Closer inspection - they're not EXACT duplicates - minor circuit
modifications one way or the other, but they both work on the same
principle. Comments below still apply.
Norm
W6NIM
On 11/19/2012 11:37 PM, Norm wrote:
>
> There is nothing magic about this circuit! It is a duplicate of the one
> in ∗_QST_∗, December, 1969 pg. 11, or the 1970 ∗_Radio Amateur's
> Handbook_∗, pp. 557-558 - which also gives the calibration procedure.
> I've built several of these over the years - used just any ferrite
> toroid core available that would pass the co-ax through the center -
> you're going to have to calibrate it anyway. Any trimmer cap will work
> - ceramic, mica or air dielectric - just keep it small and use the
> shortest possible leads. Diodes? 1N34 from Radio Shack will work - in
> fact they're called for in the reference articles. If you can't find
> the feedthru caps, pass a wire through a hole in the shielding, and
> bypass on the side away from the RF section. The only reason to
> slavishly follow the pictures is if you are doing a restoration for
> complete authenticity. Put the works inside a box that resembles the
> original, and who (besides yourself) will know the difference?
>
> The magazine or book should be available from larger libraries - maybe
> on eBay - or from members of your local radio club. If you are
> desperate, contact me off-list and I'll e-mail you the two pages.
>
> Norm
> W6NIM
>
> [Non-text portions of this message have been removed]
>
>
>
> No virus found in this message.
> Checked by AVG - www.avg.com <http://www.avg.com>
> Version: 2012.0.2221 / Virus Database: 2629/5406 - Release Date: 11/19/12
>
[Non-text portions of this message have been removed]