Although not a performance issue, the clear Nylon coating of THHN does not
hold up well to UV. I typically see it splitting after 1-2 years of being
exposed to the sun.
Paul, W9AC
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of
john@kk9a.com
Sent: Friday, January 3, 2020 3:20 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 80M antenna wire size
Of course you do not need to use bare 14 awg wire, THHN (available in at
least ten different colors) works well for antennas and in that size 500'
rolls are very inexpensive. Your 20 awg PTFE is 40% smaller than the 14 awg
THHN. If they were both the same color would the size change be enough
visual difference to justify the PTFE's extra cost along with its
compromised wire strength and antenna efficiency?
John KK9A
tony n2tk wrote:
Jim,
Tnx for the input. On a sunny day the shiny copper really stands out even
after all these years. I had bought a bucket (around 80 lbs) of enameled
copper from a transformer company years ago.
The 5 radials at each feedpoint are 57'. I tie them together through a coil
to the coax shield. I tap the coil with a relay so I can easily switch the
minimum dumped power at 3525 and 3750. Shortening the 1/4 wave radials to
57' sure improved the pattern. Much better F/B and F/S since I did that.
This could be a nice winter project.
73,
N2TK, Tony
-----Original Message-----
From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Jim Brown
Sent: Thursday, January 2, 2020 11:19 PM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] 80M antenna wire size
Teflon insulated wire, especially the silver-coated stranded copper I've
found on the internet to wind chokes, is VERY nice stuff. And it's
expensive.
Sometimes it can be quite worthwhile to make antennas less visible, and
reduced weight can be an advantage in some situations, but those are the
only good reason I can think for doing that way. There are times I've
suggested enameled wire for low visibility. As noted, insulation will lower
the resonance slightly, and although larger conductor diameters can increase
SWR bandwidth, that's hardly a critical factor, it's likely to be too little
to notice for the relatively small change from #14 to #20.
73, Jim K9YC
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