Once logged in you will be presented with a large map and collapsible input form. All input variables are entered into the form by expanding the relevant section and entering either a value or choosing from an option.
Beneath the side-form are two buttons: SAVE will store your settings as a template so you can recover them quickly in the future and CALCULATE will perform a calculation using those settings and present the output on the map.
Beneath the map are function buttons which provide access to additional features.
To the right of the map is a colour key which represents received signal strength in either dB, dBm or dBuV/m.
Click on the map to place your transmitter
The system uses OSM based web mapping offering high accuracy street mapping and satellite imagery for the entire world.
To flip between the layers, click the layers icon in the top right. You can also manage radio layers on the map from here.
You can navigate the map by clicking and dragging then zoom using either your mouse rollerball or the controls in the top left.
The map uses EPSG 3857 (Spherical mercator) projection which layers are re-projected to for total accuracy
The first panel contains the most important values needed for any calculation:
Save your settings by clicking the SAVE button
If you plan to use the best server API then getting this field right is essential.
To calculate the total effective radiated power (ERP), enter the antenna gain within the ANTENNA section
For a GSM cell tower use 30km radius
The second section contains geographic information including the transmitter’s location, heights for the transmitter (above ground level) and distance units.
There are three available co-ordinates formats: Decimal degrees, Degrees-minutes-seconds and NATO Military Grid Reference System (MGRS). Select a format and then click in the map to have the location automatically update.
You can override the values with a custom location or click the Google earth icon to synchronise the location with Google earth (requires Google earth sync layer from bottom left menu to be open first).
The update mode can be further controlled by disabling the orange icon in the middle of the screen making it manual entry only. Click the orange icon next to the longitude box to disable it.
The metres or feet toggle will change distance units for heights, clutter and radius
The third section contains advanced settings related to antenna radiation patterns. It allows a choice between pre-made templates or a custom pattern based upon user supplied values. For both methods, there will be two adjacent images shown which depict the horizontal (bird’s eye view) and vertical (side on) radiation patterns. For more on antenna patterns see the antenna patterns section.
Novice users should select the default DIPOLE.ANT (Omni-directional monopole)
Save your pattern by downloading the .ant file beneath the image
You can manipulate the gain value to accomodate other gains and losses in your system. For example, a system with 9dB antenna gain and 3dB line loss could be said to have a positive gain of 6dB.
ERP = Transmitter Power - Feedline Loss + Antenna GainExample: 25dBm ERP = 20dBm Tx RF - 3dB feedline loss + 8dBi antenna gain.
The fourth section contains advanced settings relating to the receiver(s) settings. An incorrect value here can result in unrealistic output.
|Path Loss||dB||Ignores RF power. Used for showing terrain loss|
|Received power||dBm||Shows received signal based on all options|
|Field Strength||dBuV/m||Shows electric field strength based on all options|
|Bit Error Rate||BER (%)||Digital comms. 50% = 0.01, 60% = 0.001, 70% = 1E-4, 80% = 1E-5, 100% = 1E-6.|
The Bit Error Rate (BER) mode will reveal a hidden input value for modulation / Signal to Noise Ratio (SNR). The noise floor is fixed at -114dBm for a 1MHz wide signal.
|Irregular Terrain model (ITM)||20-20,000MHz||US NTIA general purpose model used by the FCC|
|Line of Sight (LOS)||All||Line of sight model used to determine existence of obstacles.|
|Okumura Hata (Urban)||150-1500MHz||Cellular model optimised for urban areas where transmitter is >30m AGL.|
|ECC33||700-3500MHz||ECC33 model for cellular and microwave communications|
|SUI (WiMax)||1.9-11GHz||Stanford University Interim for WIMAX|
|COST231-Hata (Urban)||1500-2000MHz||European GSM1800 and CDMA2000 cellular model optimised for urban areas where transmitter is >30m AGL.|
|Free space path loss||20-100,000MHz||ITU-R P.525 model which assumes no terrain obstacles exist in the path.|
|Irregular Terrain model with obstructions (ITWOM)||20-20,000MHz||Claims to be an enhancement to ITM model with increased diffraction logic but has been found to be unreliable above UHF.|
|Ericsson 9999||150-1900MHz||Ericsson model for cellular communications up to 1900MHz|
|Egli VHF/UHF||30-1000MHz||General purpose VHF/UHF model. More conservative than FSPL|
The ITM model is an advanced general purpose model ideal for most users and comes with knife edge diffraction built in.Next to the model selection is a fine tune option which offers either a reliability percentage level (for the ITM model) or discrete variances based on environment. An urban variant is much more conservative than a rural/open variant.
1 Watt handheld PMR with -70dBm receiver sensitivity
Same with unrealistic -120dBm receiver sensitivity
The receiver sensitivity is very important and must be set carefully to create accurate output, Use -80dBm if you are not sure
The fifth section lists advanced options for defining man made obstacles (clutter) and ground conductivity. The features here will help advanced users achieve the most realistic coverage plot for an area, especially in suburban or extreme climatic environments.
If your antenna is at ground level (Ground wave propagation), the terrain type will greatly affect signal attenuation
If your system's antenna is high up above the ground (Space wave propagation), the radio climate will affect signal attenuation
|Maritime temperate (Land)|
|Maritime temperate (Sea)|
The final section's options do not affect propagation results although in the case of resolution they do alter the granularity. They only determine the cosmetic formatting of results after calculation.