Review on 📟 Radiation Alert RangerEXP: Advanced 2" Geiger Muller Detector with Bluetooth & Free Observer BLE App - Enhanced Radiation Detection with Protective Boot by Shawn Tolbert

I have an electronics background and am a keen physicist but bought this because I love gadgets; I don't see much practical use for it unless it's WWIII. On the rare occasions when I go stone hunting or gem viewing, he will be with me. So my review is more from a consumer point of view. The processing and functionality is great. It's easy to use, the menu is intuitive. It has a speaker that clicks on each account; The speaker is front facing and can be temporarily covered with tape or your finger. Or you can just turn it off from the menu. The backlight has a 7-second timer, or you can set it to Always On, a setting that many devices lack. The backlight doesn't seem to use much battery power, so I usually leave it on. It seems accurate enough. I have a couple of test sources, a Zn55 gamma source and a Po210 alpha source. It registers a roughly expected amount for both and it's good to see that it recognizes the Po210's alpha channel well. Background account as expected. You can send this to a US based manufacturer for NIST calibration. It's only $60 so I could do it. Excellent quality probe, very durable. It's all metal and has a nice handle. The head contains a GM pancake tube and has a protective shield over a mica membrane. It comes with a simple plastic cap to keep dirt out and also acts as an alpha filter. The main unit has a plastic body and feels a little cheap, but it's functional. I don't like membrane plates - they wear out faster. Worst of all is the battery compartment, which seems to have been added after the fact. Batteries are difficult to insert and remove and sometimes seem to break in the process. Good that the battery life is long. There is no external power supply or battery. However, the batteries work. The battery indicator only shows 3 bars instead of 4 when fully charged. I ran it on rechargeable batteries for about 100 hours and it still shows 3 bars. A wild guess is I'm getting around 300-500 hours, which is more than normal (800 hour specs with alkaline). The included cable is quite stiff so I replaced it with a 4 foot RG174 50 ohm cable. The measured values have not changed with the new cable. It's much easier to use and the extra cable foot allows the sensor to be worn cross-body. It comes with a nice, easy-to-grip, soft rubber sheath, as well as a lightweight vinyl sleeve with a velcro closure on the back that allows for one-handed use. I'm giving 5 stars because overall this is a really good detector for the price.