[Elecraft] BL-1 and BL1-1 Balun Questions

[David F. Reed]

Ron,

thanks very much for the clear explanation; that was exactly what I was 
doing; I can get 2 visible turns around the outside just fine, and you 
explanation of the phasing making the ratio makes sense to me.

Again, many thanks.

--Dave--

Ron D'Eau Claire wrote:

>Hi David:
>
>You asked about how to get the three turns on the BL-1 core. Three turns
>means that you see TWO loops of cable going down the outside to of the core
>on each side. (Remember, turns are *always* counted by the number of passes
>through the center of the core). For each hole, the wire starts at one end
>of the core, goes through the hole (that's turn 1), loops around the
>outside, back through the same hole (turn 2), around the outside the second
>(and last time) then goes back through the same hole (turn 3) one last time.
>Where it starts at one end you'll strip and solder to the terminals on the
>board near the coaxial input connector and where it ends at the opposite end
>you'll strip and solder the wires to the terminals at the output end of the
>BL1 board. 
>
>I have a hunch you're trying to see three loops of wire around the core on
>the outside: that's why it won't fit and there isn't enough wire. That would
>make four turns! 
>
>You wanted to know if you were building the 1:1 or 4:1 version. The ONLY
>difference between them is how the windings are connected at the output end
>of the board. If you hook the red and white leads to the circuit board pads
>as shown on the board - white leads to white pads and red leads to red pads,
>you'll have a 4:1 balun.
>
>If you want a 1:1 balun, connect the two white leads together and connect
>them to the pad marked WHITE nearest the edge with a number 2 on the board,
>then connect the two red leads together and connect them to the pad marked
>RED at the edge with the number 1 on the board. The inner "white" and "red"
>pads are not used. That's the only difference between the 1:1 and 4:1
>versions.
>
>Ron AC7AC
>  
>
-- 
David F. Reed  - W5SV -     cell: 512 585-1057