[Elecraft] KX3 - 1:1 balun

[Don Wilhelm]

Steve,

Make, build, or buy a good 1:1 current balun.  Wind several turns of 
coax through the core and you have it.

Now, if you need an impedance transformer, you can make one from the 2nd 
core wind a primary and a secondary winding to obtain whatever impedance 
ratio you want.  connect the transformer primary to the output side of 
your 1:1 choke balun and the secondary side to your balanced feedline.

So the "wire" for your 1:1 balun is the coax, and the wire for the RF 
impedance transformer can be regular wire, insulated with enamel of some 
other material, it is not likely to matter.

73,
Don W3FPR

On 7/18/2012 7:13 PM, Steve KC8QVO wrote:
> I have a few Amidon T80-2 toroids and plan on making a 1:1 balun. I guess I
> really have 2 questions.
>
> 1. Would insulated wire work OK to wind it with or is it really necessary to
> use enamel coated magnet wire? I have some #28 or so (cuttings from computer
> ribbon wire) that may work out well (already bonded through the length of
> it, dual conductor parallel runs). If not I have some 18 gauge gold color
> magnet wire.
>
> 2. I am going to use a BNC connector for the rig side. I am thinking of
> putting a pigtail of LMR-100 (maybe 4-6") to the connector, but if it is
> going to be too lossy or cause the impedances to be too far out of whack I
> won't worry about it and make the balun a direct box off the side of the
> rig.
>
> My last question is if there are any good triple ratio balun designs. I want
> the 1:1 to match doublets, but a 2:1 and 4:1 ratio would allow a bit more
> flexibility in impedances.
>
> Steve, KC8QVO
>