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CloudRF KMZ Generator
The CloudRF KMZ Generator is a RepeaterBook Plus feature that produces a terrain-aware radio coverage map for a specific repeater. It uses advanced modeling software to estimate how far the repeater signal is likely to reach based on available data in the RepeaterBook database.
What It Does
This tool creates a color-coded KMZ file that can be viewed in Google Earth or on a map. The KMZ shows estimated signal strength across the terrain, taking into account elevation, antenna height, and power.
This is not a live signal report. It is a computer-generated prediction based on the information stored about the repeater. The accuracy is dependent upon the accuracy of the repeater's data.
Who Can Use It
Only RepeaterBook Plus subscribers have access to this feature. Repeater owners registered as Repeater Record Coordinators can view the overlay on the repeaters they are signed up for.
What Information Is Used
The generator uses the following repeater details:
- Latitude and Longitude – must be verified accurate
- Transmit Frequency – rounded to the nearest 0.1 MHz
- Power Output or EIRP – in watts
- Antenna Gain – if available
- Antenna Height – AGL (height above ground level); if missing, assumes 6 meters
- Bandwidth – determined by analog/digital mode
How Bandwidth Is Determined
The coverage simulation uses bandwidth (signal width) to estimate how well the signal cuts through terrain. Bandwidth is chosen based on repeater mode:
| Mode | Assumed Bandwidth |
|---|---|
| Analog FM (wide) | 25 kHz |
| Analog FM (narrow) | 12.5 kHz |
| DMR / YSF / P25 | 12.5 kHz |
| D-STAR | 6.25 kHz |
| NXDN | 6.25 kHz |
| M17 | 9.6 kHz |
| TETRA | 25 kHz |
If the repeater is listed as analog and has a specific bandwidth set, that value is used. Otherwise, digital mode flags are checked and a standard value is assigned.
What Assumptions Are Made
If some repeater data is missing, the system makes the following assumptions:
| Missing Info | Default Used |
|---|---|
| Antenna AGL | 6 meters |
| Antenna Gain | 0 dBi |
| Line Loss | 1 dB |
| Receiver | Mobile antenna at 2 meters height |
| Receiver Sensitivity | -110 dBm |
| Polarization | Vertical |
| Antenna Pattern | Omnidirectional |
These defaults are designed to reflect a typical mobile user's experience, but they may not match your actual equipment or terrain.
What Could Cause a Map to Be Inaccurate?
Several factors can cause the predicted map to differ from real-world observations:
- Incorrect or estimated repeater location
- Output power or ERP not entered or outdated
- No antenna height (AGL), resulting in low coverage
- Digital mode not marked correctly, affecting bandwidth
- Nearby terrain features not accounted for (e.g., buildings, foliage)
How to Improve the Accuracy
You can help improve coverage predictions by ensuring your repeater’s data is accurate:
- Confirm the coordinates are correct and marked as exact
- Enter either output power or ERP
- Include antenna gain and height above ground level (AGL) if known
- Verify the mode flags (DMR, D-STAR, YSF, etc.) are correct
- Specify analog bandwidth if your repeater uses FM
If you believe the coverage map is wrong, double-check the stored repeater data or report it to RepeaterBook admins for review.
Output Format
The tool produces a `.kmz` file, which can be:
- Downloaded and opened in Google Earth
- Viewed on a Leaflet-based map
The map shows signal strength using colors, from strongest (red) to weakest (blue), based on estimated mobile reception.
Limitations
- This is a model — not a measurement.
- It assumes standard mobile radio hardware and ideal conditions.
- It does not account for interference, weather, or indoor reception.
- Results should be interpreted as guidance, not a guarantee.
Need Help?
If you're unsure whether your map is accurate, compare it to known coverage from mobile users. If there's a big difference, check your repeater data first. For assistance, contact a RepeaterBook admin with your repeater ID and any known discrepancies.