Yeah I was contemplating that, Joe.
I had noticed balundesigns had a new balun (25:50) that does that idea
with a smaller core..picture here
http://www.balundesigns.com/servlet/the-92/1-cln-2-unun-25-ohms/Detail
although I just ordered a bunch of 4x4x2 carlon boxes.
the local home depot/lowes both only had the crappy Cantex version,
which has thicker walls (bad for so-239 mount) and a crummy lid (no
recessed gasket)
In terms of series combinations: I read where someone tried it (two
cores close) and didn't like the results..he wondered if the close
proximity of series cores might have some coupling?
-kevin
On 5/31/2010 5:19 PM, Joe Subich, W4TV wrote:
>
>
> > By using 18 awg, I can space the bifilar turns to get some separation
> > turn to turn to help increase voltage breakdown between turns.. and I
> > won't use the full toroid..So I won't do a crossover winding, but
> > still be able to get to the SO-239's on either side of the 4x4x2
> > NEMA6 box without too much distance or extra capacitance.
>
> Instead of mounting the toriod stack flat in a 4x4x2 box, why not
> mount it "on end" in a deeper (e.g. 4x4x4 or 4x4x6) box? It might
> take a little creativity to build a mounting baffle but standing
> the toroid stack "on end" would allow it to be mounted very close
> to the output side of the box and minimize the a amount of the
> windings in proximity to any metal mounting plate or boom.
>
> "On edge" mounting might also fit well with a rectangular box
> for baluns with a larger number of cores - or series combination
> of cores for wide band applications.
>
> 73,
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