Geiger Counter - Digital - Professional - Model # GCA-07W External Wand Probe - ANSI N323A Certification Ready- 0.001 mR/hr Resolution - 1000 mR/hr Range

I purchased this Geiger counter mostly because I live near a nuclear power plant, and I want to be aware of what's going on if there's ever an alarm. I even use the thing from time to time when I drive by the power plant, just to make sure it's safe. I think it's a great value for the money and the fact that you can get it certified by the NRC standards goes to show its reliability and accuracy. It's easy to operate, the instructions are great. It's also fun to use. I've purchased some radioactive samples to Check from time to time, and I believe his counter to be accurate. I bought it here on Amazon. I call it a good investment.

This is a simple unit that’s good for measuring radiation from specific sources. If you want to measure long term exposure in an environment, you can use this to connect to a PC running data logger software. The onboard interface averages exposure over a minute, but doesn’t keep track of anything beyond that. The included documentation and supplemental information on the company’s website are very informative. You get the sense that they probably only sell a handful of these, because the build quality is pretty low, and the instructions look like they were maybe faxed or something. I think this is fine though, because they focused on making the product work well. I used it to measure exposure after a family member received a nuclear medicine procedure. It worked really well for that.

When I received my GCA-07W, I was impressed with the quality of the manufacturing of the product. The wand is made of a thick lightweight plastic. The end of the wand has a metal screen that protects delicate mica window of the GM tube but allows alpha particles to reach the GM tube. It also has a friction fit wand cap that is an additional protection for the wand. The wand cap must be removed for detecting alpha radiation. For the detection of beta, x-rays and gamma radiation you can leave the cap on the wand. The front panel of the GCA-07W has toggle switch controls. Everything is clearly labeled. I love the toggle switches. The toggle switches snap into position which makes changing the settings intuitive and easy. These switches are so much better than those crappy membrane switches you see on other models. I hate pressing on a membrane switch and hoping the switch press is detected. In any case, that is something you don’t have to worry about with this Geiger counter. Aside from easy set up, I was even more pleased with its performance. I must also point out the customer service from the company is excellent. I needed a little help getting started with the Geiger counter. I was transferred to a technical support person who helped me understand how to take background radiation readings. I was also guided to the company’s online nuclear experiments. Now, I don’t remember most of the math I learned in school. But their experiment 1, not only teaches you the right way to measure background radiation. It teaches you, using basic math, how to calculate the Mean (average) and Standard Deviation of the background radiation, what this means and why it’s useful. They have a dozen or so experiments up on the web, I plan to work through them all and report back here what I find. The next thing I did with my Geiger counter was start testing some old materials I had lying around. I removed the cap and the Geiger counter picked up alpha radiation from some old radium clock faces I have. Then I checked an orange Fiesta ware plate. In both cases these samples caused the Geiger counter to emit a loud clear clicking that easily gets your attention. I installed the company’s free Geiger graphing software on my computer. I had a compatible USB cable to connect the GCA-07W to my Windows PC computer. I ran a background count for 30 seconds, then I put the wand by the Fiesta ware for 30 seconds. You can see from the picture, on the left side of the screen is normal background. The right side of the screen is the radiation picked up from the Fiesta ware. I have two other Geiger counters and the GCA-07W outperforms them hands down. I would recommend this unit to anyone needing a well-built accurate Geiger Counter.

This unit is easy enough to use but has on major issue. The toggle switches on the front of the unit are quite vulnerable to breakage because they protrude out from the unit and could easily damage the switch if impacted from the side. There are many low-profile toggle switches available for use and would significantly improve the design. I recommend getting the uranium calibration tin to check the unit. I prefer the clicking sound of the older counters over the beeps on this unit.

No instructions, didn’t know , had to go back to office and download only after signing up with manufacturers website and ask permission. Works as intended.

This is an excellent and accurate tool for measuring radiation. - This Geiger Counter was purchased primarily for disaster/catastrophic situations and I was initially disappointed to discover it wouldn't work with Nickel Metal Hydride rechargeable 9 volt batteries, e.g. "Supreme Power" brand. These freshly-charged batteries test at 8 volts when a voltage meter is applied to the contacts without load. I did some research and ordered batteries with a higher voltage. I am pleased to confirm the GCA-07W Professional Geiger Counter works with "Powerex" 9 volt batteries. My VOM (again "no load") reads slightly over 10 volts when applied to freshly charged Powerex batteries. I am glad I waited to paste this eval as l now rate it five stars. - Incidentally, when I noted this battery problem last month, I sent an email to the company with an inquiry about this issue and, though they didn't have a suggestion, they did get back to me promptly which speaks well of their support efforts. We also discussed a more robust case and switches which they have considered too; it would add significantly to the price, perhaps as much as 50% more! UPDATE Aug 15, 2018: (This update is written in response to some recent questions and answers that came to my attention.) I store my device in a double Faraday Cage. This makes it substantially more EMP resistant. I also bought an uranium ore sample to test calibration. I will probably have it professionally re-calibrated in 3-5 years to see if it is stable in storage. UPDATE 04Jan21: Just pulled the unit out to check calibration, batteries, packaging, etc. Still 5 stars. I perused the negative reviews and was surprised by the report of poor customer support. It was not my experience. Also, with regard to comments about lack of robust design or non-EMP resistant circuits, I looked in vain for the reviewer’s alternative product recommendations? Undoubtedly, for $2000-$3000+, a better product, maybe even “mil spec,” could be offered. So in the meantime, I wrap my unit in heavy foil, a heavy plastic bag, and then place it in an cardboard insulated metal garbage can. :)

I purchased a GCA-07W Geiger Counter through Amazon in Dec 2015. The Counter I received was delivered in perfect condition. Well made, easy to set up and use right out of the box. You can have the GCA-07W NRC certified if you feel it necessary. That says a lot about the accuracy of the product. I purchased the Charting Software and USB Driver Disc directly from Images SI Inc. after receiving the GCA-07W. Everything I needed to connect the GCA-07W to my Laptop or PC was included. I've been using mine for the better part of the last 5 months with no problems or issues. Works great and is easy to use. Images SI Inc. is a great vendor to deal with.

I bought the GCA-07W digital geiger counter to go antiquing and I feel it is a great investment. I also purchased the NRC version for work and will post a review on that digital geiger counter at a later date. Both the certified and non-certified digital geiger counters are excellent devices. I can detect whether or not a radium painted clock (or watch) is real. I can also find radioactive fiesta ware and uranium dyed glass. This instrument has made my antique hunting not only more efficient, but much more enjoyable. I am glad to know that I can detect even low levels of radiation such as those coming off 19th century objects like radium water jars. I feel more secure in my antique purchases and it is a useful hobby instrument. My son loves it when we go prospecting for uranium. And should an emergency occur I have a good device to help deal with it.