Technical Guide to GMRS

By Sean D. Liming and John R. Malin

Learn the technical details of General Mobile Radio Service and how it leads to amateur radio

General Mobile Radio Service (GMRS) was created decades ago, but recent FCC rule changes, licensing, and a multitude of GMRS radios make it easy to jump in the GMRS radio communication. GMRS requires a license without having to take a test, thus opening up anyone to get into radio communications. For amateur radio (HAM) enthusiasts, GMRS provides a radio communication solution for family members that don’t have a HAM license. Since GMRS and HAM radios and frequencies are similar, the path to amateur radio from GMRS is an inexpensive way to jump into the hobby. Technical Guide to GMRS covers all the basics of GMRS, tools, and resources to get started. The book covers the following:

  • GMRS history and different radio services
  • Radio basics
  • FCC rules and getting a license
  • GMRS specifications
  • Connecting to GMRS repeaters
  • Learn about different GMRS radios, settings, software, resources, and radio reviewers
  • Radio tools that are also used in amateur radio

Technical Guide to GMRS
Liming, Sean D and Malin, John R

Book Details

Printed Edition: 148 Pages
Publisher: Annabooks (January 2026)
Language: English
ISBN-13: 979-8-9854172-5-8


 

 
 

 

 

Table of Contents: 

1    STAYING CONNECTED   
1.1    GMRS History   
1.2    GMRS Uses and the Gateway to Amateur Radio   
1.3    About the Book   
1.4    Getting the GMRS Licensing   
1.5    Book Page and Feedback   
1.6    Summary: Keep Connected   
2    RADIO BASICS AND RADIO SERVICES   
2.1    Electricity and Magnetism Relationship   
2.1.1    Electromagnetic Field   
2.1.2    Carrier Frequency and Bandwidth   
2.1.3    Power and Line of Site   
2.2    Frequency Spectrum and Wavelength   
2.3    Different Radio Services   
2.3.1    Citizen Band (CB)   
2.3.2    Radio Controlled (RC) Vehicles   
2.3.3    Multi-Use Radio Service (MURS)   
2.3.4    Amateur Radio HAM   
2.3.5    FRS/GMRS   
2.4    Summary
3    GMRS SPECIFICS   
3.1    FCC Part 95   
3.2    Channels and Frequencies   
3.3    Line A and Line C   
3.4    Squelch   
3.5    Tone/Code Squelch (Not Privacy Tones)   
3.5.1    CTCSS
3.5.2    DCS   
3.5.3    Tone/Code Implementation and Confusion   
3.5.4    Example of Tone/Code Squelch (Not Privacy Codes) in Action Part1   
3.6    A Few More Technical Details   
3.6.1    Bandwidth: Narrow versus Wide
3.6.2    TX Power   
3.7    Transmission and Station Identification   
3.8    Summary   
4    GMRS RADIOS   
4.1    The Right Radio for You   
4.1.1    What are you going to use it for?   
4.1.2    Radio Types   
4.1.3    Features to Look For   
4.1.4    Programming Software and Cable   
4.1.5    NOAA Stations   
4.1.6    UHF Radio versus GMRS Radio   
4.1.7    FCC ID Search   
4.1.8    FRS versus GMRS   
4.1.9    Watch Out for Marketing   
4.2    The GMRS Radio Market   
4.2.1    GMRS Radio Manufacturers   
4.2.2    Radio Reviews   
4.2.3    Where to Buy   
4.3    GMRS Radio Technical Insights   
4.4    Wouxun KG-805G   
4.4.1    Features and Tips
4.4.2    Wouxon KG-805G Programming Software   
4.4.3    Wouxon KG-805G Programming with CHIRP   
4.5    Retevis RT76P   
4.5.1    Features and Tips   
4.5.2    Retevis RT76P Firmware Update   
4.5.3    Retevis RT76P Programming Software   
4.5.4    Retevis RT76P Programming with CHIRP   
4.6    Retevis C2   
4.6.1    Features and Tips   
4.6.2    Channel Synchronization   
4.6.3    Retevis C2 Programming Software   
4.7    Retevis RA86   
4.7.1    Features and Tips   
4.7.2    Retevis RA86 Programming Software   
4.7.3    Adding and Removing Channels   
4.8    Mobile Base Station Power Supply   
4.9    Radio Miscellaneous Items   
4.9.1    Alarm   
4.9.2    ANI Match   
4.9.3    Busy Channel Lockout (BCL) or Busy Lockout   
4.9.4    Compand   
4.9.5    DTMF   
4.9.6    PTT-ID /ANI   
4.9.7    Scramble   
4.9.8    Roger Beep   
4.9.9    VOX   
4.10    Summary   
5    WORKING WITH REPEATERS   
5.1    Repeater Frequencies and Tone / Code Squelch   
5.2    HAM and GMRS Similarities   
5.3    Repeaters in Your Area   
5.3.1    myGMRS.com   
5.3.2    Private / Repeater Clubs and Open Repeaters   
5.3.3    Other Sites and Linking Repeaters   
5.3.4    Example Connecting to a Repeater   
5.3.5    Road Trips   
5.4    Repeater Architecture and Manufacturers   
5.5    Two Mobile Radios as a Repeater   
5.6    Retevis RT97L   
5.6.1    Features and Tips   
5.6.2    Retevis RT97L Programming Software   
5.6.3    Example of Tone/Code Squelch (Not Privacy Codes) in Action Part 2   
5.6.4    Example of Talk Around   
5.6.5    DB9 Port Projects   
5.7    Repeater Setup Etiquette   
5.8    Summary   
6    RADIO TOOLS AND DIAGNOSTICS   
6.1    Antenna Basics   
6.2    50 Ohms Impedance and Matching   
6.3    Speaking in Decibels   
6.4    Connectors   
6.5    Antenna Selection and Installation   
6.5.1    Retevis RT76P Example   
6.5.2    Specifications   
6.5.3    Installation   
6.6    SWR Meter   
6.6.1    Using the SW-33Plus for Handheld Walkie Talkies   
6.6.2    Using the SW-102 for Mobile Radios and Repeaters   
6.7    Vector Network Analyzer (VNA)   
6.7.1    nanoVNA   
6.7.2    Software and Hardware Requirements   
6.7.3    Firmware Upgrade   
6.7.4    Configure and Calibrate the nanoVNA for GMRS   
6.7.5    GMRS Antenna Test and Results   
6.7.6    Smith Chart and Antenna Tuning   
6.8    Harmonics   
6.9    Spectrum Analyzer   
6.9.1    TinySA Ultra   
6.9.2    Software and Hardware Requirements   
6.9.3    VNA Test of the Attenuator   
6.9.4    Self-Test and Calibrate the TinySA Ultra   
6.9.5    Firmware Upgrade   
6.9.6    Radio Tests with the TinySA Ultra   
6.10    Feedline Tests   
6.11    Where to Buy   
6.12    Summary   




 





 
   

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