Arthur Harris wrote:

"CW" wrote:

Very little power is necessary in space. I had a QSO with an astronaut on
MIR with a 3 watt ht. With nothing in the way, it will go on virtually
forever.


The signal will decrease by 6 dB every time you double the distance. MIR was
about 250 miles above Earth, and you could establish communicaion with
fairly low power when it was overhead. On the other hand, Mars is about 35
million miles away! You'd need a LOT more power and antenna gain to contact
Mars.

Art N2AH


Voyager 1 is just over 90 Astronomical Units or 8.4 billion miles from
the sun, transmitting with approximately 2 watts and signals are still
being received here on earth. How do you account for that?

JJ wrote:

Voyager 1 is just over 90 Astronomical Units or 8.4 billion miles from
the sun, transmitting with approximately 2 watts and signals are still
being received here on earth. How do you account for that?

Inspired design, careful implementation, meticulous attention to
nit-picky details, enormous antennas, cryogenic cooling of the
receiver front ends, and 65535-bit-long GOLD codes sent straight-up
for "1" and inverted for "0".

It's amazing what can be pulled out from under the noise floor when
only (50% of the sequence)+1 bits need to be received correctly to
achieve unambigous decoding.

--
Should array indices start at 0 or 1? My compromise of 0.5 was rejected
without, I thought, proper consideration.

(Stan Kelly-Bootle)