FRS/GMRS Radio Mapping Guide
Radio mapping[1] is the process of creating a visual representation of radio signal strengths and coverage areas across specific geographic locations; in this case, a team's Service Area. A radio map highlights areas with strong, weak, or no signal, helping organizations understand coverage patterns, identify dead zones, and optimize communication infrastructure.
Introduction to Radio Mapping
Scenario
A disaster has struck the Portland metropolitan area. Routine communications methods (e.g. cell phones) are disabled, and NETs are self-deploying to their Staging Areas/Incident Command Posts. After making some initial assessments, Incident Team Leaders begin deploying strike teams to render aid in the surrounding neighborhoods.
After dispatching a strike team to travel a specific route, the Incident Team Leader discovers they cannot establish FRS/GMRS radio communications with them. Time passes and nothing is heard. Is the team in a radio dead zone? Have their radios failed? Is the team in trouble? Should the Incident Team Leader dispatch a runner to their last known location? Does the strike team need the assistance of a follow-up strike team? Where are they?
Meanwhile, the strike team discovers they can no longer communicate with the NET Incident Command Post. How can they reestablish communications? Should they double back to the last point of communication, risking wasted time and physical exertion? Should they continue forward and hope to reestablish communications at a future location? How long will that take? If the team is in serious trouble, should they detour from their route to call for help? If so, in which direction?
The purpose of FRS/GMRS radio mapping is to provide some solutions for addressing these types of questions in an already stressful situation.
Method
FRS/GMRS mapping may be conducted by placing a two-person team, one Radio Operator and one Scribe, at a proposed NET Incident Command Post location. Rover Teams report to the Radio Operator as they stop at specific locations throughout the NET Service Area. The Radio Operator and the Rover Teams record the radio voice quality for the conversation, as they heard it, at each location. The radio voice quality values for each reported location are then used to create color-coded maps for Incident Command staff and Strike Teams for use during large-scale disaster response.
Goals
The primary goal of a Radio Coverage Survey is to measure the radio voice quality of FRS/GMRS radio communications within a prescribed NET Service Area.
The radio voice quality values may be used to:
- Validate prospective primary and backup locations for a NET Incident Command Post;
- Determine radio voice quality at points throughout the NET Service Area;
- Scope out potential locations for an FRS/GMRS repeater or relay sites.
The process of radio mapping with team members will also:
- Improve radio skills;
- Increase familiarity of the NET Service Area;
- Allow practice of elements of the Incident Command System (ICS);
- Build team cohesiveness; and,
- Cultivate an understanding of radio communication coverage patterns to reduce uncertainty and anxiety during a major disaster.
Radio Coverage Survey Sessions
A team working together can accomplish a Radio Coverage Survey Session in a series of one-and-a-half to two-hour periods. These short sessions enable more volunteers to participate and may be scheduled any time or day of the week.
Several documents available here for download and printing can facilitate a Radio Survey. They include:
| Document | Download | Last Update |
|---|---|---|
| Radio Coverage Survey Action Plan | [PDF] | 2024.11.10 |
| Radio Survey - Command/Listening Post Log | [PDF] | 2024.09.20 |
| Radio Survey - Rover Team Log | [PDF] | 2024.09.19 |
| Survey area maps | ||
| NET Form 2A Personnel Check In | [PDF] | |
| NET Form 3 Team Leader Assignment Tracking Log | [PDF] |
Radio Coverage Survey Action Plan
The key elements of a Survey Action Plan should include, at the minimum:
- “What we are going to do”: the goals and plan for the survey;
- “Who is responsible for doing it”: participant assignments;
- “How do we communicate with each other”: survey radio protocols; and
- “What is the procedure if someone is injured”: work in pairs, apply first aid, and contact Command Post and/or 911 as need be.
Additional elements of the Survey Action Plan should include instructions for using Survey Log forms and Survey Area Map.
The Radio Coverage Survey Action Plan, including radio protocols, should be reviewed with survey participants in a NET meeting before the first radio mapping session. Additionally, survey participants should review the action plan before each session. A sample Radio Coverage Survey Action Plan is available as a fillable form in the table above or download here, and can be modified for the NET Service Area surveyed.
Command/Listening Post Radio Log
The Command and listening posts use the Command/Listening Post log to record radio voice quality values of rover team communications. This form should include the date, location, survey radio operator and scribe names, radio type (FRS or GMRS), and radio make and model.
The following information is recorded for each survey location:
- Time (use military time)
- Rover team name
- Location (by cross streets, street address, or other place name)
- Radio voice quality value
A sample Command/Listening Post Log is located in the table above, or here.
Survey Area Map
The radio mapping exercise organizer can use My Google Maps or a similar application to create survey area maps identifying key locations. Those locations being:
- Survey Command Post
- Any listening post(s)
- Rover team survey locations
Survey area maps should be prepared in advance and distributed to rover teams at the beginning of the mapping session by the Command Post scribe. Rover teams use these maps to identify survey locations and determine the most efficient path of travel between locations.
A guide to using My Google Maps to create survey area maps is located here. A sample survey area map is located HERE.
Rover team survey locations
PBEM recommends that rover team survey locations should be selected to form a uniform grid across the NET Service Area. A uniform grid is most easily constructed in areas where streets are arranged in a uniform rectilinear pattern. In this situation, survey locations may be places at street intersections. Where long blocks break up a uniform pattern of intersections, survey locations may be placed at specific addresses.
In areas where streets follow elevation contour lines, survey locations may also be placed at specific street addresses or other easily identifiable locations. These locations may be where streets change directions, traverse abrupt changes in terrain, or pass by a distinguishing landmark.
The distance between survey locations should be short enough to eliminate ambiguity in the radio voice quality values in a region. In general, in NET Service Areas with relativity flat terrain, survey locations may be spaced further apart than in areas where elevation changes may obstruct radio signals. Some experimentation may be required to determine the best distance between survey locations. The distance between survey locations may differ in different parts of a NET Service Area.
Taking measurements at too many locations is more advisable than skipping locations and introducing uncertainty into the results.
Survey Command Post
The Survey Command Post should be located at the Primary Incident Command Post as specified in the NET Operations Plan. However, radio coverage surveys may be used to evaluate the suitability of other locations if the Primary Incident Command Post has not been established or is being evaluated for relocation.
The Command Post should be staffed with at least two participants: one person acts as the Survey Radio Operator (SRO), and the other acts as a Scribe. The SRO and Scribe collaborate to decide on a Radio Voice Quality Value and other Rover Team information being recorded on the Command/Listening Post Log form by the SRO. The Scribe complete a separate log form to help collaborate on the information received. The Scribe may also check off each reported Survey Location on a copy of the reporting team’s Survey Area Map. The SRO’s log form should be considered to be the official record and the Scribe’s copy as an aid.
During initial sessions, it is preferable to have the Team’s Amateur Radio Operator (ARO) be the SRO. The ARO should brief participants on effective radio protocol. Other participants should act as the SRO during later sessions to gain experience in the Incident Command Post Neighborhood Radio Operator (NRO) role. If the workload overwhelms the ARO, the NRO role may be established. The NRO would be responsible for all NET FRS/GMRS communication in the Service Area.
Notes and References
- ↑ Also referred to as Service Area FRS/GMRS Radio Voice Quality Survey, but we truncate to "radio mapping" to keep it simple and save money on digital ink.
