Your choice of MPP is very unorthodox.
MPP = moly permalloy powder.
Generally, ferrite is used for baluns.
It is also used for some tuned circuits but
powered iron has some advantages for tuned
circuits and is often used in that
application. I've never seen MPP used
for RF. Can you tell us why you
chose MPP? How is it different or similar
to "powdered iron"?
73
Rick N6RK
On 10/27/2014 10:37 PM, Paul wrote:
Hi Guys,
Getting ready to put up my KT-34XA this weekend and just trying to get the
balun right. I have been experimenting this week with cores and windings and
have found a combo that sure looks good on the MFJ-259 and seems to not get
too hot on a soak test...what I have come up with is a core from Arnolds MPP
series which is 125u, 2" diameter and with 8 turns 14ga enamel with
Fiberglas tape spacers, bifilar wound for each half ,on one core, I am flat
from 1MHz-45MHz with the MFJ-259. Running 500W through it for 5 minutes gets
it hot, but I can still hold it. I want to end up winding it on 2 cores,
half on each and am wondering if I should use the same # of turns on each
core as I would if it were a single core, ie 8 turns on each core, then
connect to make it a 4:1, or do I need to modify the turns count when I
split to 2 cores? Also, when splitting to 2 cores, do they need to be
oriented in any particular way or can I stack them one on top of the other,
like 2 doughnuts? The antenna is all rebuilt and tested with my single core
balun....just need some + temps and no snow for the weekend.
Your advice is greatly appreciated.
73
Paul
VE7KHz
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