The AM Forum

Admittedly, this isn't a piece of ham gear, but I thought I'd present it here to see of anyone recognizes this or knows what it does. I sent pictures to Ocean Research Equipment and they had no idea, but it appears to be part of a sensor or probe device given its circular circuit board and epoxy coating over all the components. The last image is a reverse-engineered schematic that I believe is accurate.

BTW, I didn't add the emitter arrow to the semiconductors although they are both likely NPN given the polarity of the electrolytics. The circuit was drawn so that the emitter leads are below the collectors.

Any guesses?

Clark,

Yep, I've seen one once before. A very rare find!  Obviously the company denies knowing what it is.

It's alien technology. Probably fell off an inter-galactic probe.  Put it on eBay and cash in big, OM.

T

cable TV Box.......

Tom is correct, but I think a more prudent course of action would be to remove the photograph and any reference to the "device"  If "they" (and I think we all know who they are...)  know you have it, things might not go well for you.  I am about to forget that I ever saw it.

Clark,

Looks like early 1970's assembly. That was over 40 year ago.  I looked up ORE and it is a 10 - 20 employee company today.  Odds are no one there then would be there today yet.

I guess the metal ORE can is the 3 pin box shown on your schematic.  I would be inclined to unsolder the can and put it on the workbench and see what frequency response you get through it.  Sweep from audio to 100 kHz.  Drive one side with a blocking cap from a function generator, less than 100 mV out, hang a scope on the other pin.

It was used to monitor/identify undersea alien arrivals and departures off the northern coast line of Long Island so as not to interfere with existing domestic and international air traffic.

Looks like one of them D-104 adapter rigs for an early rice box...

Yeah, definitely unsolder that can and desolder the seal on it (or is it epoxy filled?) and see what is inside!

I was surprised by the swift denial of any knowledge of this device by that company. I thought they'd be even slightly interested because their name is on it.

So the consensus is that it's an underwater alien homing beacon? Are your addresses all good on QRZ?

You are correct, Clark.

I would contact this gentleman as soon as possible.

T

It may be a component from a towed marine sensor system called a 'streamer'. These are usually for geophysical research such as investigating the ocean floor or its subsurface for a variety of reasons, and include acoustic and geomagnetic sensors among other alien technologies from the 1970's.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0706212 is interesting.

I agree with the filter test suggestion. be sure to include subsonic and ultrasonic frequencies in the test.

Great reading, thanks! This looks like a good lead toward figuring this out.

It appears that terminal "2" is both the supply voltage input and signal output, so I put a 68k resistor in series with a 12V supply and connected a scope to the terminal. Next I added a low level 1kc sinewave signal to the terminal marked "IN" but saw no output even when the frequency was swept from 10c to 100kc.

It turned out that terminal "1" requires a bias voltage (the circuit doesn't seem to provide for this). The cleanest waveform with highest output was achieved when this terminal was fed +3.4V. A new frequency sweep showed a sharp peak in output at 7.8kc, so it seems that the "mystery box" is a very narrow bandpass filter.

Also of note, I could see some bright flashing lights in the sky but my attention was focused on the suddenly functioning circuit. Even more strange was all the sideband-like activity that suddenly appeared in the AM window. Removing the bias quieted everything down again.

Now you've done it.  You've released classified information to forum readers.  Men in black will be paying you a visit shortly. 

What to do with a 7.8KC bandpass filter? Creatively, what uses?

After a bit of research, I believe this was most likely used for:

Echolocation of false killer whales in the Antarctic

"Two types of killer whale echolocation clicks were recorded, with peak frequencies at 7.8 and 19.5 kHz, durations of 186 and 68us, and inter-pulse intervals (IPIs) of 4 and 800 ms, respectively."

"Whistles recorded during one sighting had simple structure, short duration and a mean fundamental frequency of 7.8 kHz. The descriptive parameters of 20 false killer whale whistles recorded during Sighting 4 indicated a mean fundamental frequency of 7.8 kHz."

So there you go. I've never heard of "false killer whales" before (http://en.wikipedia.org/wiki/False_killer_whale (http://en.wikipedia.org/wiki/False_killer_whale)). Who would name them that? Aliens? That's like a boy named Sue. Now I need to make some kind of plausible connection to amateur radio in order to justify this post...