GQ GMC-800 Geiger Counter User Guide

Revision: 1.00

Date: Oct-2023

Manufacturer: GQ Electronics LLC

Overview

The GQ GMC-800 digital Geiger Muller Counter is a U.S. NRC compliant, portable, and convenient device designed for industrial, commercial maintenance, research, evaluation, simulation, and other analytical or scientific applications. It is suitable for use in industrial plants, public utilities, hospitals, universities, laboratories, and electronic repair shops. The device features built-in audible and visual signals to indicate radiation levels and can be used for radiation detection and monitoring in both indoor and outdoor environments. It automatically records data, continuously monitoring radiation levels and logging data into internal memory every second. Users can analyze this data by connecting the GMC-800 to a computer and using the provided software. The GQ GMC-800 is equipped with a high-quality color LCD module and a user-friendly graphic interface. It also has one front LED indicator.

The device features a Type-C USB port for communication and external power supply/charging of its internal rechargeable Li-Ion 3.6V/3.7V battery. The battery can be charged with a standard wall adapter, allowing for continuous data monitoring. The GMC-800 can operate solely on the wall adapter, providing freedom from battery limitations and ensuring consistent, accurate measurements. A real-time clock is integrated for time-related data logging.

The USB port facilitates communication with the GQ Geiger Counter Data Viewer software, which allows users to download time-stamped radiation history data for future reference and analysis.

Specifications

Parameter	Value
Range of dose rate indications	0.00 to 2000 µSv/h
Range of exposure dose rate indications	0.00 to 200 mRem/h
Range of registered beta radiation energy	0.25 to 3.5 MeV
Range of gamma radiation energy	0.1 to 1.25 MeV
Range of registered X-ray radiation energy	0.03 to 3.0 MeV
Reproducibility of indication	20%
Gamma Sensitivity Co60	22 (cps/mR/hr)
Alarm levels by CPM	0 to 999999 (continuously)
Alarm levels by µSv/h	0.00 to 9999 (continuously)
Alarm levels by mRm/h	0.00 to 999 (continuously)
Date indication	YYYY-MM-DD (continuously)
Time indication	HH-MM-SS (continuously)
Elapsed time indication	99 years (maximum)
Detectable Radiation Range	β, γ, x (0.1~3 MeV)
Instrument Background	0-2 pulses/s
Working Voltage	3.6-3.7V
Display	Color LCD dot matrix, back lighted
On board Memory	2M Bytes flash memory for data storage
Power Consumption	25mW – 125mW (count rate dependent)
Power Supply	3.7V Li-Ion battery / USB power

This device is calibrated to GQ Electronics' strict QA standard and eligible for calibration to U.S. Nuclear Regulatory Commission (NRC) regulation 10-CFR-34, 10-CFR-35, ANSI/NCSL Z540.3-2006(R2013), ISO/IEC 17025:2017(E), MIL-I-45208A, and traceable to the National Institute of Standards and Technology.

Packing List

GMC-800 main unit.
USB cable
Quick start guide

How it works?

The GQ-800 Geiger Counter uses a Geiger tube to detect radiation. When radiation passes through the tube, it triggers electrical pulses that the CPU registers as counts. The basic unit for count rate is CPM (Count Per Minute), which indicates the radiation level and can be converted to other units like µSv/h or mR/h. Upon powering on, the GMC-800 displays the background radiation reading in CPM, reflecting the ambient radiation detected at that moment. This reading can vary by time and location; for accurate measurements, an average value over a longer period may be necessary.

Caution

Avoid making measurements when the battery is low.
Keep the Geiger counter dry. Use a sealed plastic bag to protect it from moisture.
Avoid making measurements in direct sunlight.
Avoid direct contact with radioactive material; use a sealed plastic bag if needed.
Turn off the unit when not in use.
Store the unit in a protective pouch after use.

Background Safe Levels

Hardware Setup

The unit has four buttons on the front: Key1, Key2, Key3, and Key4 (from left to right).

Power Up: Press and hold Key4 (power) for 3 seconds to turn on the unit. Check the battery level ?. Charge the battery fully before first use; this may take several hours. A fully charged battery icon will be solid.
Set Date/Time: Press Key4 to enter the menu and set the date ? and time ⏰. This is crucial for accurate data timestamping.
Display Timeout & Power Saving: Set the backlight timeout in seconds to minimize power consumption. Enable Power Saving mode to turn off the LCD display after 30 seconds of inactivity.
The unit is now ready. You should see the background CPM rate when no radioactive source is present.

