How do I wind a trifilar balun?

Hi Rich,

Ivan said it all, but the only additional comment I have is that for my transmitting baluns I use 1.5mm (cross-sectional area) multi-stranded insulated wire from power cable.

Multi-stranded wire gives you a much greater surface area, easier to work with, and you can use different colours to identify which winding is which.

It also gives a noticeable improvement at 28 MHz. I also use multi-stranded for my HF antennas for the same reason.

Nice to see you active on the forum

Very best regards from Harry - SM0VPO

Ivan,

Thank you. The pictures help a great deal.

- Rich

Hi Rich,
nobody is born with knowledge. Everybody must learn and it may be hard to find the prper info.
Do you mean the balun from here, picture no.3? "The transformer may be almost any ferrite ring for up to 50 watts or so"  A toroidal core ripped from an old PC PSU should IMHO do.
Twist three pieces of wire slightly and wind them together. Fill the core losely in one layer. Connect the wires according to the picture. Use a fairly thick wire, cca 0.5 - 0,7 mm, to reduce the skineffect.
Photos and specifications here may give you some inspiration.
Harry will probably give you more advice.

BR from Ivan OK1SIP

I expect buying it is wasting your money.

How do I wind a trifilar balun?

I want to build Harry's 20 meter small apartment loop. The design specifies a  trifilar balun. Apparently this is something every ham is born knowing how to do, but not I. I have dutifully Googled everything I could find, and have ended up more confused than when I started. How do I do this?

Type of ferrite? Dimensions?

How many turns? What size wire? Phasing?

If I decide to buy one, what is it called?

My only experience buying a balun turned out badly, because the Amateur Extra "Elmer" behind the counter turned out to have no idea what he was talking about.

Thanks.

Rich