Re: Binocular choke extras

On Thu, 20 Mar 2025 12:39:43 -0400, legg <legg@nospam.magma.ca> wrote:

On Wed, 19 Mar 2025 23:24:36 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:
>

On 3/19/25 22:40, Liz Tuddenham wrote:

I've just taken delivery of a couple of ferrite 'binocular' choke cores;
each one came with two thinwalled metal tubes and some bits of printed
circuit board.  The tubes appear to go through the holes in the choke
and the holes in the boards fit over the ends of the tubes, with copper
areas that could possibly be soldered to them.
 
Does anyone know what purpose these serve?
 
 

>
This sounds very much like the transformers used in wideband RF
power amplifiers. See for example Helge Granberg's application
note 762. The tubes with a piece of circuit board form the single-
turn low impedance winding, and a number of turns of insulated
copper wire going through the tubes form the high-impedance
winding. This makes for a good coupling factor and consequently
good wideband operation.
>
<https://www.communication-concepts.com/content/AN762/AN762_Application_Note.pdf>
>
Jeroen Belleman

>
Can also be used in directional couplers and baluns, which I suppose
are just high frequency transformers by another name.
>
RL

Some people enjoy calling txline transformers "ununs" when neither end
is a balanced load against ground.

Is there a balbal?