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 GQ320 Plus after Chornobyl trip - question
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mpmdembi

Poland
10 Posts

Posted - 05/15/2016 :  05:29:10  Show Profile  Reply with Quote
In Chornobyl I observed something strange on my GQ320 Plus
Near 4th block there was about 800CMP = a little more than 5uSv/h.
I have couple readings and as for M4011 tube proportion of 151.5 looks ok.
When i get closer to reactor and I have more than 1000CPM QG320 starts to show less in uSv/h - why?!
For exaple 1288CPM was 4.29uSv/h. Of course it was not only one reading. How more CPM can gives less uSv/h?
Reply #1

Distelzombie

Germany
141 Posts

Posted - 05/15/2016 :  08:52:16  Show Profile  Reply with Quote
Really. ZLM if you work for GQ you should start giving us answers to this behavior.

Same problem as in these threads:
- Found working Android App! (No CPM limitation)
- GMC-320PLUS display reading Problem

GMC-300E+ V4.20 with sbt-11 alpha tube

Edited by - Distelzombie on 05/15/2016 08:52:50
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Reply #2

Nisei

Netherlands
17 Posts

Posted - 07/02/2016 :  08:20:17  Show Profile  Reply with Quote
Have you been messing with the calibration settings?
It sounds like something's not correct there.
Go to the calibration settings and enter the default settings for Calibrate 1 through 3

John
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Reply #3

Distelzombie

Germany
141 Posts

Posted - 07/04/2016 :  06:24:42  Show Profile  Reply with Quote
That won't work. It's a bug.

GMC-300E+ V4.20 with sbt-11 alpha tube
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Reply #4

mpmdembi

Poland
10 Posts

Posted - 07/04/2016 :  12:17:41  Show Profile  Reply with Quote
I got new FV from support and now readings are correct.
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Reply #5

Hexalyse

France
2 Posts

Posted - 09/25/2016 :  04:47:39  Show Profile  Reply with Quote
What do you mean by "new FV" ? Are you talking about the firmware ?
Is it possible to update the GMC-320 Plus firmware ? Do they release updates with new features or bug fixes ?
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Reply #6

ZLM

1024 Posts

Posted - 09/29/2016 :  19:36:57  Show Profile  Reply with Quote
It is the calibration data problem.
Use following calibration data:

60 --> 0.39
240 ---> 1.56
1000 ---> 6.50

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Reply #7

mpmdembi

Poland
10 Posts

Posted - 10/16/2016 :  08:56:22  Show Profile  Reply with Quote
quote:
Originally posted by Hexalyse

What do you mean by "new FV" ? Are you talking about the firmware ?
Is it possible to update the GMC-320 Plus firmware ? Do they release updates with new features or bug fixes ?


Yes! New firmware with bug fixes. They promised new features, but till now, no new features :-(
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Reply #8

Distelzombie

Germany
141 Posts

Posted - 10/23/2016 :  03:35:06  Show Profile  Reply with Quote
quote:
Originally posted by mpmdembi

quote:
Originally posted by Hexalyse

What do you mean by "new FV" ? Are you talking about the firmware ?
Is it possible to update the GMC-320 Plus firmware ? Do they release updates with new features or bug fixes ?


Yes! New firmware with bug fixes. They promised new features, but till now, no new features :-(



Well... Swivel finally works on my 300+. It could be considered a new feature. XD

GMC-300E+ V4.20 with sbt-11 alpha tube

Edited by - Distelzombie on 10/23/2016 03:36:06
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Reply #9

cactus

France
3 Posts

Posted - 11/25/2016 :  23:02:20  Show Profile  Reply with Quote
Hello,

sorry for my english, I am french :-(

I have GMC-320+V4 Re 4.03

If CPM is superior at calibrate3 then µSv conversion is false (bug).

for M4011, using :
151 CPM = 1 µSv/h
1510 CPM = 10 µSv/h
32767 CPM = 217 µSv/h (too high possible and < 32768)

For test without tchernobyl, I use SBT-9 tube with alpha ray source Am241 (smoke detector).


Bye

------------------------------------------------
Bonjour,

Désolé pour mon anglais, je suis français :-(

Si la valeur en CPM est supérieure au calibre3, la conversion en µSv/h est faussé.
Pour corriger, il faut utiliser une valeur la plus élevée possible pour le calibre3, mais inférieure à 32768.

