Re: Binocular choke extras

Glen Walpert wrote:

Don wrote:

Glen Walpert wrote:

Don wrote:

>
<snip>
>

It looks to me that the 3 sections of coax shield are in parallel with
the metal tubes and their opposite end shorting bar, forming the low
impedance single turn winding, to be connected at the unshorted end
with the coax shield connections, hi-Z connections to coax center
conductors extending from opposite end - 4:1 balun?

>
<https://www.qsl.net/kf8od/ldmos1.html> offers a more fleshed out
circuit description. The designer designates the device a 4:1 "very
broadband transformer."
    <https://www.qsl.net/kf8od/ldmos34.jpg> shows the schematic. In the
amp as assembled, the transformer output's oriented on the bottom:
<https://www.qsl.net/kf8od/ldmos50.jpg>. Everything about its output
makes perfect sense to me. The transformer's twin tubular primary inputs
shown at the latter link also makes perfect sense to me.
    A center tap for the transformer's the thing missing from my mind's
eye. Perhaps the shield of the coax cryptically connects the center tap?

>
Thanks, that clarifies things.  A bit tough to see in the assembly photo,
but the center tap on the single turn primary is the shorting bar between
the two metal tubes on the same end as the coax inner conductor
connections.  I suppose the two 1/2 turn primary windings contribute
independently to the 4 turn output to provide the stated 1:16 ratio.

My earlier spiel contains a typo. Its last link should be
<https://www.qsl.net/kf8od/ldmos40.jpg>
    One of KF8OD's captions says "the coax is used to accomplish a close
coupling" - presumably to enhance efficiency and performance. It's
apparently OK for the coax shield to bypass the center tap and act as an
ancillary primary.

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.