[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!