Chapter 2 - Communications Flashcards
Direct communication
The straight line travel of radio signals between the transmitting radio and the receiving radio.
Repeated communications
Used to strengthen communication signals between radios, increase distance of transmission or increase capacity on the system.
Radio limitations
Distance, physical barriers, deadzones, interference, and ambient noise
ABCs
Be Accurate, Brief, and Concise.
DVRS Repeaters
A repeater integrated with a mobile radio control head that merges the primary tactical channel with the backup simplex channel.
Zones
CFD radio system is categorized into six zones (A, B, C, D, E, and F).
Channels
There are 16 channels per zone in the CFD radio system.
Tower Sites
Tower sites emit frequencies and aid in the sending and receiving of duplex radio communications. There are 8 tower sites strategically located around Calgary.
Radio Systems
Radio systems for the CFD consist of: mobile radios for vehicles, hand-held portable radio’s for fire crews and Digital Vehicle Repeater Systems (DVRS). Radio systems can operate in either duplex or simplex mode.
Duplex Mode (Trunking)
Radio communications are transmitted on one frequency and received on another. All duplex transmissions must reach a radio tower in order to rebroadcast back to other duplex users and/or dispatch.
1. Tactical
2. Utility
3. Training
4. Airport
5. Zone (dispatch) Channel
6. Technical Rescue.
7. Mutual Aid
Simplex Mode (Conventional)
Simplex transmissions are radio to radio and are sent and received on the same frequency. They are “line of sight” and have a limited transmission range local to the area around the incident and will not be heard throughout the city like on the duplex system. They can dramatically improve local site communications for incidents where the duplex system is not providing adequate coverage.
- Simplex channels are unable to reach radio towers, dispatch and duplex/tactical channels on their own. However, with DVRS in operation that can change.
Talk groups
Talk groups is an addressing system where a zone is paired with a channel. If Dispatch assigns an incident Zone C, Channel 7, fire crews communicate on talk group C7; where C7 is defined as a tactical channel.
Personnel tuning in to Zone E or Zone F on channels 1-12 can communicate on talk groups E 1-12 or F 1-12; where they are defined as simplex channels.
Dispatch Channels
Located within Zone B and Zone C of the radio system and use channels (B13-14 and C13-14). Used primarily for communication between Dispatch and apparatus officers.
- B13 north of Bow river
- C13 south of Bow river
Tactical Channels
Located within Zone B and Zone C of the radio system and use channels (B1-B9 and C1-C9).
Utility Channels
Located within Zone A of the radio system and use channels (A1-5). Typically they are for non-emergency use like inspections, hydrant testing, in station training, and community events.
Training Channels
Located within Zone A of the radio system and use channels (A7-A11).
Simplex Channels
Located within Zone E and Zone F of the radio system and use the same channels in correlation with tactical channels 1 – 12 (E1-E12 and F1-F12).
- Simplex channels allow crew members to communicate with each other directly through the line of sight. They are used as a backup when communication on duplex tactical channels start to deteriorate. All simplex channels will have male voice announcements to differentiate from the female voice announced on the duplex channel.
- Contact with Dispatch and EAB notification are possible, however, if a DVRS unit is present and tuned onto the corresponding assigned tactical/simplex channels. The
simplex user is capable of reaching the trunking system via the DVRS.
Portable radios
Portable radios have a unique encoded 6-digit identifier, which is displayed on the main and top LED screens as well as the attached label on the front. CFD 6-digit identifiers range from 760001 to 762000.
Portable Radio Swap
When a portable radio becomes damaged or inoperable, contact a District Chief for a replacement.
- Every radio swap requires updating the damaged radio and replacement radio aliases in the database. DC’s must ensure dispatch completes both.
- When a District Chief provides a replacement portable, it becomes the permanent radio for that “seat position”.
Staffing Limits
There are now staffing limits on apparatus to coincide with the number of assigned portable radios. There are 5 assigned radios per engine and 3 per secondary apparatus.
Riding Between Apparatus
The practice of (probationary firefighters, 3RD or 5TH firefighters) riding between 2 apparatus during a shift is no longer accepted in order to prevent misidentification in a Mayday situation.
Once original apparatus has been repaired, the temporary unit must be swapped back out.
True
Radio Failure
Crews should move to SIMPLEX when “SITE TRUNKING” is displayed as the radio system behaviour is no longer consistent.
Testing a Radio Signal
One- Bad (unreadable)
Two- Poor (readable now and then)
Three- Fair (readable, but with difficulty)-
Four- Good (readable)
Five- Excellent (perfectly readable)
IE- 5 x 5 is excellent clarity and volume; 2 x 5 is poor clarity and excellent volume.