Radio System Coverage Maps - Communications Management

YOUR “BEHIND THE SCENES” ENGINEERING DEPARTMENT
Radio System Coverage Maps
Radio System Coverage Maps: VHF ­ UHF ­ 700 & 800 MHz Narrowband (12.5 kHz) Ultra­Narrowband (6.25 kHz) Analog Digital Single­Site System Multi­Site Networks Simulcast Voted Receivers Paging Systems FCC Contour Maps Broadband Point to Point Microwave Communication System Engineering & Design: Will Narrowbanding change my Radio System’s Coverage? What will happen if I change to a Digital System? How many Tower Sites do I need? Will a Simulcast System cover everywhere I need? Is there a big difference between Mobile and Portable Coverage? A Coverage Map is Worth a Thousand Words. Coverage Maps are an invaluable engineering tool. We are often asked “What If.” It is less expensive to build your system in the vir‐
tual world first. We can help you design the system that fully meets your needs. To create the coverage models, we considers factors such as fre‐
quency, distance, transmitter power, receiver sensitivity, antenna height, antenna gain, variations in terrain, signal obstructions, ambi‐
ent noise, and potential interference. Find the Problem Spots Before They Become a Problem Radio System Design Antenna System Design Intermodulation Studies Interference Mitigation Site Analysis Lightning Protection Pre & Post Sale Support FCC License Assistance Communications Management Group P.O. Box 37 Zimmerman, MN 55398 612­216­3530 Sales@cmg­msp.com www.cmg­msp.com (612) 216‐3530 www.cmg‐msp.com Understanding Radio System Coverage Maps Radio System Coverage Maps represent estimated radio system coverage by utilizing Propagation Software. The computer software uses industry accepted algorithms to predict different levels of signal strength. These levels of signal strength in turn reflect different levels of audio quality and coverage reliability based on the specific site / system data provided. Delivered Audio Quality, abbreviated as DAQ, is a measure of audio quality over a transmission medium. This metric is often used to quantify the quality of audio heard over a radio system. DAQ levels are defined by the following scale. DAQ 5: Perfect. No distortion or noise discernible. DAQ 4: Speech easily understandable. DAQ 3.4: Speech understandable without repetition. DAQ 3: Speech understandable with slight effort. (Occasional repetition due to noise or distortion) DAQ 2: Speech understandable with considerable effort. (Frequent repetition due to noise or distortion) DAQ 1: Unusable. (Speech present but not easily understandable) To apply the DAQ scale to the Coverage Maps, it is generally accepted that: The Red & Yellow sections of the Coverage Map should have a signal strength level to allow for reliable communication (DAQ 5). The Green section of the Coverage Map should have a signal strength level to allow for reliable communication (DAQ 4 or better). The Light Blue section of the Coverage Map should have a signal strength level to allow for reliable communication (DAQ 3.4 or better). The Dark Blue section of the Coverage Map should have a signal strength level to allow for reliable communication (DAQ 3 or better), but may be susceptible to increased noise or reduced signal strength due to physical objects in the way. The un‐shaded section of the Coverage Map may have areas of usable signal strength (DAQ 2), but the level is below the threshold of reliable communication. Coverage Maps are based on a computer model using physical and environmental data. A Communication System’s reliability characteristics can be affected by several factors; therefore no Communication System can provide 100% reliability, 100% of the time.