Coverage Mapping

Clear the program by selecting FILE - NEW NETWORKS to get a fresh start on this example.

Basic Map
Go to FILE - MAP PROPERTIES on the menubar. Pick a Centre for the map using one of the options provided. Also select the size of your map in pixels and the kilometer height of the projection. (Note this program was written by a Canadian, so metrics are the rule.) My example settings are as follows:

This will draw a 400x400 map centered just south of Elkhart IN that is 250km square. See Here You can also use FILE - PICTURE PROPERTIES to draw different varients of the map. (SRTM data will be downloaded to create the map.)

Setting Up Coverage
The two most important points to consider in creating a coverage map is the STATION and the LISTENER. In Radio Mobile both are considered "Units" in a "Network". To create coverage you need both units.
Go to EDIT - UNIT PROPERTIES on the menubar. Define a unit by name and enter the coordinates using one of the options. Once you have entered a unit you can save it to your cities list. I recommend this for any station you will be using on a regular basis. Create the "unit" for your station (one in Elkhart is shown here) and then create a "unit" for your listener. THE LISTENER UNIT IS VERY IMPORTANT! Mapping will not be possible without a listener. You do not need to provide a location coordinate for the listener. (Setting units only works AFTER a base map that includes that map point is drawn as the altitude assigned to that point is pulled from the map in memory.)

Next, go to FILE - NETWORKS PROPERTIES on the menubar. Here you will define the network that the units (the station and the listener) are in. Name your network (if you want to) and select the proper frequency range. Note that the program does not have a selection for circular polarization. I've chosen horizontal, but stations with a stronger vertical signal may want to choose vertical.

Then click on SYSTEMS. Enter your station as System 1. For ease of use, set the Transmit Power as the ERP, with no line loss or antenna gain. Antenna height is in meters above ground level. You can save the system to your radiosys.dat file for later reuse. Again, I recommend saving your main station. My Example:

You also need a system for the listener (logic: can't listen without a radio). The listener isn't going to be transmitting, so that power setting is irrelevant but I have set it to the program's minimum. Antenna height is 9.1m to match the FCC's f(50,50) table calculation (even though we know listeners don't drive around 30ft above ground). I've saved this listener to my radiosys.dat file as well.

Finally click on MEMBERSHIP. Check the box next to the station and the listener "unit"s. Also check the system connected to each unit. Your station unit needs to be linked to the system defined for the station (which defines the ERP and HAGL) and your listener needs to be linked to the system for the listener (0 ERP and 9.1m). You can force a different HAGL if needed.

When you are done click apply.

Seeing Coverage
Now we are ready to do our first contour map. Select VIEW - RADIO COVERAGE - SINGLE POLAR. This is a quick way of drawing coverage. For our example select the following: Centre Unit: WFRN FM Elkhart - Mobile Unit: Listener. The network and "Centre Tx - Mobile Rx" should select themselves. Radial range needs to be enough to cover the range you want to map. (200km will work for the example.) We want to plot a Fill Area in Rainbow Color - check those boxes. The threshold for our drawing is 40 to 100 dBu. Azimuth Range is 0 to 360, step 1 (steps of .1 to 10 degrees are possible). And our station has an omni pattern. Hit apply. You will want to redraw picture in gray mode if asked, and for the sake of this demo "keep coverage in picture". All that gives you this map:

Note the HAAT button. Clicking this will give you a text HAAT report for the "Centre Unit" specified.

Adding Roads and Cities
Thus information is subject to change as RadioMobile relies on third party maps.
Go to EDIT - MERGE PICTURES and select the type of map you would like to overlay, and select "Multiply" as the Operation. Click Apply and a map is overlaid on the coverage you have drawn. If you "keep in actual picture" the overlay will stick. Notice that in the left picture the key for the signal strength is messed up by the overlay. This can be fixed by going back to FILE - PICTURE PROPERTIES and APPLY to clear the working map, then EDIT - MERGE PICTURE procedure again, and finally drawing your POLAR COVERAGE again. Much cleaner, as shown on the right.
(Old picture ... newer map overlays are better.)

Save Your Masterpiece
You can use FILE - SAVE PICTURE AS to save your map. If you downloaded and installed the jpg .dll you can save as a .jpg as well as a bitmap. (I prefer BMP and then convert to a GIF using another program. JPGs are blurry IMHO, and BMPs are large!)
Saving all the data that went into your creation can be done on the file menu as well. You can have multiple saved networks and maps.

Cartesian radio coverage can also be drawn to show multiple signals (such as WBCL/WBCY/WBCJ shown here). This shows you the coverage from the strongest station. I prefer to do multiple pass Cartesian coverage maps instead of rainbow maps. It can take a long time to draw a multiple station coverage overlap, especially when one chooses to use a solid fill for each band (red for 60-200, green for 50-60, yellow for 40-50) but the results can be worth the multiple passes and delay. Coverage can also be drawn for directional antennas (WCSG shown here).


James Bellaire @ CRTech