CHOKE  VS  BALUN

The only difference between a

1:1 Guanella Choke

and a

1:1 Guanella Balun
is the connector(s)

on one side.

HOW TO WIND A CHOKE

Honestly, this is the simplest thing to build in the entire world!  As seen in the picture on the right, simply wind the coax around a toroid core and the choke itself is finished.  All that remains is to add the connectors.

Tip:  If using a PL-259, it is best to solder one onto the end of the coax before winding.  Do not solder both because this makes winding through the small hole difficult.  Once the choke is finished, soldere the other connector(s).

Looking at this particular choke, how many turns of coax pass through the inside hole?   ANSWER:  17.

Even though the first and last piece of coax passing through the hole do not make a full loop, they still count as a full turn.

When we speak of turns on a core, we really mean "number of passes through the hole."

W1JR  WINDING  METHOD

Joe Reisert, W1JR designed a method to cross-wind the turns of wire or coax onto a toroid core.  Notice how the coax winds in one direction (bottom center, upwards towards the right), then crosses back over to the bottom center, then winding upwards and left. Although this looks totally different than the simple single-direction shown in the picture above, electrically it is exactly identical.  OK, in my example, this choke has one more turn than the one above, but other than that, they are exactly the same for the purpose of choking common mode current.

The cross-over also counts as one turn (in this case turn 10) because it passes through the hole.

THE REASON for using the Reisert method is, for mechanical reasons,  sometimes we want to two ends of the coax to exit opposite sides of the toroid core.  Notice how one exits down, the other up with this method, whereas in the standard method (above) both ends of the coax exit to the bottom.

THAT IS THE ONLY SIGNIFICANT DIFFERENCE! 

USE WHICHEVER HAPPENS TO WORK BEST FOR YOU.