[Amps] Ferrite Core for 160M PI Output ?
Jim Thomson
jim.thom at telus.net
Tue Jun 13 05:41:59 EDT 2017
Date: Mon, 12 Jun 2017 15:44:33 -0700
From: Paul Baldock <paul at paulbaldock.com>
To: "Carl" <km1h at jeremy.qozzy.com>,<amps at contesting.com>
Subject: Re: [Amps] Ferrite Core for 160M PI Output ?
<I understand insulating between the wire and the core, but why do you
<need to insulate the two cores from each other?
## Extra reliability. If each core is wrapped 1st...then its wrapped 360 deg
around each core. If you instead wrap the entire mess of stacked cores, you
end up with air gaps here and there. Do both, and its bullet proof, with no
surprises.
## If you use polyimide wire..which I believe is the same as kapton.... for the
magnet wire, in the bigger gauges, its 15 kv rated. Like for 14-12-10-8 gauge.
## Then it becomes 30 kv between adjacent turns and 15+ between wire and cores.
But polyimide magnet wire is not cheap. But its bomb proof..and cheap insurance.
## If you really want to go crazy, you can also slide some teflon spaghetti tubing over the
polyimide wire. Array solutions uses that technique on some of its 9-1 un-uns and other applications.
## On a side note, If I remember correctly, the Ameritron amps used torroids on 160m..and maybe 80m as well.
They used a PI-L on 160m, and maybe 80m too..and def a PI on the other bands.
The idea was to be able to use a smaller load cap, and or less padding. I believe their was an issue when running
RTTY on 160m, or any other CCS data mode. The torroids cooked. If I remember the story, Ameritrons response
was they assumed no one would operate RTTY on 160m.
Jim VE7RF
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