[palegreenthumb]

I'm curious whether anyone knows anything about the availability of aftermarket accessories like Beat Frequency Oscillators (BFOs) for Philco radios? Were they factory options? Available from Philco through the dealers? Entirely 3rd-party? A competitor's product? Homebrew?

I recently purchased the Philco 16B pictured below, which was originally owned by a ham (I am 4th owner). The previous two owners sold it along without restoring it, but both believed that the object sitting on top of the power transformer with the extra tube is a BFO. Yes, that's right, a 12-tube 16B. The tube type is a 37.

I haven't dug into it yet to see what makes it tick. It's connected to the under-chassis by a harness of cloth wire with 5 or 6 conductors. But I'm curious to know whether anyone is familiar with something like this?

Thanks!

[Chuck Schwark]

Don't believe so, since Joe Homeowner or Grampa would not know what it was or how to tune in SSB signals. Not many on the air then in any event.
Copying CW was also not in vogue then either for the home listener.

Chuck

[Phlogiston]

I have had a couple of radios come in where people had tried to add a BFO. At this point I can't remember which ones they were. But, the addition was "home made".

[Radioroslyn]

I would suspect that it would be a HB job. Back in the day the only thing you would have used it for would have been CW. SSB wasn't developed till the mid 1950's and not popular till the mid to late 1960's Defiantly a cutting edge technology in the '50s and mostly done/built by hams that where in to experimental design. Actually if you need a quick and dirty BFO it's pretty easy to run a small length of wire attached to the grid cap of the IF amp then a few quick turns around the glass portion of the tube till it oscillates.
Terry

[palegreenthumb]

Huh, I kinda thought it seemed at lesat manufactured in a factory. Note the presence of a screw hole at the right rear corner that doesn't match up to anything in this installation.

When I tear into it, be that a week, month, or year from now, I will dig up the thread and post more details. Maybe I'll find a maker's marks or something.

Anybody ever see a magazine ad for an after-market BFO?

[exray]

I don't know about the Philco 16 but some models from RCA (such as the 140) and GE (such as the A-82) had an 'optional' BFO available. These two in particular were marketed to hams and you see the ads in QST of the era. May have been done as a dealer upgrade.