The worst Geiger-Müller Counter I have Ever Bought! The model G16 😶

Seriously! This thing is garbage! It actually doesn't work either, no surprise.

I bought this on eBay a couple of years back and just never got around to posting about it. I paid just £16 for it plus about £4 postage. It was cheap, super cheap. I didn't expect a lot, but I didn't expect to find what I did. After plugging in it's USB C connector and getting a little charge into it, I turned it on. It powered up and displayed 0.09 µSv/h on the display. Then after a short while it dropped to 0.00 µSv/h. I placed a source by it and nothing. I tried a stronger source, still nothing. So I took it apart.

First off, the case. It's awful. It is the kind of cheap feeling flimsy plastic you expect to get from a toy out of a Christmas cracker. Poor mouldings, the buttons are sloppy, it kind of moves about and creaks in your hand. It is a press friction fit with just one retaining screw at the bottom end. It's generally just really poor, or made to a very low price. Probably the latter.

Now onto it's innards. First of all the tube looks strange, and the battery too. Both very strange forms. The tube is just a straight glass tube, with very square edged end-caps and wires soldered onto the end-caps. Looking at the tube I can't see the usual glass seals around the anode, and seemingly there is no cathode either, that I can see. On most other glass tubes you can see the difference on the glass where the tin oxide layer is, and there is usually a wire with some epoxy or similar fixing.

This tube looked like the anode was connected to both end caps so I grabbed my meter, set it to the ohms setting and clipped it onto the tube wires, after cutting the negative from the board. Exactly as it looked like - the tube is physically shorted by the anode. Except that isn't an anode, and this isn't a Geiger-Müller tube either. It's a piece of wire, connected to each end-cap running through a glass sleeve. It's a giant fuse! 🤣 So that would explain why the count started at 0.09 (fast warmup type thing) then dropped to 0.00 and wouldn't budge from there. There is no GM tube. It's a scam, a fake, a fraudulent GM tube! This is the first and only time I have ever received a not a tube in a counter. I have received some questionable tubes, but they have worked as a GM tube should.

Then the battery. Interesting. Is it a super-cap? It looks like one, but doesn't bear the markings of one. 10300 is a battery size and AliExpress does sell some similar batteries, therefore, it must be a battery. 3.7 volts nominal, probably Li-ion or a LiPo cylinder. 0.22wh doesn't sound a lot, and no, it's not. This battery is 60mAh (3.7v * 0.06 Ah = 0.222 wh). 60 mAh, just 60. Not 600, or 6000, just 60. It might last an hour on a full charge. Though I never tried to see how long it would last. I never tried another tube in it either.

The board isn't very exciting either. It has a basic HV PSU, a sounder, some dodgy no-brand MCU hiding under the sticky pad that holds everything together, and some BMS/charging circuitry, that I don't know if I would trust.

Finally the front of this miserable excuse for a counter. Nothing much to say. It has a screen. It has three buttons and a couple of other bits, and that is about it. Very much the worst counter I have ever bought.

Not all was lost though. I did contact the seller with my findings and some photos and explained about the tube not being a tube, and the battery having about enough capacity to run the thing for 30 seconds, and that I generally thought I was being scammed. The seller quickly refunded the full amount. So I get to keep this POS, and write about it, for free. My advice is if you see one of these model G16 counters on your travels, carry on walking, or browsing, or whatever you are doing, just don't buy one.

This counter deservedly gets my 100% Scamtastic badge!