Unfortunately, I don't have a 2N2907 in my junkbox, but I do have a LOT of 2N3904 and 2N3906 transistors, so I'm trying to alter the circuit to accommodate these devices. Guess I'll have to go read the tutorials again! God - how I hate being old and forgetful! LOL. I have most of it already input into LTSpice, but it's been so long since I've used the program that I've forgotten how to setup the AC voltage source and frequency.

I might even be able to do a simple swap-out of the transistors and give that a shot (for the heck of it), but I'm thinking I'd be much better off using LTSpice and design the thing properly. The PTO provides 400-500 KHz of bandwidth, and I'm hoping that, properly designed, I can keep the diode turned on enough to actually hear stuff decently. What I'm trying to do is see how well I can make a minimal-parts-count receiver play.

I'm also thinking about adding an RF amplifier to the front end, just to see how she plays. I do have schottky diodes to roll my own passive, doubly-balanced mixer, though I'd like to experiment a bit to see how well I can get the diode detector/mixer to work.

It's also important to point out that I'm trying to use a 1N34A diode as a mixer. Well, this is kind of a somewhat unique application, so, first and foremost, let me provide a link to a schematic: If it is a matter of voltage, and not dBm power, just use a broadband transformer wound on a ferrite core.

Free download 2n3906