@@blackfox_357chief4 When I made this video, it was summer here in the tropical region of China and the humidity was consistently over 85%, once winder arrived I found that without the loading resistor, the PSU voltage peaked pretty high and caused some ionization in the tube. It should also be noted that as part of an crowd-science experiment I am currently running, it seems that there is a lot of manufacturing variability in the PSU voltage of the GC-01.
I've watched a handful of your videos now, and want to thank you for the work that you put into them. In this one, you researched the company and also the white-box situation with this product. You did a thorough review and identified not only its shortcomings, but why. And as a bonus, how you worked around them. Your work is really over the top. And the post-production graphics and editing are really nice. Again, thank you.
I bought FNIRSI GC-01 on Amazon (Sold by "FINRSI Technology"). Production date on the box is listed as 2024.06.01. I opened it immediately and I am happy to report it came with M4011 tube.
I bought this p.o.s. and I dont know why I didn't look for video reviews first. Well, after being very disappointed by my purchase, I found this video, and it's making me feel so much better. I was worried that I was doing something wrong, but now all my suspicions are confirmed, and I've gotten to laugh a bit too! Lovely video!
Hi, I bought my FNIRSI GC-01 ne week ago via Amazon. I opend it up right away, and found a J321 tube in it. The date of production on the box is 2023-07-11 I gues I was lucky 😊 I totally like your suggestions to optimise this product. Thanks for this amaising reviev 👌🥰
Have the j321 tube came in a box dated may 2023 The boxes have dates of manufacture on the side Be easy to ask a seller when it was made It seems these earlier ones are 👍
I was really upset with mine. It was advertised with a big tube and the one i got was tiny. It couldn’t detect americium or soft xrays. I was irritated considerably
I ordered mine in december 2022 from TomTop and paid 39,59€ ( arround $43) after seeing the review done by IMSAI Guy. I didn't know there were (or are) 2 types of tubes for this meter. I just checked, and mine has the J321 tube. Thanks for sharing this information. Grtz
This was very helpful and insightful. I saw this on Amazon and figured “what a great price”, but with all things cheap, you get what you pay for. I was wanting to know if this was worth the $70 on Amazon and thanks to you, you saved me from spending my hard earned money. I’m sure there is better out there that I’m not afraid to throw extra money into it, provided that it is a good product. Much appreciated
Congratulations on the excellent videos! After changing the GM tube the measured level (background too) flew into the sky. Fortunately, your new video about the firmware upgrade helped to fix the error. With your help, this GM counter has been a good, cheap instrument. THX!
I bought the branded FNIRSI GC-01 back in 2022 and luckily it has the J321 tube and it works perfectly in line with with my old USA cold war CDV-777. when using the check source they both match to my suprise.
I sold my Pudibei NR1050 and bought the Bosean FS5000. It came with the J321 tube. I agree that it is a well-made device. The FS5000 can be upgraded with Radpro open-source firmware (as can the Fnirsi GC-01) and is then compatible with GeigerLog v1.5 PC software for logging, data transfer and analysis.
I have this FNIRSI GC-01, purchased around August/2023 and I can confirm they changed the tube for an even WORSE Version than the J631, the new one is half the size around 50mm long only. After watching your video, I ordered a J321 and will make this mod. thank you very much for the video! Edit: I've just found the model installed it's a J613.
Wow excellent review and upgrade , I have this unit and had no idea as to its inadequacies. I just took mine apart and confirmed I still have the J321 tube in mine. I must have old stock. The other caveat is there is a fastening screw underneath the small black label on the back that would’ve been nice if you had shown that has to be removed it’s hidden under the plastic black label peel it off and there’s a screw under there to remove. I know you know that but watching the video I don’t think anybody else knew that but thanks again for your great analysis of this product. Cheers.😊
I really appreciate the feedback, thank you! Perhaps the mechanical design has been updated in the version that I have, but I didn't need to remove that label to get the unit apart, as you can see in the tear down, there is no hole in the middle of the PCB to accommodate a 5th screw post. Just the 4 corner screws were removed and mine came apart. I looked at some other YT reviews with tear-down's and this was also the same (if you find any different, please post a link here). I have been asked to do a quick video to clarify the details of how I added the particle sounds, so I will be sure to include a part about this aspect, so you can see this on my version of the device. I have also had an extensive email exchange with the FNIRSI and their B2B commercial sales team confirmed that the factory that makes the branded products also manufacturers the unbranded ones (which is usually the case here in China) and FNIRSI even helps with this sales process and I assume they even earn a commissions as the white label versions are sold through their B2B team.
