[Elecraft] BL-1 Cores

[Charles Greene]

Mike,

Actually you can do it with one core.  Impedance is ~ N^2 where N is the 
number of pairs.  2 pair, 4:1, 4 pairs, 16:1.  Wind 2 pairs on each side 
together, then it's just a matter of wiring them up.  Wire all on each side 
in series, connect start 1 left to start 1 right.  Input goes to end 1 left 
and end 1 right.  Output goes from end 4 right to end 4 left.

At 12:26 PM 10/18/2003, Michael Fitzgerald wrote:
>Does anyone know where the BL-1balun cores come from?  I want to try two 
>in series to make a 16:1 to feed a TTFD type broad band folded dipole.  It 
>seems to me the binocular core is working as two completely independent 
>choke type current baluns, paralleled on one side and in series on the 
>other and there is no sort of flux coupling or transformer action going 
>on.  I wonder if the outer jacket on the bell wire is the secret to its 
>performance by holding the twisted pairs a little bit away from the 
>core.  I would have thought CAT-5 would be good since it's a very 
>precisely made 100 ohm transmission line.  TNX MF

73, Chas,  W1CG
K2 462b, 3571