Here's one of those old things you just pick up because it's old.
It is a "portable test oscillator". That much is no mystery, but that's abo ut it.
So I dig up a 90 volt power supply, actually by taking an old amp carcass a nd connecting between the positive and negative rails. A variac got it to t he level I wanted. It oscillates, but really doesn't put out anything. I sh ould have put the frequency counter on it but the bench was full up.
V402 is putting out a sine wave. As you can see by the print though, it doe sn't go anywhere without some sort of input because V401 is normally in ful l conduction. On the left is a device they call E402. It appears to be some sort of a cap and waveguide or something like that. I am not taking it apa rt if I can help it.
The input on the left marker "2" seems like it might accomplish a little bi t of frequency modulation, for whatever reason. The input marked "3" would seem to result in amplitude modulation.
It's not a huge mystery how the thing works, but I am puzzled as to its act ual purpose. Is it for testing recievers out in the battlefield or somethin g ? Like puts out a steady tone for everyone to tune to with their reciever s, something like that ?
I'll probably get some pictures of the whole thing soon in case anyone migh t recognize it that way. I never thought to take them, I just got one of th e schematic which is glued to the inside of the cabinet.