@@ralger I'm pretty confident that if there is a design change, it will have efected all of the versions. When did you get yours? FNIRSI confirmed that the change to the new tube was pretty recent. The sales guy said they changed over to the new GM tube（几个月前）which translates to a number of months ago (between 1 and 4, there is a different expression for numbers between 5 and 10).
@@ralger I just released an update for those wanting more info about how to add the particle clicks and I made a special effort to show the absence of the additional screw on my unit. Please take a look and let me know your feedback! It would be really strange if the tooling for this as changed, that is a very expensive change to make. When they changed to the new $hitty GM tube, they didn't even bother to update the PCB but just did some hand mods. Updating the PCB is pretty cheap in comparison!
Hi, thank you for your review and these valuable information and insight! I bought this device about a year ago. It has the J321 tube in it I remember it because I was once in a hurry and dropped it and it stopped measuring. When I opened it, mine had no glue at the place of the tube so the tube moved after it hit the ground and lost contact. I moved the tube back in place and it works again. However Its a shame they have changed the manufacturing process, its misleading the customers.
4:24 the battery inside is just a standard 3.7v lithium cell, so really any lithium cell you can fit in there should work just fine to improve its capacity
I bought one. It had a cracked tube. They moved to a different tube design (one with wires and soldered leads like you mentioned in the video) that is just taped down at a weird angle so it fits inside the housing. Since mine had a cracked it worked even worse than the one you tested, as in not at all. I think you're 100% correct in your analysis.
Why is no one talking about how this absolute unit of a man if HANDLING RADIOACTIVE MATERIALS WITH HIS BARE FUCKING HANDS. Amazingly informative video but my guy you gotta protect yourself
Great review, i am strugling with the low sensitiviti and indeed i have the small tube. ordered the better tube now. Thanks! btw love the James May voice over.
@@TonyAlbus I also like yours - your business model is also particularly inspired. If I ever decide to make this channel pay for itself, then your chosen model is one that I would consider...
@@project-326 Thank you! ...its still hobby, but i like it a lot and that maybe shows... maybe it will be a business someday. thanks for the compliment.
i improved mine by flashing radpro onto it. the preinstalled firmware is garbage, and radpro is not :) also radpro has a setting for particle clicks, which is enabled by default. it also adds logging via the usb interface and a good averaging algorithm.
Such a good review , while watching it had feeling it comes from great and big youtuber, and now when I noticed 427 subs only , wondering why u don't have more. Where is issue.
so you mean that I am not a "great RU-vidr" then? 🤣🤣🤣 Not sure why the YT algo doesn't like me, probably because I routinely tell it to go and get f**cked...
I finally managed to do it! I successfully reviewed a product and didn't mention the Gamma Scout (PoS) once. What is a PoS? Its a Piece of $hit, of course...
I bought the device even after seeing this video because I don't mind tinkering. It's absolute trash. Even sitting on top of my ENTIRE BOX of spicy rocks, it only measured 1.03 uSv/h. My other cheap (and more expensive counters) scream. Lol Do you think changing out the tube to the J321 impacts the factory calibration?
@@Terrastomper Wow, that is true dedication to the art of "'tinkering"! There is no way to know for certain, but it looks like they just changed the tube and the firmware is the same as the old version. After I added the J321 to my device, the levels were a lot more normal (a little on the high side in some cases).
They must have changed the software also, to reflect the lower cps conversion into uSv/h. I have now changed my tube to the original J321 and it works, giving around 2.5 higher cps. But the uSv value is of course way to high. Of course the uSv is not accurate for anything, even on the original model, as its only calibrated for CS137, and even that, giving some errors due to some sensitivity even to hard Betas. But now its more the twice bakground. @@project-326
The UI and feature set suggest to me that it's trying to be more like a gamma dosimeter than a general-purpose counter. G-M tubes that have a bit of metal shielding to keep out betas and low energy photons ("energy compensation") have energy response curves such that you can estimate gamma dose rate (within a couple tens of percent) from the count rate - IF properly calibrated. However, there's a big problem in that this thing doesn't seem to have a way to recalibrate it in the settings menu. So better hope whatever conversion factors it comes programmed with are accurate I guess. The marketing absolutely bills it as a general purpose device suitable also for x-rays and betas though. No idea why since it seems halfway usable as a dosimeter but doesn't have any of the features you'd want in a general-purpose counter. Maybe there are liability issues if someone relies on it for safety and it fails?
