[TowerTalk] Voltage Breakdown For Enameled Wire

Peter Voelpel dj7ww at t-online.de
Mon Jan 29 03:17:36 EST 2018

Use two pairs of Teflon covered wires in parallel.

Peter, DJ7WW

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim
Sent: Montag, 29. Januar 2018 03:03
To: towertalk reflector
Subject: [TowerTalk] Voltage Breakdown For Enameled Wire

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.


73, Jim K9YC


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