Software Setup (Optional)

Before connecting the GMC-800 Geiger Counter to a computer, download the application software and install the USB driver from www.gqelectronicsllc.com.

For Windows 10/11, no USB driver installation is required. Earlier Windows versions may need a USB driver to communicate with the application software. Running GQGMCGeigerCounterUSBDriverV4.exe installs the USB driver.
GMCDataViewer.exe is used for viewing data on a computer.

For technical questions and support, visit the forum at www.GQElectronicsLLC.com/forum.

For the latest software, visit the software download page: www.gqelectronicsllc.com/comersus/store/download.asp.

Verify USB Driver Installation in Windows (Optional)

After connecting the GMC-800 to a computer, check the Device Manager to see the assigned COM port (e.g., COM5). Selecting this COM port in the data viewer or data logger software establishes the connection to the GMC-800 Geiger counter.

(Visual description of Device Manager showing COM port and GMC Data Viewer software showing connection)

GQ GMC Geiger Counter Multi-Function Keys

The unit features four multi-function keys: Key1, Key2, Key3, and Key4. Their functions change dynamically based on the current menu context.

Key1: Toggles between four display modes: Dose Rate ☢️, Graphic ?, Dosimeter ?, History ?, and Menu ⚙️. In the menu screen, it exits the current menu. In data input mode, it deletes the last character. Holding for 2 seconds reads the current value in Dose Rate mode.
Key2: In Dose Rate and Graphic modes, changes the reading unit. In menu mode, acts as the UP ▲ key. In History mode, changes the reading unit. In a menu with a popup message, cycles through predefined values.
Key3: In Dose Rate and Graphic modes, changes the reading unit. In menu mode, acts as the DOWN ▼ key. In History mode, changes the reading unit. In a menu with a popup message, cycles through predefined values. Holding for 2 seconds enters menu mode.
Key4: Powers the unit on/off (hold for 3 seconds). In Graphic mode, switches between Total, Max, and Average readings. In menu mode, acts as Confirm/Select/Enter ✔️.

Power Saving Mode

The factory default power saving mode is ON. In this mode, the LCD backlight ? dims after 30 seconds of idle time and returns to normal when any key is pressed.

Graphic User Interface (GUI)

Graphic Icons:

Battery Status: ?
Battery Level: e.g., 90%
Data saving enabled / (History data): ?
Alarm enabled: ?
Speaker Enabled: ?
Vibration Enabled: ?
USB Connected: ?

Additional indicators show the current display mode, reading unit, and color safety alarm level (Green for safer, Red for less safe). The current date ? and time ⏰ are also displayed.

Popup Windows

Popup windows display current status/values of selected features. These can be changed only when displayed and are stored after a 3-second timeout if no key is pressed.

Display Modes

Dose Rate Mode ☢️

Displays readings in CPM, µSv/h, mR/h, and CPS. Key2 and Key3 toggle between these units.

(Visuals showing Dose Rate in CPM, µSv/h, mR/h, and average CPS per minute)

Graphic Mode ?

Shows graphs of radiation levels over the past 60 seconds and past 60 minutes. Displays Rate and Average values for CPM, µSv/h, mR/h, and CPS. Key2 and Key3 toggle between units.

(Visuals showing Graphic Mode for CPM, µSv/h, mR/h, and average CPS per minute with time-series graphs)

Dosimeter Mode ?

Displays accumulated dose in µSv and mR, rate in µSv/h and mR/h, elapsed time, and current CPM. Navigation keys allow selection between µSv/h and mR/h.

(Visuals showing Dosimeter Mode for µSv and mR with rate, average, elapsed time, and CPM)

History Mode ?

Displays historical data stored in memory, starting from the first timestamp. Shows preview, next timestamp, average CPM, current max CPM, and previous max CPM. Navigation keys allow moving through timestamps and data points.

(Visual showing History Mode preview with data points and a graph)

Menu Mode ⚙️

The menu screen allows selection of special function items. The left side lists main menu items, and the right side shows submenus. Press Key4 to select a main menu item, then navigate the submenu.

