System Coverage Planning and Mappin

[Fast1eddie]

Hello,

I would like to learn about how a radio system is planned-let's say Vhf. Are topographic maps used along with the coverage formulas??? I was a two way tech for years but never became involved with the planning process. As a police officer, my interest in radio has been rejuvenated. My jurisdiction (Beaver County) is supported by conventional Vhf frequencies. I reside about 30 miles away and am able to monitor them mobile (Aor 8200 w/Austin Spectra) and at home with Aor 8600 with a discone.

Thank you,

 

[N4DES]

Usually a consultant is utilized to develop the Scope Of Work that would include the targeted coverage requirements. These requirements can vary greatly (outdoor 90% to in-building 95%) and this greatly affects the price.

The selected vendor, upon award of the contract, usually provides coverage maps with the contract specified coverage and this becomes the vendors minimum requirement. During the acceptance stage the contractor is usually required to do "drive tests" of the boundaries specified in the document. If the vendor exceeds it, they get kudo's. If they fail they get awarded with the requirement to construct additional site(s) at their cost.

There is one item that I need to bring up, which is that if the agency selects the tower sites, some vendors will use this as an out for the coverage requirements if they advise that they need a location somewhere else and the customer is unable to provide a substitute location.

Hope this helps.
Mark

 

[slicerwizard]

I would like to learn about how a radio system is planned-let's say Vhf. Are topographic maps used along with the coverage formulas???

Yes, coverage mapping software is used. If you're curious, you can play with Radio Mobile - it's free. Here's a sample image: http://www.cplus.org/rmw/images/brocken.gif

 

[zz0468]

Motorola and Tyco M/A Com use their own proprietary software optimized to their product line. Agencies with their own in-house engineering will use a commercial software package such as ComStudy. Basically, the parameters of a proposed site are plugged into software, which runs thousands of calculations and gives an approximation of coverage. Even things like antenna radiation patterns are entered as data for the programs to use. Antenna manufacturers generally have pattern files that can be downloaded.

The software is pretty good, but it is essential for engineers AND the customers to know and understand their weaknesses.