GQ GMC-500Plus Geiger Counter Nuclear Radiation Detector Monitor Dosimeter, White

Great product.

For the price point this is a great Geiger counter. It is more than sensitive enough to warn you of dangerous situations and that it is time to exit the area. However, it is not quite as sensitive as the GQ-600+ which uses a U.S. made "pancake" style Geiger Muller tube (I purchased both to compare the units).The GQ-500+ and 600+ come with a flat top "unprotected" 3.7V 2,600mAh Lithium Ion rechargeable batteries, this is the first thing that I replaced with a 3.7V 3,400mAh Japanese button top "protected" battery. It is a tight squeeze in the GQ500+, but the protected cell fits and provides longer run time (approx. >1/4 battery capacity used over 24 hours once the upgraded battery was installed). The onboard charger had no issues with the battery upgrade and charges it as it should using a USB connection (quite quickly I might add)Software for PC interface and expanded documentation is available at the company's website as well as the option to connect your meter via WiFi to allow regular updates to the worldwide radiation tracking website (address included in the documentation on their site) and included on a plastic card that comes with the meter.Easy to use only got 4 stars as there is a learning curve to the buttons that are poorly labeled.Battery Life only got 4 stars because better batteries could have been used (unprotected batteries vs. protected), and a protected 3,400mAh would be preferable to the 2,600mAh unprotected battery that is provided.Note on "Unprotected" vs. "Protected" batteries. The protected batteries actually have a small microcontroller included in the cell that monitors charge levels and will cut off charging at the battery level if it senses an overcharge condition, unprotected batteries will continue to accept charge current even though they are at full capacity. Goolge the difference in the batteries for confirmation.The charge controller in the 500+ seems to act appropriately by cutting off charge current when it senses the battery has reached the proper charge level, and this is goodness. The protected batteries come into play if you want more than one battery available for use and you have a questionable charger for the extra batteries. In my opinion it is a good safety measure on top of an already good charging system in the meter. I have personally seen "thermal runaway" in a Li-Ion cell and it is a most spectacular, and dangerous, reaction when it happens.

This is worth the money…. Just for the fun of it! I have taken it with me many places, just as a conversation starter.

Haven’t found anything worrisome yet but it does work.

ALL Geiger Muller tubes age. If you are checking rocks, granite counters, and habitations for unusual radiation, this is a great device that will last many years.If you are doing background radiation surveys over time, as I do, it is still a great device as you CAN replace your tube every three to five years. When my older counter read higher than my new one, I called them, they reminded me about tubes aging, (Duh! How could I forget!) so I ordered a replacement tube. They have good tech support and stand behind their products. I have two of their counters.Having worked a bit with the high vacuum of physics, I can say that ALL vacuum tubes age as air diffuses in through the glass, reducing vacuum and providing more atoms to become ionized over time. Whether it takes years, decades, or centuries depends on the thickness of the glass. Geiger Muller tubes have to be thinner to detect particles, so age faster than radio tubes. So if you are interested in cosmic rays over time, you will need to replace your tube every three to five years REGARDLESS OF THE BRAND of your device! This company will support you with replacements. I replaced the tube in my older counter already, and it was very easy to do! Great American company, great product, great support.

Great to have in general, extremely accurate and reliable. This will come in handy some day.

The unit is a very advanced geiger counter (to my layman's eyes, anyway). I gave it a three stars on "Accuracy" because I have no way of measuring accuracy. I believe it to be excellent, however. I gave it three stars on "Easy To Use" because it has a pretty steep learning curve for the layman and the instructions assume facts not in evidence -- like assuming I know what I am doing. Also, the instructions tend to not be linear -- i.e., they tell you in the first paragraph the first thing you need to do is set the date and time -- but don't tell you how to set the date and time until you are most of the way through the instructions. The instructions tell you to provide certain data to make contact with your modem Wi-Fi, but don't tell you where to get that information. They tell you to insert additional information to make contact with the national server, but don't tell you where to get that information, either. By working with it for a day and a half I managed to get it to reliably connect to my modem -- but I still haven't figured out how to get it to access the app it installed on my computer to make a record, nor have I figured out how to get it to provide current readings to the national server. Also, it doesn't help that I periodically have to set it aside to do other things, and when I come back I have to relearn everything. All in all, I think it is a fantastic instrument, but figuring it out is quite a project.

This device is spot on. I have tested it with different radioactive samples and it is accurate. It also is accurate with background radiation and just this week I used it to detect extra “activity” due to the large solar flare/CME that sent material to earth. We could even see the northern lights close to where we live. Awesome. Also…. For those that don’e know, antique fiestaware (orange) more than likely is radioactive. Most of the U235 in the plates gave plates some radioactivity, but were a safe source for using to test g counters…… but…… some of those plates do actually have higher concentrations of U235 in them. I came across one that was extremely radioactive. Just be careful if you do get sources to test your device and remember, shielding and distance is protection against radiation. I was actually surprised this device worked as well as it did. I have used the black cat system in the past and I think this one performs just as well.