Blog
This is where we write about building Waveshed, a browser-based tool for line-of-sight and RF propagation. Some posts trace where the name comes from. Others get into the models, the terrain data, and what it takes to run a coverage engine right in your browser. New here? Start with Getting started.
Trees now block line of sight
A viewshed can now treat OpenStreetMap forest as opaque canopy, so what you see is what stands above the trees. Where the data is good, and how to switch it on.
Free RF calculators that show their work
A growing set of free RF calculators that draw what they compute and cite their sources, launching with fifteen. The blog will spotlight one tool at a time.
Antenna height vs transmit power: which actually extends your range?
Doubling transmit power buys 3 dB. Doubling antenna height buys 6 dB over open ground, and it is the one lever that reduces the 16 dB a ridge costs instead of paying it.
How accurate is browser terrain, really?
Waveshed reads elevation from a global composite: ~30 m over most of the world, ~2 m in Britain, ~10 m in the US. What that means, and going finer with the QGIS plugin.
Eight megawatts over the Alps to Zürich
In 1979 Roger Schawinski put Radio 24 on a 2,900 m Italian peak aimed at Zürich, 130 km away. A 50 kW transmitter and a directional array turned modest watts into megawatts. A lesson in site, ERP and directionality.
A viewshed for radio: LOS vs RF
Line-of-sight shows what is visible. RF (ITM / Longley-Rice) shows where a signal actually reaches and how strong it is. How they differ, and when to use each.
What can you see from the summit?
Drop a point on a peak and a line-of-sight viewshed shows exactly what is in view: which summits, valleys and huts you can see, and where a trail holds its sight line.
Why we called it Waveshed
Watershed to viewshed to waveshed: where the name comes from, and why a terrain-based RF-coverage tool earned a word of its own.
Coming soon
- Resolution, range, and speed: the three-way trade-off
- ITM on the GPU vs the CPU
- Which earth radius? 6371 km, WGS-84, and the 4/3 radio horizon
- Buildings as obstructions: what the model includes, and what it leaves out
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