Hi, thanks for the comment. Please take a look at my latest video on this device, the firmware upgrade. Calibration factors are fully adjustable in that 3rd party firmware. There are also factors such as dead-time compensation.
My original J321 FNRISI GC-01 has a 516 SMD resistor at R38. I bought an unbranded GC-01which had a J613 tube and no resistor at R38. Replacing the 613 with a 321 did improve but still seems a bit low compared to the original. I'll try adding a 516 SMD resistor at R38 and see if it improves.
I'm making a new video about the UV sensitivity of GM tubes (the second part) and a key aspect of the video is about the production tolerances of the power supplies used in products like this, so keep an eye out for that, it might help to set the loading resistor. I am going to be asking viewers that have detectors like this, to help with participating in some experiments - a sort of crowd sourced experiment. I am hoping that if enough people get involved, we can actually all learn something new. I hope you will be able to join in the experiment?
Very interesting review with positive suggestions - I can now confirm mine has the J321 tube so hopefully is as good as it can be. Their products are certainly well designed by and large but have some issues.
I do agree about their products being good value for money, but this product is the first time they created a radiation detector, I suspect that learning curve was steeper than they expected.
Hi, 1) LOVED the review and the direct statement whether it is a POS or not 😂thanks for keeping it real bro.😁👍👍👍 2) Do you sell these units after modding them or can you as we are a Bodyguard agency in Australia and have been advised to purchase a quality one...and so far you are the only one we have come across that make sense.. Any help is greetfully appreciated! 👍 Cheers
Personally, I would buy a better counter for a professional application. If you take a look at this channel, there is a video review of the Bosean FS5000, which is a far better device... ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Nbz_Nbqgehc.html
Wow! What a wonderful review. The FNIRSI brand makes all kinds of test equipment. Such as the: $165 FNIRSI DPOX180H 2 Channels Digital Phosphor 180Mhz Oscilloscope. However , after watching this video I am leery of this brand. If they dumb down their products I will pass. 😎 Thank you.
I am actually wondering if this was done due to issues with the availability of the J321 tube. I bought my replacement J321tube for about $12 on Taobao, but the other locally made types are about half that cost on the same platform. Many GM tubes are made in Russia, so this might be impacted by the war in Ukraine. I say *might*, I don't have any hard data.
I could not resist to buy another of these, just to confirm the change of tube. And as you are writing, the replacement tube makes this unit a piece for the junk-yard! So folks: until Fnirsi change back to a usable tube - Dont buy! It appears that its a third, even shittier tube, HH614 in the one I bougt
Thank you for this review, very helpful. I ordered one of these geiger counters, and mine has a HH614 tube in it. I'm not sure how that compares to the J321, but like the J614, it's much smaller and also has a metal cathode.
unfortunately, that one seems to be about the worst variant they have put into this product. Do you have any test sources or anything else to compare with? I strongly suspect that your sensitivity level will be very low.
I've just opened the device I bought from Amazon UK, and it's even worse with an even smaller tube inside. The tube inside is unlabelled and has double sided tape and foam holding it in place. Doesn't even have the mounting for a real GM Tube. I can show you the photos.
Yes, I have seen from the comments, the company has found an even cheaper GM tube, it looks like a Christmas tree light... The pad for the J321 should still be present on the PCB and if you get a replacement J321 tube, it is supplied with the clips that solder into the board.
The Bosean FS-5000 suddenly has dropped in price from 70~90 to around 55,- and i can confirm it has the J321 tube and data export via USB and ticker. i thank that is also a very interesting GMcounter
I have that very device in my hand right now, it is an excellent device and I will be getting that video uploaded as soon as I get though the current backlog.
I have one that came with the J321 GMT. It still has the resister that you removed. Would it work better if I removed it? Any suggestions would be greatly appreciated. Thanks
If it ain't broke, don't fix it. The anode resistor should be matched with the tube, when they changed the tube, they changed the resistor. Some unis that came with the J321 used a 10M resistor, others can without.
Thank you! In my case there was J321 tube but also the resistor marked 5105. edit: And in the case someone, like me, will have problem with FNIRSI GC-01, the right hole is indeed for reset button (just imagine how hard that was to write in the manual).
