VLF to HF Converter Box, 5 Channel WJ TFC-212, Nice parts!

Description

Here is a box made by Watkins Johnson for telephone intercept work, type TFC-212. It has 5 nice converter boards in it that upconvert the VLF range to HF frequencies using a crystal controlled oscillator. Each board has a WJ/Relcom M6 double balanced mixer on it that covers from below 100 KHz to 300 MHz and these are easily removed if you so desire (5 mixers total). The boards unplug (25 pin card edge connectors) and the mating socket is easily removed. The wiring is super simple to figure out by inspection.  The chassis has a power supply, all needed switching etc, some nice parts here!  The power supply provides 25 V unregulated for the lamps in the switches and 18 VDC for the converters. The transformer is 24-0-24 Volt (48 V Center tapped for full wave rectifier at 24 V) rated at 250 mA, realy nice small sealed transformer!  The unit is in good physical condition and I am selling it for parts as I do not think too many people are interested in demuxing FDM (but if you are, I have a whole 960 channel system for it 12 channels by 5 group by 16 supergroups...).  Have fun!