3 ms·

Would it be closer to the other value if you factored in the atmosphere, and whatever else is in the way? As an aside, would radio via the moon ever be practic

• drmpeg 3y ago
  No, there's very little loss from the atmosphere at 432 MHz. The 390 dB figure is a misunderstanding of how the path loss is calculated. The poster "wl" took the one way path loss (195 dB) and doubled it. But the moon is a huge reflector and provides "gain". Here's a C program with the correct equation. #include <stdio.h> #include <stdlib.h> #include <math.h> int main(int argc, char **argv) { double d, f, lambda, loss; if (argc != 3) { fprintf(stderr, "usage: moon <km> <frequency(MHz)>\n"); exit(-1); } d = atof(argv[1]) * 1000.0; f = atof(argv[2]); lambda = 299792458.0 / (f * 1000000.0); loss = (0.065 * (1.738e6 * 1.738e6) * (lambda * lambda)) / (631.65468167 * (d * d * d * d)); printf("EME path loss = %f dB\n", 10 * log10(loss)); return 0; } 1.738e6 is the radius of the moon in meters and 0.065 is the reflection efficiency. Satellites make moonbounce impracticable.