It was read on Reddit that there is probably a bug in the FNIRSI brand's firmware that occurs when the dose time exceeds 99 hours. After that, the display was no longer updated and the device can only be operated “blindly”. Can you please test whether this is the case?
I'll keep the dose meter running and let you know if that crops up. It does sound like a very simple bug to fix, so I doubt if that bug lasted very long at all.
@@project-326 Okay, I'm very excited. The error manifested itself in such a way that when switching on the logo still appeared and then a lot of ASCII characters quickly ran through in the bottom line of the display. I already had such a faulty device in my hand, but at the time I didn't know the cause or the solution. The owner had simply left it on because he wanted to test the battery life. In the next comment I will post two links that have to do with the problem, please check whether they are marked as spam.
Hi. I love your material. I need a current recommendation for a geiger counter in order to test a vehicle from Fukushima Prefecture that is currently in my driveway. I appreciate any input you have.
For contamination measurement, you will probably need something more sensitive than a Geiger counter. Perhaps take a look at the Radiacode review on my channel, this is better suited for your application.
I am back to this video after a month or so , and I can see you doubled your number of subs, great work mate and keep good work, to be honest came just to see some information you already provided in this video as no others did and I am not expert in this part of electronic. So this video is very useful for me, and going to review some other product of same type , so to see how good is one I got. Only bad thing so far is I don't have any of testing source of radiation to test my detector. Will try to test something soon with X-ray scanners. And again when editing this comment like 12 hours later, you got 4 more subs. It looks too me u going to grow fast now. Gratz
thanks mate! Have a look on the mining data base here to find something locally! www.mindat.org/ if that fails, just try ebay for some fun sources.... Personally I find that sources that are hard to come by are the ones I love the best...
If so, one element that was unclear from your upgrade video was what to do after removing the extra loading resistor. Leave the space empty? Solder a different resistor? Connect the terminals with a plain piece of wire? Sorry, I have only a basic theoretical understanding of these things, but certainly not a practical one! Also, are there any precautions to take when taking the meter apart, so as not to break anything? (Edit - no, there are just 4 screws, which are retained in the housing, so you don't lose them. The battery is on the back panel and connected with a couple of wires, but there is lots of room.) Update, I opened mine up, and it was an easy process. I discovered I have an even smaller J613 tube (the new board is designed for it , as there is an outline for it). There are connection holes for a larger tube, I think, but will they be connected on the under side of the board? And will the 321 come with a pair of holders that fit? Also, it appears the loading resistor you removed in your previous video is no longer present. I wish I could post a photo.
I have seen an updated PCB design that used the even more crappy J613 tube, the race to zero, on this product design continues unabated. In the end, I used a 20M loading resistor on my device.
I just found out mine is a counterfeit. There are multiple versions of counterfeits and mine is exactly the same as yours. So it’s not really Fnirsi fault. On the other hand as others mentioned, they had a newer hardware revision and replaced the tube with J613. This is definitely on them. BTW I don’t think the tube you showed in the video is J613 as it should be shorter.
@@project-326 Thank you very much for your reply. Your videos, in addition to being entertaining, are very informative. Thank you and good luck in your future work.
2:18 Always buy from the official store. Even then you get things with no branding, e.g. my RD Tech TC66 meter where there's no company name on the meter itself.
Typically, here in China, the unbranded version is made by the same factory as the branded one. This happens because the brand doesn't want to pay for the tooling and certifications and pushes those costs onto the factory but in return, the factory can then sell the product but not with their original brand customers' marque.
Perhaps use a telephone type coiled cable. I also thought about this a while ago, 3D printing a custom enclosure for the tube. Instead of using spring clips to hold the new tube 'wand' to the side of the device, I was thinking about using a magnetically secured wand and 3D printing the instrument-end magnet holder with a shape that matches the wand shape itself to ensure a better grip. BTW, I have found that a cheap selfie-stick grips the device pretty well so this is also a nice option for ground surveys without the need to visit a orthopedic doctor afterwards. I just did this to help with surveying the tailings heap of an old uranium mine - I'm currently working on that particular video...
the changes that have been made to this product have occurred in the last couple of months, so you probably have the good version! It a shame that this product has now been hobbled in such an awful way.
@@andreafavero4250 I know that horrid feeling. I only bought my RC102 a couple of months ago, and just before they reduced the price by $100. I seem to be particularly unlucky, a similar thing happened with the KC761 too. Fuckty-fuck.
