Dear Fellow TowerTalkers,
Trying to make a hybrid coupler (collins method) for 2 phased verticals.
Found a recipe in ON4UN's Low Band Handbook.
And what seemed an easy calculation, regarding the number of turns, is
keeping me puzzled.
The used componets : 1 Amidon T225 core a a piece of copper wire.
The inductance should be 1.13uH for 7 mc/s.
Formula L= 50/ 2*3.14*7.05
According to the formula for calculating the number of turns, in my case
for 7 mc/s, it turned out to
9,7 turns making 10 turns.
Formula N = 100 * square root 1.13 / 120
10 turns on the T225 core gave 2,50 uH in stead of the desired 1.13 uH.
Measured with my MFJ259B.
I don't expect the MFJ very accurate, but 100 % off, I don't believe.
So where am I going wrong?
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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