Topband: [Bulk] Re: 160 GP Choke

[Guy Olinger K2AV]

I like to wind these kinds of things using RG400. That's RG58-sized teflon
dielectric and teflon jacket with silvered copper double shield and
silvered copper fine wire stranded center conductor. RG400 is specifically
made to be put in airplane wiring harnesses with all those sharp bends and
corners, and never melt or catch fire or have the center conductor migrate
through the dielectric.  And it will easily handle QRO power with CCS duty
cycle. Designed to be reliable after you've spent the good money to bundle
and install it in something very expensive, and never ever need replacing.

You can solder good PL259 connectors with the correct UG175 adapters, no
worry about melting anything.  Do the math, get the right number of turns
on the right count of the right kind of core and forget it.  Damp will not
make it go bad, silver oxide is conductive. Make one of them this way and
you have a permanent device that you get to keep.  You're done.

Small lengths of RG400 for this kind of work are inexpensive on eBay,
either by ordering a cut length or getting surplus jumpers with misc
connectors which I just cut off flush.

You can get the winding length needed by winding RG58 on the core(s) for
the required turns to make a precision buy of the RG400. Just remember to
add what you need for the PL259 and connecting lengths.

73, Guy

On Tue, Sep 30, 2014 at 12:36 PM, Tim Shoppa <tshoppa at gmail.com> wrote:

> The 0.75" #75 clamp-on is 0475176451 and circa $15. By my connibulations
> it'll be a really close squeeze to get 5 turns of RG-6 through there. I
> think 5 turns of RG-58 could happen.
>
> The 2.4" #31 core is 2631803802, circa $7 and much easier to get many more
> turns of RG-8X through it.
>
> Tim N3QE
>
> On Tue, Sep 30, 2014 at 9:28 AM, Grant Saviers <grants2 at pacbell.net>
> wrote:
>
> > Jim,
> >
> > Would the type 75 material from Fair-Rite, be a better choice for 160 &
> 80
> > with 5 turns thru the 0.75" id clamp on?
> >
> > http://www.fair-rite.com/newfair/LowFreqSuppression.html
> >
> > your thoughts?
> >
> > Grant KZ1W
> >
> >
> > On 9/29/2014 11:56 AM, Jim Brown wrote:
> >
> >> On Mon,9/29/2014 10:43 AM, wb6rse1 at mac.com wrote:
> >>
> >>> Bill -  An effective common-mode choke can be made with 17 turns of
> >>> RG58-coax wound on to an Amidon FT240-31 core.
> >>>
> >>
> >> It's not an Amidon core, it's a Fair-Rite core. It's a LOT cheaper when
> >> you buy from a Fair-Rite distributor. See Appendix One of
> >> k9yc.com/RFI-Ham.pdf
> >>
> >> 73, Jim K9YC
> >>
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