Calculator Inputs
Example Data Table
These sample cases show how height, terrain, and frequency can affect practical planning range.
| Case | Tx Height | Rx Height | Frequency | Terrain | Typical Use |
|---|---|---|---|---|---|
| Open yard mast | 30 m | 2 m | 900 MHz | 0.85 | Temporary site network |
| Dense urban roof | 45 m | 5 m | 2400 MHz | 0.45 | Camera backhaul |
| Rural tower | 60 m | 3 m | 700 MHz | 1.00 | Long range telemetry |
| Suburban pole | 20 m | 2 m | 5800 MHz | 0.65 | Short point link |
Formula Used
Radio horizon: d = 3.57 × √K × (√Ht + √Hr)
Free space path loss: FSPL = 32.44 + 20log10(fMHz) + 20log10(dkm)
EIRP: EIRP = Tx power + Tx antenna gain − Tx cable loss
Received power: Rx = EIRP + Rx gain − Rx cable loss − FSPL − extra site loss
Signal margin: Margin = received power − receiver sensitivity − fade margin
First Fresnel radius: F1 = 17.32 × √((d1 × d2) / (fGHz × D))
Earth bulge: Bulge = (d1 × d2) / (12.75 × K)
Coverage area: Area = π × practical radius² × sector angle / 360
How to Use This Calculator
- Enter the planned antenna height and receiver height.
- Select the height unit used on your drawings or field notes.
- Enter frequency, power, antenna gain, cable loss, and sensitivity values.
- Choose a terrain factor that matches your construction environment.
- Add design distance and obstruction data for Fresnel clearance checking.
- Press the calculate button to view coverage results above the form.
- Use the CSV or PDF button to save the result report.
Construction Planning Value
Antenna height affects more than wireless range. It affects mast choice, bracing, permits, access, grounding, and safety zones. A coverage estimate helps a site team compare practical layouts before materials arrive. It also helps avoid raising a mast without checking the real path.
Height creates a longer visual horizon. Receiver height also matters. A handheld receiver near ground level has a shorter path than equipment mounted on a wall, pole, scaffold, crane, or roof deck. The calculator combines both heights, so the result feels closer to a real construction plan.
Terrain and Site Effects
Open ground is friendly to radio paths. Dense buildings, trees, steel frames, stockpiles, and temporary sheds reduce practical coverage. These objects may not fully block the signal. Yet they add loss and create weak zones. A terrain factor reduces the theoretical radius into a safer planning estimate.
Frequency is another strong driver. Lower frequencies often bend and penetrate better. Higher frequencies can carry more data, but they need cleaner paths. The link budget section compares power, antenna gain, cable loss, receiver sensitivity, and fade margin. This shows whether the signal can still be heard at the planned distance.
Clearance and Fresnel Space
Line of sight is not only a straight visual line. A radio path also needs space around that line. The first Fresnel zone is this important space. For common planning, keeping about sixty percent clear is a useful target. Cranes, parapets, tree lines, hoardings, and roof equipment can reduce that clearance.
The clearance test checks one obstruction on the path. It estimates earth bulge, line height, Fresnel radius, and final margin. A positive margin means the path is more likely to work. A negative margin warns that the mast may need more height, relocation, or a different relay point.
Better Field Decisions
Use this calculator during early site layout, temporary network design, security camera planning, radio placement, and remote sensor setup. Treat the result as a planning guide, not a licensed survey. Final design should still review local codes, wind loading, grounding, equipment limits, and certified drawings. Good planning lowers rework and improves site communication reliability before crews commit costly equipment.
FAQs
1. What does antenna height coverage mean?
It means the estimated area an antenna can serve from a given mounting height. The estimate depends on horizon distance, receiver height, frequency, equipment power, terrain, losses, and required signal margin.
2. Why does receiver height matter?
Receiver height changes the visible radio path. A receiver near ground level has a shorter horizon. A receiver on a pole, building, machine, or tower can extend the possible line of sight.
3. What is the terrain factor?
The terrain factor reduces theoretical range into a practical planning range. Open ground uses a higher factor. Dense buildings, steel frames, trees, and obstructions use a lower factor.
4. What is Fresnel clearance?
Fresnel clearance is the open space needed around the radio path. Even when two antennas can see each other, nearby obstructions can weaken the signal if they enter this zone.
5. Is this calculator enough for final tower design?
No. It is a planning tool. Final mast or tower work should also check wind loading, structural drawings, grounding, electrical safety, local rules, and manufacturer limits.
6. Why is link budget range different from horizon range?
Horizon range checks geometry. Link budget range checks signal strength. A path can be visible but still fail if power, antenna gain, receiver sensitivity, or losses are poor.
7. What fade margin should I use?
Many planning studies use 10 to 20 dB as a starting range. Harsh sites, critical links, moving equipment, rain, or clutter may need a larger reserve.
8. Can I use this for security cameras?
Yes. It can help plan wireless camera backhaul, temporary site networks, access points, radios, and sensors. Use real equipment values for better results.