How to map your network:

• 1. Place Your Base (Hub): Search for your home QTH, repeater site, or mountaintop. Tell the app what antenna and power you are using.
• 2. Drop Target Stations: Add remote stations to run point-to-point Line of Sight (LOS) checks. Swap to the "Network" tab to see them all at once.
• 3. Define the Environment: Radio waves act differently depending on the frequency. Tell the app what band you are on and if you are shooting through a concrete jungle or open desert.
• 4. Map Coverage: Click "Generate Coverage" to calculate a massive 360° signal footprint around your site. (Warning: High resolution takes a few seconds!)

Take the Guided Tour

1. Station & Hardware Settings

TX Power (W): The raw output power of your radio. Increasing power only helps the other station hear you; it does not help you hear them.

Antenna Gain (dBi): Gain does not magically create more power. It acts like the reflector in a flashlight, taking your radio's power and squeezing it into a flatter, more focused beam to shoot it further toward the horizon.

Line Loss (dB): The amount of signal lost as it travels through the coax cable between your radio and antenna. Higher frequencies (like 70cm) bleed much more signal in coax than VHF (2m).

dBm (Received Signal): How we measure the signal arriving at the radio. It is a negative number. -60 dBm is a booming, full-quieting signal. -120 dBm is buried in static. Every 3dB drop means your received power was cut in half!

2. Directional Antennas

Omni vs. Directional: An Omni radiates in a 360° circle (like a bare lightbulb). A Directional antenna focuses the RF (like a laser pointer).

Azimuth: Your compass heading (0° is True North, 180° is South).

Beamwidth: How wide your "flashlight" beam is. A 3-element Yagi might have a wide 70° beamwidth, while a Parabolic Dish might have a razor-thin 10° beamwidth. If your target is outside this cone, the signal drops off a cliff.

Front-to-Back Ratio (F/B): How well your directional antenna acts like a shield. If a jammer is directly behind your Yagi, an F/B ratio of 20dB means that jamming signal is massively reduced before it hits your radio.

3. RF Physics & Environment

Fresnel Zone: Think of the radio signal between two antennas as a giant, invisible 3D football. Even if you can physically see the other antenna with binoculars, if a hill scrapes the bottom of that "football," your signal drops. This app defaults to requiring 60% of that football to be clear of dirt.

K-Factor (Atmospheric Bending): Radio waves don't travel in perfectly straight lines; they bend slightly with the curvature of the Earth. A K-Factor of 1.33 simulates "normal" weather. Lowering it to 1.0 simulates a strict optical laser beam.

Terrain Clutter: The topographic map knows where the mountains are, but not the pine trees, skyscrapers, or brick walls. "Clutter" adds a mathematical penalty to simulate the RF absorption of those real-world obstacles.

Operating Mode: Different modes require different Signal-to-Noise Ratios (SNR) to be usable. FM Voice requires a strong, clean signal. Digital modes like FT8 can mathematically dig usable data out of heavy static.

Managing Simulator Expectations

"The app says I have a perfect signal, but I can't hear them!"

The Reality: This tool uses a 90-meter resolution digital elevation model. It knows exactly where the mountain range is, but it does not know about the 60-foot oak tree, the local noise floor, or the two-story house directly across the street from your antenna.

"What does 'Raise Antenna By +5m' mean?"

The Reality: If your path is "Obstructed" or "Blocked", the app calculates exactly how much taller your mast needs to be to clear the dirt out of your Fresnel zone.

"Why does my 2m link work, but my 70cm link fails on the exact same path?"

The Reality: Physics! Lower frequencies (2m) have longer wavelengths that can "diffract" or knife-edge over the top of a mountain ridge. Higher frequencies (70cm, Microwaves) act more like light—if they hit a hill or dense trees, they get absorbed or reflected.

"Why does the coverage map look jagged or blocky on the edges?"

The Reality: The map engine shoots out dozens of mathematical "spokes" (radials) to calculate the heatmap. We balance the resolution so your browser doesn't crash. If you want smoother edges, change the "Cov. Res" setting to Ultra (but be prepared to wait a bit longer!).

"Can I use this for my commercial WISP or 5G cell tower planning?"

The Reality: No. This is built strictly for Amateur Radio, hobbyist experimentation, and educational purposes. It is absolutely not rated for commercial network engineering or life-safety emergency dispatch.

About This Tool

Disclaimer: Theoretical estimates based on public 90m terrain models. Designed exclusively for amateur radio, educational, and hobbyist use. Not for commercial network engineering or life-safety planning.

Privacy First: RF math runs locally in your browser. Terrain data requests are anonymous and never logged.

Elevation calculations powered by Copernicus DEM & NASA SRTM 90m.

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Created by Brandon Beeson KO6HWR Buy Me a Coffee