(Visuals showing Menu screen navigation and Click Sound ON/OFF selection)

Settings:

Click Sound: Enable/disable audible clicks (ON/OFF).
Alarm: Configure alarm settings.
Alarm Threshold: Set the radiation level (in CPM) at which the audio alarm ? will trigger.
Beep Volume (Alarm): Adjust the alarm volume (OFF, 5, 15 MAX).
Vibration: Enable/disable vibration alerts (ON/OFF).
Display:
- Theme: Select between LIGHT and DARK display themes. The default is LIGHT mode.
- Dark Theme: Customize font and graphic colors using RGB values.
- Backlight: Adjust LCD brightness (Level 1 to MAX).
- Power Saving: Enable/disable power saving mode.
Save Data: Set the data saving frequency (Every Second, Every Minute, Every Hour, or OFF).
Erase Data: Permanently delete all history data ?️. Requires confirmation.
Set Clock: Set the device's date ? and time ⏰.
Factory Reset: Restore the device to its original factory settings. Requires confirmation.
Calibration: Access calibration settings, primarily for qualified facilities. Allows adjustment of values for different calibration points (CPM, µSv/h, mR/h).
Tube Voltage: For professional calibration purposes only.
About: Displays device system information, including Model (GMC-800), Revision (Re1.00), Serial Number, and Manufacturer (GQ Electronics LLC, Seattle, WA, USA).
Exit: Exit the menu.

Navigation keys are used throughout the menu for selection and confirmation.

GQ GMC Data Viewer Software

The GQ GMC Data Viewer is a free utility software available for download from the GQ website. It allows users to:

Download history data from the GMC-800.
Perform real-time monitoring with graphics when connected to the GMC-800.
Save history data in .bin or .csv (MS Excel) format.
Synchronize the GMC-800's date and time with the computer's.
Set user-defined automatic date and time synchronization periods.
Utilize the GQ Terminal feature for detailed communication protocol exercises.

(Visual description of the GQ GMC Data Viewer software interface)

GQ Terminal

The GQ Terminal provides direct access to the GMC-800 communication protocol. Users can send commands via the software or type them into the command box. It supports commands like GETVER, GETSERIAL, GETCPM, and many others for device control and data retrieval. Detailed communication protocol commands are available at www.gqelectronicsllc.com/downloads/download.asp?DownloadID=62.

An optional software, GQ GMC Data Logger PRO, offers advanced features for various Geiger Counter brands.

(Visual description of the GQ Terminal interface)

Online Geiger Counter World Map (GMCmap.com)

GMCmap.com is a free, open-protocol map service for Geiger Counter users, providing space to share radiation data. Registered users can manage multiple Geiger Counters at different locations and store history data. Users can publish their data by setting privacy properties.

Software

GMCmap accepts data submitted by any software. The GQ Geiger Counter Data Viewer software is recommended for automatic data submission.

Auto Submit Data Protocol

To use automatic data submission, users must register on GMCmap.com to obtain a User Account ID and Geiger Counter ID. The auto-submit data URL format is: http://www.GMCmap.com/log.asp?id=UserAccountID+GeigerCounterID+CPM+ACPM+uSV. At least one reading (CPM) must be submitted.

(Visual description of the GMCmap world map interface)

Applications

Stationary Application

The unit can be placed in various locations for stationary monitoring of radiation and long-term surveillance. With a wall adapter, it can monitor data continuously, 24/7.

Other Important Technical Details

USB Port: Standard mini-USB port for data communication, external power, and battery charging.
Data Collection Time: Radiation data is collected continuously, with measured data transmitted to the CPU every second for processing.
Extend Battery Operating Time: Enable Power Saving mode and turn off the speaker if not needed. If a fully charged battery lasts less than 3 hours, it may need replacement. Use a standard 14500 (14 x 50.0 mm) 3.6V-3.7V Li battery or rechargeable Li-ion battery. The unit can operate with non-rechargeable batteries; select the battery type in the unit menu.

Third Party Software Developers

The GMC-800 uses an open application protocol (GQ-RFC1201). Users are encouraged to develop their own software based on this protocol and share it. For questions, contact support@gqelectronicsllc.com. The GQ-RFC1201 protocol can be found on the software download page: www.gqelectronicsllc.com/comersus/store/download.asp.