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Re: [TowerTalk] Voltage Breakdown For Enameled Wire

To: jim@audiosystemsgroup.com
Subject: Re: [TowerTalk] Voltage Breakdown For Enameled Wire
From: John Simmons <jasimmons@pinewooddata.com>
Date: Sun, 28 Jan 2018 20:35:37 -0600
List-post: <mailto:towertalk@contesting.com>
Have you thought of using a 1:1 balun of the guanella type? I built mine using RG400 and one core. No signs of problems at the legal limit and 2:1 SWR.

-John NI0K

Jim Brown <mailto:jim@audiosystemsgroup.com>
Sunday, January 28, 2018 8:02 PM
I'm once again considering winding high power chokes with enameled wire. Zo of a closely #12 pair is about 53 ohms, which makes it desirable IF breakdown voltage is sufficient. I would appreciate for sources of #10 or #12 enameled wire with published breakdown specs.

I've found that THHN (about 93 ohms Zo) works fine for simple antennas like dipoles, but some multiband antennas with complex matching/coupling systems don't like that much mismatch. We had this problem with the Force 12 C3SS, the choke is enameled #12 of unknown pedigree. No breakdown issues with a 600W power amp and the antenna is a good match to it, but the engineer in me wants to be conservative for legal limit to an 80/75 dipole that I use from 3.5-3.9 MHz.

Yes, I know I could put the conductors in Teflon tubing, but that increases Zo. I've measured #12 pairs with various Teflon insulation and get values around 101 ohms at HF.

Suggestions?

73, Jim K9YC


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