I just wound an ameritron look alike with #28. It's larger than they use. I
have an original ameritron choke to compare with. I think they must use #29.
My resistance was lower using #28 and it was less uH.
73
Jim W7RY
On Sat, Jan 16, 2010 at 6:59 PM, Jim Thomson <Jim.thom@telus.net> wrote:
> I Checked a bunch of really old e-mail, and notes. The folk's who
> duplicated the KK5DR plate choke, using 1/2" type 43 rod, stuffed into the
> inside of a hollowed out 1" OD Teflon rod
> had nothing but grief. All the rods overheated ! In some cases, the
> rod actually launched itself out the top !
>
> Either 1" type 43 rod is required, [like several type 43, 1" Od
> beads slid over the 1/2" rod].... or several type 43 rods bundled
> together.
>
> Perhaps type 43 material is the wrong stuff to be using for a plate
> choke...esp considering the typ plate load Z's involved ??
>
> Type 43.... 1" OD bead's, slid over 393 Teflon coax makes for
> excellent Choke baluns. The 1/2" x 8" long type 43 rods work great
> for Bifilar's. But in both those cases,
> the Z is only 25-50 ohms.
>
> What would be an excellent solution, would be a higher current version of
> the RF parts /Ameritron plate choke. I have asked a few times what ga
> wire is used in the Ameritron choke,
> and can't get a straight answer. I believe it's around 28 ga. A
> version made with 22 ga wire would be the ultimate solution. I know how
> Tom designed the Ameritron choke.
> However, I'm not prepared to sit there in the shop for months, with a
> vna, etc, trying to park resonances. The 2 x choke + relay version
> was a cheap way to get around the problem.
> Incidentally, the choke relay coil was activated by a 3rd wafer on the
> tuned input switch.
>
> Later.... Jim VE7RF
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