| T O P I C R E V I E W |
| Senketsu |
Posted - 01/29/2021 : 06:03:24
I decided to check if the factory voltage settings of the Geiger counter would handle higher radiation levels :)
For this I used a Sr90 control source with a power of about 1 R / h (1000 uSv/h)
By bringing the source closer to the active surface, M4011 began to drastically lower the result.
In my experience, setting the voltage to 46% is not enough...
while the voltage change to 50% allows you to easily measure up to 1000 uSv/h :) Maybe it's worth changing this value in the next update?
My 500 and 500+ use Re 2.25 |
| 20 L A T E S T R E P L I E S (Newest First) |
| Senketsu |
Posted - 04/29/2022 : 14:55:19
Refresh my old topic. I bought five new GMC-500. These are the latest versions from Re 2.29. They No have problem described above, they have an automatic HV. In older versions, I suggest setting the voltage for the GM meter to 50% (it works perfectly for me) |
| EmfDev |
Posted - 03/02/2021 : 16:48:26
You can check by opening the battery cover and by checking voltage reading. |
| cvee |
Posted - 03/02/2021 : 16:11:20
Its all sorted.
Reached out to GQ through Amazon and they got back to me.
It should be the latest.
Also got a direct email from GQ following this thread.... so sorted.
My new (first) geiger is coming tomorrow.
Do i need to open the unit to check the hardware version... or is there a menu setting that shows it? - i guess i'll find out soon enough. |
| cvee |
Posted - 03/01/2021 : 15:50:02
quote:
Originally posted by EmfDev
Hi cvee, last hardware update was more than a year ago. If you buy this time it will be the latest hardware.
The listing is very specific in referencing 2017 which is why I was put off ordering. The Amazon US listing doesn’t reference a year… it just says the latest model.
That’s why I am concerned.
https://www.amazon.com.au/gp/product/B071JWB7TJ/
If I’m buying it now.. I want to be sure it’s the latest version pcb 5.2
|
| EmfDev |
Posted - 03/01/2021 : 11:13:38
Hi cvee, last hardware update was more than a year ago. If you buy this time it will be the latest hardware. |
| cvee |
Posted - 03/01/2021 : 01:56:53
“it seems like your hardware does not support the Auto Adjust HV. In that case it is better to manually increase the voltage to 50%.”
When was there a hardware revision for the 500+ ?
How can I know if it includes the auto voltage function before buying?
The Amazon listing states :-
Year 2017 model, dual geiger tubes sensor, independent calibration factors
Will this have the hardware fix or is there newer revision/version available? |
| Senketsu |
Posted - 02/04/2021 : 04:41:48
You're right, I only see 46% in both versions, while the GMC-600 also has a value in volts. Thanks |
| EmfDev |
Posted - 02/03/2021 : 16:41:55
@Senketsu, You can check the tube voltage from the Main Menu -> Init Setup -> Tube Settings -> Tube 1 voltage. If you see something like
"40% (400V" on the popup, then it can do the Auto Adjust Voltage. But if you only see "40%", then it does not support the feature. |
| Senketsu |
Posted - 02/03/2021 : 12:56:30
@EmfDev, I think it's a problem with Re 2.25, the problem is with my GMC-500 and 500 Plus, Can you check it?
@ullix,Thanks for your help, you may be right but it looks like this problem can be solved with a fix in the software |
| EmfDev |
Posted - 02/01/2021 : 11:27:09
Hi Senketsu it seems like your hardware does not support the Auto Adjust HV. In that case it is better to manually increase the voltage to 50%. |
| ullix |
Posted - 01/31/2021 : 06:12:29
@Senketsu:
Chances are the effect is due to the High Anode voltage collapsing. This has been discussed at length and enriched with many experiments in this topic: http://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=5369
In Reply#17 it begins to get hot!
Beginning in Reply#31 the collapsing voltage comes into play.
Wikipedia https://en.wikipedia.org/wiki/Geiger%E2%80%93M%C3%BCller_tube has this helpful graph:
Briefly, when you start in the middle of the plateau, and then increase count rate, the voltage drops more and more and you move to the left end. With enough radioactive events to go past the left end, you have no electric pulses anymore and therefore no counts. When you increase the voltage, you move the starting point to the right, and thus have a bit more leeway for higher counts until it also goes past the left edge.
Supposedly in some GQ firmware versions the counter increases its voltage settings to extend this measurement range. I am not aware of any tests on this feature.
|
| Damien68 |
Posted - 01/31/2021 : 05:55:57
quote:
Originally posted by Senketsu
Hi @Damien68, thanks! I will try to record a video in text mode.
This problem does not occur on the GMC-600 with SBT-11 (Tested up to 1200 uSv/h)
I know that on the 600+ the HV generator is twice as powerful, on the 600 I don't know, the default setting may be different too.
on your video we see a clear difference between 46 and 50%, it smells like the HV generator which weakens too much.
But don't expose yoursef to much. |
| Senketsu |
Posted - 01/31/2021 : 05:13:06
Hi @Damien68, thanks! I will try to record a video in text mode.
This problem does not occur on the GMC-600 with SBT-11 (Tested up to 1200 uSv/h) |
| Damien68 |
Posted - 01/31/2021 : 05:05:01
Hi Senketsu, nice video.
in tube setting menu, you have "High voltage display" option just after "Tube 1 & 2 voltage" option
this show in real time the effective tube voltage (require the display to be in text mode).
this can be interesting to see variation of it with default setting and in high CPM condition.
.
|
| Senketsu |
Posted - 01/31/2021 : 04:31:11
My video shows the measurement of the radiation source with factory settings, then I increase the voltage to 50%, please look this
https://youtu.be/EYJAxBERp64 |
| Senketsu |
Posted - 01/30/2021 : 04:00:48
The problem is that the factory settings of the GMC-500 and 500+ (Re 2.25) are not able to measure a source with a power of about 1000 uSv/h (approaching the radiation source close, the dosimeter even stops working!) However, when I manually set the voltage to 50%, the problem does not occur.
The specification data shows the range of 4250 and 42500 uSv/h (500 and 500+).
The device with the factory settings does not function as specified :/ |
| Senketsu |
Posted - 01/29/2021 : 19:14:48
Hmm, thanks for information, so I will try to record a movie what the problem occurs when the voltage is factory set (when I make changes in the options, the problem disappears) |
| EmfDev |
Posted - 01/29/2021 : 13:24:07
You do not need to set it, it is included in the firmware. If your device can read the internal voltage (e.g. 46%(490V)) it means that your hardware supports the automatic voltage adjustment. If it does not show the voltage, it does not support the feature. |
| Senketsu |
Posted - 01/29/2021 : 12:37:31
Thanks for your answer, can you tell me how to set auto voltage change?
Currently, I do not see any other solution how to permanently increase the voltage so that the GMC-500 and 500+ do not stop at high radiation levels.
I can also make a video showing it in practice
I will appreciate your help in setting up the automatic voltage change |
| EmfDev |
Posted - 01/29/2021 : 11:31:24
Hi Senketsu, the sensors might not work correctly if the voltage are out of the working range. And there is an automatic high voltage adjust feature that increases the voltage automatically when the voltage becomes lower as a result of high CPM/radiation. |