@@andreafavero4250 The Radiacode 103 has just a bit better resolution. 8.2% ±0.4% FWHM (Full Width at Half Maximum) versus the 102 with 9.5% ±0.4% FWHM. You’ll need to be doing some serious Gamma spectrometry to notice the difference.
@@project-326it's alright my man, I actually bought two for the black friday event and I have literally zero regrets. It's not like the 103 makes mine less godd at what they do and yes, it's annoying that we didnt know earlier it was going to come out but I have no hard feelings agains the company, also because a product so well designed that can perform gamma spectroscopy shouldnt cost this little. And also I want to thank you thorough review that made me go for it. I absolutely love mine and I will give the second one to a friend of mine because he travels a lot and it will be interesting to see the radiation maps :)
Hey there, I use this Geiger counter around the house. When I tried it on a smoke detector, it went to 5 sieverts but a couple days later when I constantly tried it again, it only went to 1.96. I tried things like: letting it get used to natural radiation levels or resetting the cumulative but still nothing. I know about radiation but this confused me! Please give me advice!
Thanks for the comment, hope I can help in some small way... First of all, I really hope you mean 5 uSv/h, otherwise you have seen a fatal dose. The issue with close up measurements of things like Am-241 based smoke detectors is that it is basically a point source of weak gamma rays and this means that the exact way you hold the detector is going to make a big difference. Also be aware, the tube fitted in you device might be the cheap one that has a solid metal cathode and so the 'geometry' of you measurement can become even more critical. Hope that helps?
@@project-326 Thanks so much man! This helps so much. I can see how this Geiger counter could be problematic in an actual dangerous situation. I'm quite young and I'm really interested in radiation, is there anything in a house that could make my Geiger counter go off?
I have 2 of this devices the first has the brand name fnirsi and has a j321 tube the second is blue colour the brand is joy-it from simac electronics in germany and has M4011 tube made in 2023 what is your opinion about this tube??? thanks in advance!!
Actually, somebody else already did it. I am making a video about this firmware upgrade and the video should be finished in a day or so. Make sure you are subscribed to be notified when that is released.
hey man, thanks for the video, wish i saw it sooner. I bought one and it doesnt work at all. Has the small tube in it but im lucky as the resistor is not there and the tube connectors for the larger tube are on the board as well. Im in Australia and was wondering if the j321 on ebay are legitimate? thanks
If you are going to buy tubes, best to buy new ones. Take a look at the Manutek4000 channel for the issues that can happen with eBay tubes. He bought J321's on eBay and they were all useless.
@@RWE870 It is kind of hard to measure that. Normal DMMs have an input impedance of 10M, which is in the same order of magnitude as the anode resistance. I don't remember exactly, but measuring before the anode resistor gave about 380 to 400V
Hi thanks for doing this video. I had ordered one of these on Amazon before seeing your review. On recieving the item i opened it up and it appears to have a J321 tube so at least thats something. Im not sure if its a goid idea for me to go at it with a sokdering iron as ive never really used one. Something i would like to know is more about the setting in the device. I bought it more out of curiosity than actually needing one but i have no idea about the readings. Also is there a more in depth video of fitting the upgrade to gain the audio clicks? Im looking at is as a bit of a project and a learning tool. Can you recommend a type of sample to test it with too please?
Hi David, Thank you for the comments and questions. The first thing to say is "if it ain't broke, don't fix it". As for other videos, there are a couple more on my channel, but look around on the channel page (I don't have many videos), there is one for a firmware upgrade, that might be of use to you. You remind me of myself "I bought one out of curiosity" and now "where can I find test samples?". I think that many of the folk who are regular viewers found themselves with a new hobby through exactly this process! :-) E-bay is a good source of test samples. Be careful buying uranium glass, much of it is fake but things like ionization chambers from smoke detectors and alike are useful sources.
I have 2 of this the first is with name on it fnirsi and i opened it and has a j321 geiger muller tube the second is blue colour and brand is joy-it RAD01 by simac electronics it is sold in germany in conrad store and in other parts of europe like greece i opened it also and i was amazed it has a m4011 geiger muller tube made in 2023 what is your opinion about this tube in this device?
