[GreenKeys] Polar Relays

[Harold Hallikainen]

On Thu, July 11, 2024 11:24 am, B. Smith wrote:
> It seems that Polar Relays are becoming popular again. Info and a test
> jig can be found:
> http://k4che.com/Polar%20Relay%20Test/Polar%20Relay%20Testing.htm
> K4CHE

Their use in terminal units is interesting. I think they were generally
used as analog comparators with hysteresis (comparing the magnitude of the
mark and space tones and keying the loop with the result). The TU I built
in high school using 88 mH loading coils used a 12AX7 as a differential
amplifier which then drove a 6L6 keying the loop.

Harold
https://w6iwi.org



-- 
Not sent from an iPhone.

-- 
Not sent from an iPhone.