Satellite Link Budget Calculator

EIRP is built from Transmit Power converted to a logarithmic dBW scale before Transmit Antenna Gain is added, so EIRP always rises as Transmit Power rises across this calculator's full 0.001 W to 10,000 W range -- but because it's a log scale, doubling the wattage adds roughly 3 dB, not a doubled dB figure. That's the same convention every real link-budget spreadsheet uses, since decibels let power, gain, and loss terms all be combined by simple addition and subtraction instead of multiplication and division.

Yes, across this calculator's full 0.1-100 GHz range at fixed distance: Free Space Loss rises as Frequency rises, because the Friis equation's wavelength term shrinks as frequency increases, and a shorter wavelength means more path loss over the same physical distance. This is exactly why higher-frequency satellite bands need larger, higher-gain antennas to close the same link as a lower-frequency band at the same distance.

Carrier-to-Noise falls as Link Distance rises across this calculator's full range, because greater distance increases Free Space Loss (via the Friis equation), which directly reduces Received Power while Noise Power stays fixed at a given System Noise Temperature and Bandwidth. A geostationary link at 36,000 km therefore needs substantially more EIRP or antenna gain to hit the same C/N as a low-Earth-orbit link at a few hundred kilometers.

No -- Carrier-to-Noise falls as System Noise Temperature rises across this calculator's entire 10 K to 10,000 K range, holding other inputs fixed, because a hotter receiver front end (antenna, low-noise amplifier, and receiver combined) produces more thermal noise power via k·T·B while Received Power is unaffected. This is why real satellite ground stations invest heavily in cryogenically cooled or low-noise-figure receivers to keep System Noise Temperature down.

No. Link Margin here only compares Carrier-to-Noise against a fixed 10 dB reference threshold, which is a simplification -- the actual required C/N for a real link depends on the modulation and coding scheme in use and the target bit error rate, and this calculator does not subtract atmospheric attenuation, rain fade, antenna pointing loss, or polarization mismatch, all of which reduce real link margins below this best-case estimate.