@@project-326 yes but no name have the crappy j613 tube!! The fnirsi brand has the j321 tube!! do you know information about the M4011 tube?? I found on google it is quite good
isnt .2 to .3 microsieverts on the high side for background radiation? i am thinking of upgrading my own tubes because mine was also originally reading an average of .1 and i thought it might also be underreading levels but everything ive read says .1 should be around the average for bg radiation
Indeed it is, after making this video, I discovered that the loading resistor should not be removed but adjusted to match the PSU (the voltage is very erratic between devices). With a 10M loading resistor, the readings became a lot more reasonable. Here in Shenzhen, I normally see about 0.18 nSv/h when averaged over a reasonable period of time. When I made this video, it was summer in this tropical region and the humidity was over 85%, but when the winter came, and with it the lower humidity, I noticed that the tube voltage was getting too high...
If I open it and it comes with the one it was originally designed to have, does that mean Its alright? Or do u think stock from them is still gonna be horrid
I have a problem. There is no resistor in my model. I have change the tube and add capicitor. Now it worka better but Im not sure if voltage on tube is right.
@@sietra Hi! It was too late when i found this great review.... mine came with a shorter metal tube and no resistor... i measured 200v dc on the tube. Wich capacitor did you add (the one to make the sound or another)? I guess J321 wont work anymore without other changes... Thank you!
@@project-326 Hi! Great video! I'm going to do the sound mod... already have the capacitor. Any chance you would make a video to save the even crapier version of the tube? Measure 200v on the even smaller tube. They must have changed the multiplier circuit. Do you have a hi-res photo of this section of yours? Thank you anyway!!!
I got mine and i can confirm it uses even more cheap and shit tube that already discounted version J613. It doesn't even has a name. I found it on Ebay as simply "HG Geiger Counter Tube". Looks simillar to J613 but is is much shorter instead 85mm inlength its around 51mm. Even less surface area = even less sensitivity. However it doesnt have that loading resistor on PCB. Maybe it is alredy modified power supply? Do not know if i can even use aftermarket J321 tube anymore.
Did you figure it out? I bought one too and it has a tube 47 mm in length, again with no markings. Mine doesn't have a loading resistor either. It seems that they changed the board design: the tube is properly mounted with it's leads going through the board, around the halfway point. The PCB markings for the J321 tube are still there though.
@@oskarantola2616 I since bought another radiometer. Pripyat RKS 20.03 Polaron Dosimeter with two tubes SBM-20 side by side. Much older and higher price but also much more sensitive and quite respected among the community of users. Still planning the upgrade the FNIRSI one even might be able to measure the voltage with hi impedance oscilloscope in work. Will see how it goes. Will report here if successful. PS by the description you have the same tube as me. Was your in some way secured to PCB other than just by wires? Mine was on wires on one end and flipping in the breeze on the other end of the tube. I put some double side tape under it to stop it from vibrating the wires. They would eventually break I suspect.
@@josifvissarionovich5320 Looking forward to it, hope you're successful! Mine already has some double-sided tape in between the tube and the PCB from the factory. Does your PCB have markings for the smaller tube, too? Also, I measured that the high voltage does still come to the J321 fitting contacts so perhaps this isn't a lost cause. The little tube seems to fit the description of a HH614 GM tube, though no markings. The recommended operating voltage for the HH614 is 420 V, which gives me hope that the power supply might have enough voltage for the J321.
@@oskarantola2616 So is mine, bought 2024, Feb. 1st on amazon: About 50mm short tube without any markings. No fuse type holders, directly soldered to the PCB. No loading resistor. I measured about 320 volts at the tube with a DVM. Today I installed a J321 tube without any changes at the HV stage. The GC-01 has about 5 to 8 times better sensitivity. With the short tube readings were about 2-3 times less than a BR-6, no it is about 5 times more than BR-6. But on normal radiation a reading of ~0.50uSv/h is much too high (BR-6: 0.10 uSV/h). @studio326- thank you for that very good video!!! @wolf1403
@@wolfganglehmann2717 Does this mean that the meter isn't calibrated correctly for the J321 anymore? Could the problem be fixed by installing an older firmware?
I bought my product named GC-01, on 03.08.2024, it even has FNIRSI GC-01 printed near LCD, however it uses vastly different board. it doesn't have supporting pins fot the tube at voltage outputs, it uses some nameless tube (maybe J613). Is there any possibility of perhaps mailing You the photos, so You can judge, if it's possible to mount the J321 tube on this board ?
there must be 2 versions randomly sold. one with the original tube and one with the smaller tube. i bought it a week ago from fixco and it has the big tube.
