Google found an ad for it in the April 1978 (!) issue of Ham Radio Magazine.
http://mirror.thelifeofkenneth.com/lib/ham_radio_magazine/Ham%20Radio%20Maga...
See page 94. It looks like it's intended for listening to Mode J on a Mode A receiver, so down-converting 435MHz to 29MHz. This would be for the "new" Oscar 8 satellite. :-)
Martin. KD6YAM
On Thu, Apr 18, 2019 at 4:07 PM David Fine via AMSAT-BB amsat-bb@amsat.org wrote:
I'm looking for information (possibly a schematic) for a Lunar Electronics Oscarbox J that I picked up from an estate sale. I'm not sure exactly what it is and haven't been able to find any information on it. Looks like it might be a 432-436 mHz converter? Any help please? Dave, W0DF _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb