Use two pairs of Teflon covered wires in parallel.
73
Peter, DJ7WW
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim
Brown
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.
Suggestions?
73, Jim K9YC
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