I think it has a lot to do with which vendors are holding stock of the older devices. Typically, the guys with the older stock will be motivated to sell quickly by lowering their prices. Money tied up in stock for these small 'nobody brands' is pretty tough to deal with, and frankly if they are just drop-shippers, they won't know which model is which, which model has a good tube and which has a $hitty one (they probably didn't even see, or test, a single sample of the product before buying several thousand of them, they typically just look at Amazon sales numbers for other brands selling the same OEM product).
not sure, you just need to check the operating voltage range for the tube. You should also check the tube supply, in this product there is a wide tollerance. If you want to know how to do that, there is some information in the video link here about constructing a high impedance measurement probe (A DMM will apply a high load to the PSU and pull it down to a fairly low level). ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-2e-BhAZg9d0.html
So after installing the j321 tube and upgrading firmware, it worked great. Until it didn't. Next time I turned it on it didn't read anything and it ended up throwing a fault after 3 minutes or so of sitting.. any suggestions?
did you remove the loading resistor? You could try putting this back, the tube voltage on my PSU was quite low but on other unit I have seen much higher voltages.
@project-326 I did not actually, saw the update before hand. The power supply on the board took a crap somewhere. Only getting 2-4v at the positive of the GM tube. Little unit be dead
I-131 is incredibly active, a half life of just over 8 days and yes, both of the gamma lines should be very easy for this device to measure. The two beta decay modes might not generate a measurable effect in the downgraded version of the tube, ie the HH442 and the J614. With the J321 tube fitted, you will be able to measure both the gamma and beta emissions.
Nice video. Could you be more specific on the type of algorithm you would prefer to see on this device? It seems that the embedded mcu is an stm32 clone, so a custom firmware could be developed.
At the simplest level, an easy to implement filtering method is to make the averaging time window length inversely proportional to the rate of change of the counts. Obviously, there needs to be fixed limits on the length of the averaging window. An alternative might be to apply some averaging but with the newest samples having more weight that older ones. A more complex solution could be an adaptive filter. None of these is beyond the processing capabilities of even a very simple MCU, it just requires taking the time and care to tune this for the balance between speed of detection and stability of measurement.
Maybe, the Bosean FS-5000 changed back after my video on that device. It would be nice to think that this little channel had a positive effect on the product!
You probably mean the 'robot' voice but I do always like to look on the positive side of things, so I wish to thank you for comparing me to one of the smartest humans that ever lived! 🤣😂🤣😂😅😂🤣
Just got mine few days ago, i do have the J321 tube but the resistor you mentioned is also there, should i attempt to remove this? The only other rework i see on my pbc is they added a nice battery holder for the cr1220
if it has the correct tube, then don't change anything, the resistor has been matched to the tube. I have seen several different values for the load resistor in the comments, the one on mine was originally very low and thus pulling the tube voltage too low for J321 to correctly operate. Do you get normal readings for background, etc?
@@PlagueDoctorX312 It will be for matching to the tube type. This is just to make sure that the tube is operating correctly (Geiger mode). The calibration, ie counts/min to uSv/h will be in the firmware.
Hey, thanks for the tip! I can't find this one on Taobao so I have done something I don't normally do, I have contacted the company to see where I can buy a sample. I like the look of this device - many thanks for finding this! I really hope it does turn out to be the unicorn of low cost devices...
well now i feel so lucky taht my 2 fnirsi gc-01 order six mounth apart from each other have both the j321!!! thnak you for that review ! do you have a video about what thrshold value i should put in there?
I assume that you mean the alarm threshold， right？ I normally have mine set to 1uSv/h. If I'm in an area that has dose rates higher than that, I probably want to find out why...
@@offroadbaddude1 Actually, I'm British, my family is from a typical English south coast seaside town. Not sure if I will ever go back there though. I have lived here in SZ for nearly 2 decades and during that time the UK has had more than a few collective 'brain farts' that has set the nation back by about 2 decades. So when I visit, it's like the land that time forgot...
@@project-326 well this explain that!! brain fart are common in canada too ... people's brain freeze in the winter so every spring they repeat the same mistake ... i rather stay close to my wood stove !!! maybe global warming is not a bad thing after all 😂
Mine has J321 tube and the resistor seems to be added from factory, not after the build. Can I still remove it from the pcb? Why have they lowered the voltage to 280V?
