522 9143 002 / FL118L-40
522 9139 002 / FL102L-40
Google search didn't do much
These things are HUGE too.
Pete
Designed for 118 and 102 kHz carrier frequency, 4.0 kHz bandwidth. These are asymmetrical, with extremely sharp selectivity slope on carrier side, and more gradual skirt selectivity on the opposite side of the passband. They were used for analogue voice/data multiplexing in landline circuits. The lowest frequency ones I have seen are at 64kHz carrier frequency. Good units for building old-buzzard style homebrew filter type slopbucket exciters. The steep selectivity on the carrier side allows good sideband suppression down to below 100~ audio frequency. Of course you need two conversions to get the VLF SSB signal up to the ham bands.
ESSB before the advent of DSP.
