YT3CT Skywave Simulator

Rays leave the antenna, hit a virtual-height mirror, and bend back to Earth only if the operating frequency is below that layer's MUF at the ray's angle (secant law: MUF = fc / sin θ).

Operating frequency

Freq (MHz) 14.0

To scale Globe (curved Earth, schematic)

Water effect (sea-gain brightening)

Night mode

D disappears (recombines within minutes of sunset). E's ionization drops sharply. F1 merges into F2, which itself weakens and rises in height.

Simulate Es openings

h′ (km)100

Peak fc (MHz)150.0

Statusclosed

Real Es forms as short-lived, unpredictable ionized patches — not a steady layer. This simulates that: it flickers open and closed over time with a randomized peak fc, rather than sitting at one fixed value. Turning this on switches the antenna to an Es-only hop and hides the other layers, since a real Es opening is a separate, self-contained propagation mode.

D layer (absorbs, day only) 50–90 km

h′ (km)70

E layer 90–130 km

h′ (km)105

fc (MHz)3.0

F1 layer 180–250 km

h′ (km)200

fc (MHz)5.0

F2 layer (always on) 250–400 km

h′ (km)300

fc (MHz)9.0

Antenna (vertical radiation pattern)

Min angle (°)5

Max angle (°)20

Ray count9

Hop builder

Hop 1 target

Hop 2 target

Hop 3 target

Hop 4 target

Each ray is tested hop by hop. It only advances if the chosen layer is active and the frequency is below that hop's MUF — otherwise it punches through right there and the chain stops.

Transmitting at 14.0 MHz

SKYWAVE SIMULATOR — YT3CT

To scale · 4,000 km

Globe: landing distances are exact, but height is exaggerated for visibility, so the drawn angle is not — see the caption under the chart for details.

Ray slope always shows the true takeoff angle.