resonant and seemed to perform quite well.  Center was at 45 feet though.
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Bob
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Home of GORT. A buddy of mine named the 813 rig GORT.
His fear was when I turned it on for the first time life on earth would come to a stand still.
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