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dbbyres
USA
8 Posts |
 Posted - 03/31/2012 : 15:56:51
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Hi, I got the GMC-080 kit and using SI-3BG tube bought on eBay.
Using my friend's sample, I get no noticeable CPM increase when the sample is close to the tube? Is this a problem with the SI-3BG tube, the kit, or should I be using a different, more sensitive GM tube?
What GM tube is recommended for this kit?
thanks,
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| Reply #1
ZLM
1261 Posts |
Posted - 03/31/2012 : 17:29:52
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The SI-3BG is a very low sensitivity tube. For the regular measurement, high sensitivity tube is needed.
The M4011 tube is one of the best tube on GMC-080. |
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| Reply #2
dbbyres
USA
8 Posts |
Posted - 04/06/2012 : 11:42:48
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Thanks. I ordered the 4011 tube from GQ Electronics on eBay. Arrived fast and easy to fit with the GMC-080 kit. Moderate soldering skills required.
Works great!
thanks,
David
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| Reply #3
NRFneversail
USA
22 Posts |
Posted - 04/15/2012 : 12:23:40
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quote:
Originally posted by dbbyres
Hi, I got the GMC-080 kit and using SI-3BG tube bought on eBay.
Using my friend's sample, I get no noticeable CPM increase when the sample is close to the tube? Is this a problem with the SI-3BG tube, the kit, or should I be using a different, more sensitive GM tube?
What GM tube is recommended for this kit?
thanks,
Recently, I also ordered the GMC-080. What I'm going to try with this unit is the Navy Victoreen Anton 6107 Alpha/Beta/Gamma tube. I'm unsure yet if I will mount it in the plastic case and penetrate the side to expose the Mylar window to the outside or build a hand probe housing and some sort of open-close window for it. I know the drawback on Alpha units is accidentally puncturing the Mylar windows. Sometimes, you don't even have to be able to see the hole(s)to have one that is ruined. As a former Rad Worker, I saw more than one DT-304 frisker probe get ruined but the ANPDR27R probes were pretty rugged as you had to really mess up to puncture one of those.
It has been a number of years ago I last dressed out in Yellows and used real Radiation survey instruments calibrated with radioactive sources but I think this may make for an inexpensive and fun CPM play toy. Will see when it all arrives as to what I may do with it.
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Edited by - NRFneversail on 04/15/2012 12:25:27 |
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| Reply #4
ZLM
1261 Posts |
Posted - 04/15/2012 : 21:13:39
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| Sure the 6107 tube will work. You juse need to set the voltage correctly. |
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| Reply #5
NRFneversail
USA
22 Posts |
Posted - 04/18/2012 : 18:10:25
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quote:
Originally posted by ZLM
Sure the 6107 tube will work. You juse need to set the voltage correctly.
I noticed in another part of the Forum, there was a picture of a GQ-080 with the 6107 Tube installed in the plastic case but looked like two large capacitors were added to the blue circut board.
I know on what little information is available on the 6107, it is recommended this Tube operate on 700-vdc but one ebay seller indicates they have ran them as low as greater than 300-vdc and were getting CPM rates I would consider normal for background. The GQ-080 I guess is capable of producing 200-550-vdc with a 5% tolerance.
What I would like to know is your experience with the 6107 Tube matched up with the GQ-080 and will it be adaquate to run this Tube or will I have to do a modification on this Geiger to up the volts or search for a different Alpha tube? I know you say it will work as long as the voltage is set correctly, maybe you can elaborate a bit more on this. Thanks and have a great day. |
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| Reply #6
ZLM
1261 Posts |
Posted - 04/18/2012 : 20:35:33
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The newer version GQ GMC-080 is able to produce more than 800V. So the voltage on GMC-080 is not a problem.
You do not need to modify anything on GMC-080 for your 6107 tube. Only need to turn the voltage.
If you use regular 11M ohm internal resistance on 1000V voltage meter, then you should be able to read the voltage on tube about 350V-400V when the real voltage about 700V.
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| Reply #7
NRFneversail
USA
22 Posts |
Posted - 04/22/2012 : 19:18:06
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Well, it seems I may have gotten a bad Tube. On start up, it did give a few distinct "Clicks" but then it did some continuous and intermentant static buzzing, also indicated by the LED light. I had to lower the voltage to reduce this but it did not stop it entirely. A couple of times, it even stopped registering any clicks and so had to turn the voltage back up only to have it make noise again. After about 3 hours, it would not register any more clicks at all and when turned off and then turned on, I got only the faint but also fading static buzzing till it seemed dead. I'm no Electronics super Tech. but it was my experience in my past work that a bad tube could react this way, some even produced an ear piercing squeal. I contacted the Seller I bought it from on e-bay and they are going above and beyond to make my purchase good. I know in the past, I've heard some bad about e-bay sellers and I have run in to a very few of them myself but this one selling the 6107, will without question, be at the very top of my list of Great Sellers. So, in a few days, I should have another 6107 Tube and will see if it works on my GQ-080. I know the Blue Board in my unit appears compared to other pictures Posted on this Geiger Forum, to possibly be the newer one and I did register the voltage you indicated. I know when the VR was turned all the way down at the beginning to get rid of the static buz, the tube still detected and the geiger made some clicks.
Maybe you have an idea of what may have happened and have suggestions.
Thanks much
quote:
Originally posted by ZLM
The newer version GQ GMC-080 is able to produce more than 800V. So the voltage on GMC-080 is not a problem.
You do not need to modify anything on GMC-080 for your 6107 tube. Only need to turn the voltage.
If you use regular 11M ohm internal resistance on 1000V voltage meter, then you should be able to read the voltage on tube about 350V-400V when the real voltage about 700V.
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| Reply #8
ZLM
1261 Posts |
Posted - 04/22/2012 : 21:42:18
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I think the tube is not a good tube for sure.
Anyway, it is good to tune the voltage always from low to high. And do not let the voltage exceed the tube voltage to high (+100V).
For safety, I will tune the voltage little lower(such as -30V). That will not affect the sensitivity on regular bases.
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Topic |
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Best tube to use with GMC-080?
