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 Station ID: 1:8AE3A67B.4 - Montrose, Colorado, USA 
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Joined: Wed Jun 20, 2018 1:22 pm
Posts: 6
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I have repositioned my "GMC 600 Plus, Tube:LND-7317" geiger counter from where the sensor was vertical and 12 inches from a wall ... TO ... now horizontally facing down about 1-inch above a wooden surface (a TV dinner stand). Additionally, I have indirectly placed a 6-inch personal-fan at about a 4-foot distance in order to keep the air moving near/around the geiger counter.

I did this for a couple of reasons ...

1. sensor now facing down to reduce any dust that might collect on the geiger sensor.
2. added a very-light constant-air-movement around the geiger counter for a better consistency/accuracy.

After doing the above, I notice the CPMs jumped about 10 to 15 counts higher ... and ... I thought NetC and its Members should know since these counts now appear noticeably different.

Farley
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Sun Jul 01, 2018 3:36 pm
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Joined: Mon Jan 28, 2013 7:40 pm
Posts: 2885
Location: Illinois
Thank you for the update and your continued dedication to being a part of the NETC private monitoring network. It is greatly appreciated by many.

_________________
MY OUTSIDE RADIATION MONITORING STATION:
South Beloit, Illinois - GMC200 Outside on HEPA air purifier, ground level, facing West.
http://netc.com/chart/view.php?n=1%3AEB5A139C


Mon Jul 02, 2018 9:23 am
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Joined: Wed Jun 20, 2018 1:22 pm
Posts: 6
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I'm using the "GMC 600 Plus" containing an LND-7317 geiger tube.

The factory-conversion-factor for uSv = (CPM / 380) ... and ... nSv = (CPM / 0.38) ... (for making Japan comparisons).

I noticed that my GMC is reporting near 4-times more radiation exposure than the units located/reporting in Tokyo ... ( i.e. Tokyo 35 nSv/h compared to my average 60 CPM, 0.16 uSv/h, 158 nSv/h :shock: ).

I have a 2nd "GMC 600 Plus" with an LND-7317 tube positioned identically and 2-feet from the 1st GMC ... I'm getting very similar CPM readings between the two.

Am I converting and reading this correctly ???
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Mon Jul 02, 2018 1:02 pm
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Joined: Wed Jun 20, 2018 1:22 pm
Posts: 6
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As a continuation/follow-up of my previous post ... Both of my "GMC 600 Plus" Units containing LND-7317 Geiger-Tubes are within 2-feet of each other at my location in Montrose, Colorado, USA.

I plan to run/record my "Unregistered 'Comparative'" unit occasionally to verify the readings from my "Registered" unit.

Unregistered 'Comparative' "GMC 600 Plus" - Station ID: 1:4CE9F404.9
http://www.netc.com/chart/view.php?n=1:4CE9F404.9

Registered "GMC 600 Plus" - Station ID: 1:8AE3A67B.4 - Montrose, Colorado, USA
http://www.netc.com/chart/view.php?n=1:8AE3A67B.4
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Tue Jul 03, 2018 10:53 am
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Joined: Wed Jun 20, 2018 1:22 pm
Posts: 6
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GQ provided me with a "GMC 600 Plus" Firmware-Update relating to CPM-Pulse-Data through the Data-Port thereby eliminating the need for the Audio-Port and Audio-Cable if/when desired. In My Opinion, this is a much, much more accurate way of obtaining CPM-Pulses ... After the Update, I needed to restart/reboot both "GMC 600 Plus" units.

( i.e. both GMC displays now perfectly match the window of NetC's software at the end of each minute! ) :D

I did not stop the NetC data-collection and upon reboot of the units, an unexpected data transmission occurred creating an 8800-ish CPM data-spike to both of my NetC datasets ... so I chose to Delete both of my NetC-datasets.

Both of my "GMC 600 Plus" Units containing LND-7317 Geiger-Tubes are now within 6-inches of each other, horizontally facing down, 2-inches above a heavy-plastic folding table, and with and indirectly-pointed 6-inch personal-fan 2-feet away to guarantee air-flow around both units at my location in Montrose, Colorado, USA.

Farley
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Sun Jul 15, 2018 2:25 pm
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