Be careful with the voltage measurement, a standard DMM will massively under-read due to the low impedance of the input (usually around 10M ohms). After making the video, I found that the tube voltage rose - I live in a tropical region and did the video whilst it was still very humid, later in the year, once the rH fell, I noticed that the tube was giving some discharge due to the voltage being too high. To measure the tube voltage, you can take a look at my "UV Vs Geiger 2" video, there are instructions for how to build a probe to measure these very low current power supplies. It seems that the power supplies are pretty poor in terms of the unit-to-unit voltage tolerance, so you might be best to measure the voltage you are getting and then adjust the loading resistor to match you particular unit.
interesting… I bought mine labeled as Fnirsi a year ago and it came with the J321 tube. However have the resistor that you removed soldered to the PCB but it doesn‘t look reworked. Does anyone else have the J321 with the resistor in place?
My has some weird even cheaper version of that J613 shit tube. Weird because it is much shorter. It should be 85mm instead it is 51mm barely. Less surface area i guess even less sensitive... However it doesnt have thar rezistor soldered. Its empty. Maybe it is alredy modified power supply? Do not know if i can even use aftermarket J321 tube anymore. I can try to measure voltage however my multimeter impedance would load power supply therefore i will got wrong measurement. It would take oscilloscope with much higher imput impedance wich i do not have.
That is catch 22, the date code is usually recorded on the PCB. That said, this company has chopped and changed between tubes, so the only way to he sure is to open it up and look at the tube. I guess the logic could be as follows: If it is a J321 tube, then there is no need to send it back. If it isn't, you could always update it? ;-)
@@project-326 Thanks for the reply! I did decided to open it up, and it has the J321 tube, just like the pic in your clip above. Also, there was no center screw, just the four corners. Maybe this is a newer update?! I don't have any standard sources to check, but it did agree with the readings taken via a radiation safety Geiger Mueller counter.
sorry for the late reply. That does depend upon if you feel that you can do the mod, I'm the ham-fisted type so I have to go really carefully with the soldering iron...
ok, thanks! I would need clear instructions on how to do it... I have read that it is also necessary to recalibrate the high voltage that supply the tube and bring it to the manufacturer's recommended rating...
That's a really difficult one to answer, it really depends upon what the application is. With low-cost devices, there is always something missing from the spec...
The values recorded for my Am-241 button was about 3.4 uSv/h, which is on the higher end of the spread I see from my collection of detectors, but within range of what I would expect. Before changing the tube, the device would not even register the Am-241 source...
All the versions are made by the same factory, the FNIRSI commercial sales team confirmed that to me in an email, and also that all of the products (branded and unbranded) recently changed to the new tube. There must still be a lot of stock of the older version kicking around. Some people here in the comments have confirmed the new (crappy) tube on both branded and unbranded devices, others still have the older tube on recently bought devices. I guess it depends upon which Amazon vendor supplied the unit. Eventually, all of these device will be using the new tube, which is a shame...
I had 4 of these but 2 of them were not working right. They showed randomly low measurements. But they didn’t show anything at tests with uranium glass. So only two were useable and showed the right values at testing. If you buy these test them before you risk your life with these cheap devices.
Well yes and no. Yes: this is definitely problematic over technically advanced adversaries. No: is isn't a problem over your own country and that is where the US has its own surveillance fleet deployed.
But if you collect stones or plates like „Fiesta ware“ and you have a device that doesn’t show the right measurement and you use the item often. Then it could be risky to buy a cheap device without testing it before using.
The LED output signal, sorry I didn't show that bit, with hindsight that was a little tardy of me. If you pause at 9:55, the other end is connected to R33, at the side that is shown downward in this photo. I will add this to the description, thanks for letting me know!
Because the capacitor results in a positive pulse at the beginning of the LED pulse signal, it will energies the peizo sounder via the transistor. If the alarm is active, the negative pulse at the end of the LED pulse, will cause the alarm signal to be briefly interrupted and this allows the particle sounds to still be heard, albeit, as interruptions to the alarm sound.
I just got one of these and I would say its closer to a piece of shit than a piece of shit! I will change the tube and do the click mod however its very slow to respond. I'm sure if I put a piece of real shit on my radioactive source it will react quicker than this meter does so I'm not sure its even worth doing the mods. Surely the crappy averaging algorithum can be fixed with a new firmware ?????. update. I just opened it and the tube is only about half as long (45mm) as the shitty one you showed in yours so it looks like it just gets worse with time. That resistor is now gone too.
Yes I'm sure you can just fit it and it should work. I measured 307v across the shitty tube so it might be even a but higher than that. The better tube needs 350v so I'm pretty sure it will be fine.
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