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Old 3rd Dec 2021, 4:02 pm   #42
Techman
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Join Date: Nov 2009
Location: Lincolnshire, UK.
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Default Re: Unidentified bits of test gear

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Originally Posted by Techman View Post
Regarding the previously shown piece of homebrew kit as mentioned and shown in posts #30 and #35.
So it turns out it's an alien detector!

I applied 9 volts and it puts out pulses of around 160KHz a little faster than once a second. It's a dirty old waveform, but seeing as I was taking it from the transformer secondary output it'll be this that's distorting the waveform, as it wouldn't be very happy at this frequency.

I can't say for certain that it came off this particular unit, but I found a bit of paper on the bench where I've had this thing and scribbled on it are the words "contact crop circles". This bit of paper has definitely dropped off one of these bits of kit that I've been playing with and I do remember seeing this label on something, but just not sure if it was on this or not. I don't know much about crop circles, other than the late Reg Presley from 60s band The Troggs was heavily into them, but perhaps the croc clips were to be connected onto metal stakes inserted into the ground to be picked up by some sort of receiver - just a thought.

There has to be an article on this thing in an old Practical Wireless magazine or similar you would have thought.

The question is, does it have any use today? I note that there are some useful parts, particularly (for me) the cosmetic centres of the terminals to replace the missing ones on the Wayne Kerr bridge - and 'Gridiron' (previous post), that certainly is an early serial number on yours. It seems that there are a few of these units about, but very few actually being used.

Below is the pulse waveform - you wouldn't believe how many snaps I had to take to capture that fraction of a second pulse (I got about three in the end and that one was the best...this is perhaps where a storage scope would have been useful:-
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