| T O P I C R E V I E W |
| bc10 |
Posted - 08/14/2019 : 12:02:45
New owner of a GMC 600+ here.
I don't have a standardized source to test the accuracy of the device's measurements right now. I'm wondering what your CPM per uSv/hr conversion is?
Mine is roughly set at 350 CPM per uSv/h.
Is that the default setting? Are each unit individually calibrated at the factory or do they use the same conversion for the same model? Is this conversion factor in line with other products that also use the LND 7317 detector?
My current background radiation is reading roughly 50 CPM indoors. Seems kinda high in activity but it could be OK if the detector is more sensitive.
Also, are any of you guys using makeshift methods to protect the exposed detector when you're not attempting to measure alpha? In case dust settles on the detector's surface. I'm currently using some 3M painters tape to cover up the opening. |
| 9 L A T E S T R E P L I E S (Newest First) |
| Stargazer 40 |
Posted - 08/14/2019 : 18:28:56
The LND spec sheet for the 7317 shows 350CPM/uSv for the specified recommended voltage. GMC may be running a little hotter than that for GM tube voltage so 330 might give a better match for some counters. I'll stay with 350 for my 600+. It's also what Mazur uses in the 9000 meter.
I'll be running some new calibration tests and posting results shortly. Waiting on some firmware upgrades. Some really exciting things going on with GQ stability as counts go high. Should once again take GQ up another big notch for their flagship meter. |
| paul |
Posted - 08/14/2019 : 13:58:42
and it would be very nice and a bit more ergonomic if there were such
an option.
would make it easier to see ,as each tube seems to have a different
conversion rate. |
| EmfDev |
Posted - 08/14/2019 : 13:33:05
Oh that's true. It only shows CPM when you don't click on the pins. And option to change it to dose isn't there. |
| bc10 |
Posted - 08/14/2019 : 13:29:31
quote:
Originally posted by EmfDev
The pins also display the uSv/h beside the CPM in the map.
The pins in my web browser only seem to show the raw CPM number. Some pins show uSv/h but I'd have to click on a pin to see it. |
| EmfDev |
Posted - 08/14/2019 : 13:00:25
The pins also display the uSv/h beside the CPM in the map. |
| bc10 |
Posted - 08/14/2019 : 12:54:42
quote:
Originally posted by EmfDev
You can check this thread by stargazer 40
https://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=5554
Thanks! That's very interesting raw data. His device is also around 350 conversion for the LND 7317.
This leads me to wonder if there is a setting for GMCmaps to show converted dose measurements instead of raw CPM data? Most people don't have the more sensitive models when uploading their readings to the crowd sourced map so can't compare apples to apples with people in my area. |
| EmfDev |
Posted - 08/14/2019 : 12:41:50
You can check this thread by stargazer 40
https://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=5554 |
| bc10 |
Posted - 08/14/2019 : 12:34:45
quote:
Originally posted by Geo-Johnny
quote:
Originally posted by bc10
Mine is roughly set at 350 CPM per uSv/h.
Conversation 350 could be okay.
Look at this: https://sites.google.com/site/diygeigercounter/technical/gm-tubes-supported
Thanks. Yeah I was just taking a look at that blog too. It seems the Inspector EXP that also uses the LND 7317 uses 330 conversion factor according to the author. |
| Geo-Johnny |
Posted - 08/14/2019 : 12:27:36
quote:
Originally posted by bc10
Mine is roughly set at 350 CPM per uSv/h.
Conversation 350 could be okay.
Look at this: https://sites.google.com/site/diygeigercounter/technical/gm-tubes-supported |
