GQ GMC-300S Digital Nuclear Radiation Detector Monitor Meter Geiger Counter Radiation Dosimeter

The GQ GMC-300S digital Geiger counter is the latest general purpose Geiger Counter. It is developed by GQ Electronics LLC, Seattle, WA USA.

As an enhanced version, it has higher sensitivity to facilitate a lower level radiation detection. It also has LCD contrast control, front LED indicator, analog data port output, new graphic display, speaker on/off features. It also has unique features, such as, record data first play it back later; open protocol for easy application integration; visualize real-time graph, data logging. Portable and convenient with built-in audible and visual signals, it features automatic data recording. It is able to continually monitor the radiation and log the data each second into internal memory.

When connected to a PC, GQ software can download the radiation history data to the computer and the user is able to analyze those data later. the device uses USB port for communication and power. The internal battery can be charged via wall adapter or car adapter.


Technical Specification:

Range of dose rate in µSv/h: 0.00 to 1000.00
Range of dose rate in mR/h: 0.00 to 100.00
Radiation detection: Beta, Gamma, X-Ray
Maximum Dose Reading: 99,999,999.99 µSv OR 9,999,999.99 mR
On Board Data Logging: Every Second CPS for 24 hours, Every Minute CPM for 7 days, Every Hour ACPM for 2 years
Power Supply: Removable and Rechargeable Li-ion battery OR USB power from cell phone charger or any USB port
Internal Flash Memory: 64KB

Can be used for Daily Radiation Level Detection and Monitoring:

Seafood Radiation Detection

Fruit Radiation Detection

I-131 Radiation Treatment Monitoring

Animal Cancer Radiation Treatment Monitoring


Main features:

  • Small, portable hand-held
  • Audio and visual indication for nuclear radiation detection.
  • Dot matrix LCD digital display model with back light.
  • USB Data port for connection with computer/PC/laptop GQ Soft Geiger Counter software
  • Battery charging feature for charging internal battery.
  • USB DC input port for external power input, so that continually monitoring become possible.
  • Powerful counter circuit is capable for handling counting up to 65,535 CPM (Count Per Minute).
  • High sensitivity tube M4011 installed (user can remove this tube install other tube if needed)
  • built-in battery charging circuit
  • On-board real-time clock
  • On-board flash memory for history data record
  • on-board speaker.
  • Dimension: 5'x2.85'x1'
  • 9V battery or DC power adapter operation


  • Text mode provide maximum data information. eg. CPM, Date, Time, Elapsed time, uSv/h, mR/h etc.
  • Real-time graphic mode provide visualized real-time radiation changes, so that much easier to observe the data changes. It also display the CPM rate at same time. In Graphic mode, the ZOOM feature let user to see from lowest to highest graph onscreen.
  • Back light Control to set the back light ON,OFF and timeout. So that to save the power.
  • Battery charging and battery level indicator.
  • Speaker ON/OFF control.
  • Alarm setting. It sets the alarm ON/OFF, alarm type, alarm level.
  • Date time set the real-time clock.
  • Swivel display setting.  180 degree swivel display provides a convenience reading when unit upside down.
  • Three points calibration. For CPM to uSv/h and mR/h conversion
  • Power saving mode let unit keep running at minimum power.
  • Data saving mode selection. let unit record data every second/minute/hour. Up to 7 days history data
  • History data searching
  • and more....

Items included in the package:

  • GMC-300S main unit
  • Rechargeable battery
  • USB cable
  • Quick start guide
  • Download link for SoftGeigerCounter and USB driver for Windows 32 and 64 bit


Please Note: 
Import duties, taxes, charges, VAT, and brokerage fees are not included in the item price or shipping cost. These charges are the buyer's responsibility.

If buyers refuse to pay the above charges, and reject the package, buyers are responsible for the two-way shipping fee (going and return).