[GreenKeys] 88mH Toroides

[Harold Hallikainen]

> hmmm...  I'm starting to feel like the
> group peddler ... but I've been protecting
> all this stuff for decades -- time to start
> supplying you guys!!
>
> There's been discussion of 88mH toroids
> recently, so IF anyone is going to build the
> audio filters like we did back in the 50s and
> 60s, here's your chance with genuine, 'the
> real thing' toroids!
>
> I used to build, tune and sell mark and space
> filters back when I was in high school, and
> these are from then ...
>

Here's some stuff on the origin of those toroids:

http://bh.hallikainen.org/thg/monitor/Monitor_1919-05.pdf#page=37

http://bh.hallikainen.org/thg/monitor/Monitor_1926-04.pdf#page=17

http://bh.hallikainen.org/thg/monitor/Monitor_1924-11.pdf#page=16 wrapping
magnetic material around the wire to create a "loading coil"

Harold
https://w6iwi.org






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