41 dBm EIRP (20dBm + 21dBi) at his house. - 108 dB Free space loss - first link + 18 dBi antenna gain on the mountain. + 18 dBi antenna gain on the mountain. - 118 dB Free space loss - second link. + 24 dBi antenna gain at ISP. ========= - 125 dBm
According to these calculate communication through the moon is impossible ...
Really communication is, even if to use 10W
Forgive me if I misunderstood your message but let me reply to what I think you are saying.
Yes, communications to the moon is possible with low power. Hams do it with 10W but with more antenna gain. They also use 1Hz or less bandwidth. The symbol rate is about one symbol every 10 seconds or so. If you are going to make a comparison, please be sure that the comparison is valid.
If you want to increase the bit rate you need to either increase the bandwidth or increase the signal-to-noise ratio (Shannon's theorem). Increasing bandwidth increases noise admittance and raises the noise energy in the passband thus requiring a greater absolute signal strength to overcome more background thermal noise energy in the increased passband. This is why you see the required signal decrease as you decrease the bit rate with 802.11b. Sure, if you want to send data at 1 baud you can use a LOT less signal. Is that what you are shooting for?
TANSTAAFL (there ain't no such thing as a free lunch).
-- Brian Lloyd 6501 Red Hook Plaza [EMAIL PROTECTED] Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.360.838.9669 (fax)
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