J'avais constaté le problème en utilisant un tube SBT-09 sensible au rayonnement alpha et une source issue d'un détecteur de fumée ionique en Am241. Avec la source au contact du tube, on arrive à obtenir des valeurs en CPM très élevées.
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Reply #10

cactus

France
3 Posts

Posted - 11/26/2016 :  02:40:32  Show Profile  Reply with Quote
To easily calibrate, i use software "GQ GMC Data Viewer"

- menu "Setting" / "Terminal"
- "Read From Unit"
- enter new calibrate
- "Write to Unit"
- powerOFF
- powerON

With "GQ GMC Data Viewer" software, it is possible to enter 65534 CPM for 434 µSv/h
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Reply #11

Suntse

Belgium
2 Posts

Posted - 01/27/2017 :  09:08:35  Show Profile  Reply with Quote
Hi cactus i'm french too (belgium)

y a t'il des soucis sur le gmc 320 + v4.2 la calibration que tu proposes résous un bug ? pour l'instant je n'ai rien remarquer je n'ai qu'une source une veille montre environ 320-340 cpm pour +- 2.3 ..., 2.4 µsv/h environ plus le chiffre exacte en tête j'avais compris que ça dépendais de la calibration de la source d'avance merci

sorry for the English community translation : Are there any problems on the gmc 320 + v4.2 the calibration you propose solved a bug ?The calibration depends on the source ?

GQ GMC-320+ v4.2 standard tube

Edited by - Suntse on 01/27/2017 09:12:59
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Reply #12

Distelzombie

Germany
141 Posts

Posted - 01/29/2017 :  15:05:00  Show Profile  Reply with Quote
For which isotope did you calibrate your device then? Am241 is mostly alpha radiator. The default tube can't measure alpha radiation. Therefore your calibration is wrong.

GMC-300E+ V4.20 with sbt-11 alpha tube
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Reply #13

ZLM

1024 Posts

Posted - 01/29/2017 :  15:05:42  Show Profile  Reply with Quote
The V4.20 is fine. No bug on calibration.
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Reply #14

Suntse

Belgium
2 Posts

Posted - 01/31/2017 :  06:43:34  Show Profile  Reply with Quote
thx :)

GQ GMC-320+ v4.2 standard tube
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Reply #15

cactus

France
3 Posts

Posted - 02/23/2017 :  00:24:11  Show Profile  Reply with Quote
quote:
Originally posted by Distelzombie

For which isotope did you calibrate your device then? Am241 is mostly alpha radiator. The default tube can't measure alpha radiation. Therefore your calibration is wrong.



Hello, sorry for my late answer.
I connected an STB-9 tube. This tube can measure alpha radiation.
Effectively. The conversion in #956;Sv/h of alpha rays is of no interest.
On the GMC-320 v4 + rev: 4.03, the calculation is false if the measured CPM value is higher than the value of calibration data 3.
Refer to mpmdembi's message.
Is not a calibration data problem.
This is a fireware bug that is fixed in the following versions.
My goal is to get a very high CPM value and check if the conversion in #956;Sv/h is correct.

désolé pour ma réponse tardive.
J'ai connecté un tube STB-9 qui est sensible aux rayonnements alpha.
Effectivement, la conversion en µSv/h de rayonnements alpha n'a pas d’intérêt.
Sur le GMC-320 v4+ rev:4.03, le calcul est faux si la valeur en CPM mesurée est plus élevé que la valeur du calibre 3.
Voir le message de mpmdembi.
Ce n'est pas une erreur de réglage du calibre.
C'est un bug du fireware qui est corrigé dans les versions suivantes.
Mon objectif est simplement d'obtenir une valeur en CPM très élevé et de vérifier si la conversion en µSv/h est correcte.
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Reply #16

Distelzombie

Germany
141 Posts

Posted - 02/23/2017 :  03:47:42  Show Profile  Reply with Quote
Hi cactus
Ups :)
I tested the new firmware (which is probably in the core the same) with my 300e and it's correct up to the maximum. (Maximum cpm is 65535.) Once they included a CPS mode we all will be more wiser.
What I don't understand: You know about the new firmware, why don't you email the support to get it?

Oh yeah, I also meant if you calibrate for Am241, your calibration will only be correct for this specific isotope. The ySv/h will be incorrect if you're measuring uranium or anything else.

EDIT: I could'nt find anything about this tube on the internet. Could you provide me with a link please? :)

GMC-300E+ V4.20 with sbt-11 alpha tube

Edited by - Distelzombie on 02/23/2017 06:46:28
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Reply #17

the_mike

Switzerland
2 Posts

Posted - 02/23/2017 :  12:34:49  Show Profile  Reply with Quote
Hi Distelzombie

pls. check following page:
sites.google.com/site/diygeigercounter/gm-tubes-supported
and
www.gstube.com/catalog/9/
(gstube for the datasheet)

there are good descirption for several different tubes... As for the SBT-9, they say:
"It was used in Russian space vehicles. A good poor mans substitute for the LND 712 if you're looking for an alpha tube. The SBT-9 seems to be about 50% as sensitive as the LDN-712 for beta and gamma, and about 35% as sensitive for alpha. (85 might be a good ratio for uSv to CPM if compared to the SBM-20 ratios) This tube and the STS-5 was used in Russian spacecraft."

Edited by - the_mike on 02/23/2017 12:42:17
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Reply #18

Distelzombie

Germany
141 Posts

Posted - 02/23/2017 :  19:51:14  Show Profile  Reply with Quote
Ok, thank you. :) I wonder why I or google couldn't find it even though I already know the page. :/

Has your question been resolved?

GMC-300E+ V4.20 with sbt-11 alpha tube
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