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Author Topic: Has anyone tried a parallel dipole with wires not parallel?  (Read 769 times)
N8TI
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Posts: 115




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« on: February 25, 2012, 08:41:02 PM »

Hello. I have a lot of telephone cable  that has four or five wires twisted together. I imagine making a multi band dipole out such wire would be hard to tune on the separate bands, but I wondered if anyone ever tried it.

Joe N8TI
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WA9YSD
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Posts: 138




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« Reply #1 on: February 25, 2012, 08:52:02 PM »

The old two conductor parallel conductor could be used as open line.  Very lossy cause of the rubber, I cannot remember, it is ether 300 or 72 ohms.  If you want to play, make into a fan dipole. Scroll down to find it.  http://www.amateur-radio-wiki.net/index.php?title=Dipole#Fan_Dipole

Leave about 3 feet of wire on each end for each band hang down.   Have fun.

Jim K9TF
« Last Edit: February 25, 2012, 09:07:25 PM by WA9YSD » Logged
WB6BYU
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Posts: 13457




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« Reply #2 on: February 25, 2012, 09:39:06 PM »

I used 10-conductor ribbon cable, which is pretty closely coupled.  But rather than cutting
each wire for one band I cut them as staggered lengths on 80m.  With some creativity I was
able to get the SWR below 1.5 : 1 across the whole range from 3.5 to 4 MHz.

For multi-band use I'd recommend letting the ends hang down from the rest of the bundle
for a couple feet or so - that will reduce the tuning interaction somewhat.

Also the outer insulation on the cable often provides a significant amount of the tensile
strength, so you'll want that as intact as possible when tying the insulators on the ends if
you are going to put much strain on it.  That probably means slitting the sheath and pulling
out the wires, trimming them, then slipping the remaining wires back inside.
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N4JTE
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Posts: 1158




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« Reply #3 on: February 26, 2012, 03:04:29 PM »

Here is article I wrote awhile back, might be helpful. http://www.eham.net/articles/21407
It was composed of ribbon wire from model train supply and was a lot of fun and cheap.
Little sweat equity needed on these type of antennas but worth the effort.
Bob
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