NETC.com :: View topic - Station ID 1:EBEB8CE7 Lawrence, KS, US

Kyle_G wrote:

Ok I powered off the geiger counter and unplugged it from the PI. I had a count of 319 when I unplugged it. I turned it back on unplugged from the Pi and after a couple minutes I'm getting a reading of 365.....and after a couple more minutes it is reading 326 cpm.

Zehd wrote:

This is not a software glitch--the GMC-300E is legitimately reporting those high CPM readings to the pi4netc software.

It looks like either he has a radiation source that came in, or there's something wrong with the geiger counter. There have been a few isolated cases of these geiger counters messing up like this, usually issues with the battery or battery charger circuit.

First recomendation would be to replace the battery (at least temporarily) with a standard alkaline 9-volt battery. You will have to use a phillips screwdriver to remove the two screws on the back, and there is a jumper you will have to move (right next to the battery) that toggles the charging circuit.

KingCobra wrote:

I thought those problems were only noticed with the GMC-200 not the GMC-300 models.

Am I wrong?

Kyle_G wrote:

Ok ...I've installed a new alkaline battery. I had a count of about 249 when I turned it off and now few minutes it is up over 300 cpm but I'm in my computer room that has bigger windows.

Will it hurt the non-rechargeable battery to be plugged into the PI raspberry since that tries to recharge the battery?

Author:	KingCobra [ Fri Dec 13, 2013 3:40 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
I highly doubt the radiation is that high so I think your unit might be defective but let some of the ADMIN ask you a few questions.

Author:	Kyle_G [ Fri Dec 13, 2013 3:44 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
Ok I powered off the geiger counter and unplugged it from the PI. I had a count of 319 when I unplugged it. I turned it back on unplugged from the Pi and after a couple minutes I'm getting a reading of 365.....and after a couple more minutes it is reading 326 cpm.

Author:	Zehd [ Fri Dec 13, 2013 3:50 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
This is not a software glitch--the GMC-300E is legitimately reporting those high CPM readings to the pi4netc software. It looks like either he has a radiation source that came in, or there's something wrong with the geiger counter. There have been a few isolated cases of these geiger counters messing up like this, usually issues with the battery or battery charger circuit. First recomendation would be to replace the battery (at least temporarily) with a standard alkaline 9-volt battery. You will have to use a phillips screwdriver to remove the two screws on the back, and there is a jumper you will have to move (right next to the battery) that toggles the charging circuit.

Author:	KingCobra [ Fri Dec 13, 2013 3:52 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
Kyle_G wrote: Ok I powered off the geiger counter and unplugged it from the PI. I had a count of 319 when I unplugged it. I turned it back on unplugged from the Pi and after a couple minutes I'm getting a reading of 365.....and after a couple more minutes it is reading 326 cpm. This is a good example of where a 2nd geiger counter is always a good idea so a failure in the detector can be ruled out ASAP. Having a GMC-300 much like yours, the radiation would need to be very high to get readings like what you are saying from the air. Sounds like something is wrong with your detector.

Author:	KingCobra [ Fri Dec 13, 2013 3:55 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
Zehd wrote: This is not a software glitch--the GMC-300E is legitimately reporting those high CPM readings to the pi4netc software. It looks like either he has a radiation source that came in, or there's something wrong with the geiger counter. There have been a few isolated cases of these geiger counters messing up like this, usually issues with the battery or battery charger circuit. First recomendation would be to replace the battery (at least temporarily) with a standard alkaline 9-volt battery. You will have to use a phillips screwdriver to remove the two screws on the back, and there is a jumper you will have to move (right next to the battery) that toggles the charging circuit. I thought those problems were only noticed with some of the GMC-200 not the GMC-300 models. Am I wrong?

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Author:	Zehd [ Fri Dec 13, 2013 4:05 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
Here's the charger-enable jumper I was talking about: Attachment: File comment: GMC-300E Charge Enable Jumper gmc300-charge-enable-jumper.jpg [ 233.41 KiB \| Viewed 49415 times ] (we strongly recommend you turn your unit off before opening it, don't do like we did in the picture. That GM tube is charged to very high voltage when on) KingCobra wrote: I thought those problems were only noticed with the GMC-200 not the GMC-300 models. Am I wrong? You're partially right: we've only seen this issue with the GMC-200 units so far, but the GMC-300 uses the exact same gm tube, same battery, and quite possibly the same charging circuit as the GMC-200 (We'd have to ask GQElectronics to make sure), so it's quite possibly the same issue.

Author:	KingCobra [ Fri Dec 13, 2013 4:05 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
If the spike would have happened sometime other than 4am and if this unit was in an apartment, their is a chance that a neighbor had some radioactive testing done. I guess if this unit is in an apartment, there still is a chance that some late night radioactive testing (stress test) was done on a neighbor and then released to go home. In which case, the reading might be real and the decline shown in detection is the decay rate happening within the neighbor/patient.

Author:	Kyle_G [ Fri Dec 13, 2013 4:15 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
Ok ...I've installed a new alkaline battery. I had a count of about 249 when I turned it off and now few minutes it is up over 300 cpm but I'm in my computer room that has bigger windows.

Author:	KingCobra [ Fri Dec 13, 2013 4:19 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
Kyle_G wrote: Ok ...I've installed a new alkaline battery. I had a count of about 249 when I turned it off and now few minutes it is up over 300 cpm but I'm in my computer room that has bigger windows. Will it hurt the non-rechargeable battery to be plugged into the PI raspberry since that tries to recharge the battery? Yes it will hurt the non-rechargeable battery, if you do not adjust the jumper correctly. The jumper shown in the above picture will disable the charging of the battery. If you are not sure of how to adjust the jumper, just make sure you do not plug in the geiger counter to the USB or your non-rechargeable battery might explode or leak.

Author:	KingCobra [ Fri Dec 13, 2013 4:22 pm ]
Post subject:	Re: Station ID 1:EBEB8CE7 Lawrence, KS, US
If a neighbor having a radioactive stress test is a possibility, you should be able to leave your house/appartment and see the CPM drop as you get further away from the source. Please see more information on the radioactive stress test with video example here: https://www.netc.com/bb/viewtopic.php?f=7&t=401

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