| T O P I C R E V I E W |
| mrdwm1 |
Posted - 03/10/2014 : 11:56:38
I've just discovered GQ and am interested in the 320, but have some dumb questions. My use for this unit would be "hobby", occasional use around home and central Calif. beaches. Guess I'd like to know how long I should expect this unit to work before tube replacement or other maintenance. Also, how can I calibrate or otherwise verify it's performance? Is there a better place to ask questions like this? Thanks in advance for any advice. |
| 5 L A T E S T R E P L I E S (Newest First) |
| ZLM |
Posted - 03/24/2014 : 14:31:59
check your iPhone settings. Especially on input sensitivities. |
| jump-ball |
Posted - 03/19/2014 : 08:31:52
...EXP goes.from it's normal bkg - background - of 50... |
| jump-ball |
Posted - 03/19/2014 : 08:26:35
My 200 reads 20 background everywhere in desert cities CA but jumps to 1000 CPM on my attached iPhone on 4 separate visits to my cardiologist's waiting room where there are 3 large 'AC vents' on the ceiling, but yesterday I took an Inspector EXP which only went from it's big of 50 to 300 CPM. Can anyone tell me what radiation the M4011 gmc-200 tube would be more sensitive to than the tube and 2 inch mica wand of the EXP? The EXP readings on a thorium check source disk, on the hepa filter, on my Vaseline glass and on my Metlox Poppy Trail pink serving plate (8000 CPM!) are all 5 to 12 times higher |
| ZLM |
Posted - 03/11/2014 : 22:07:28
The Geiger tube output the electronic pulses when it detects radiation. Normally the tube can output about 100 Million pulses during its life time. |
| bifferidge |
Posted - 03/11/2014 : 17:40:24
I honestly don't know much but I can tell you that both my GM200 and 300 needed new tubes within 1yr. That was an easy fix putting in cheap russian tubes on ebay. I am not sure but I hear rattling in the tubes so I am wondering if I do not treat them gently enough.
As you mention- it is a HOBBYIST machine, NOT for first responders or radiation workers.
Regarding calibration - I did not calibrate (sounds a bit complicated as i guess i would need a reliable source) - however both my GMs seem to run approximately the same as my Berkley Radionics handheld (which is calibrated yearly under contract) and my fun Polimaster wristwatch.
Not sure what you're hoping to find along the beaches, but good luck! |
