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lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1

-210dBm RSSI from Voyager 1

There was a thread about how RF signals may look like ... this is an actual RF image of Voyager 1 spacecraft taken in February 2013 by the NRAO VLBA radio telescopes.

the space probe's main transmitter radiates just 22 watts, about the same amount of power as a typical ham radio ... But compared to many natural objects probed by radio telescopes, Voyager 1's signal is actually quite bright.

The dish antenna on Voyager has approximately 42dBi gain. NASA uses a massive 70m dish on earth (»deepspace.jpl.nasa.gov/dsn/antennas/70m.html) to get approx -210dBm RSSI after 18.5 billion kilometers! It takes Voyager's RF signal more than 17 hours and 22 minutes to reach earth at light speed.

The RX LNA is super cooled to reduce noise floor below that level and currently 600-1000 bit/s two way data tranfser is possible.

Soon Voyager will not be able to receive commands from earth because it uses older 1970s RX LNA with much higher noise floor. But it will still send data towards earth ... until fuel and battery runs out.

SETI folks can also detect Voyager 1 signal: »setiquest.org/forum/topic/baudli···-1-redux


Inssomniak
The Glitch
Premium
join:2005-04-06
Cayuga, ON
kudos:2
-210.. Wow


DaDawgs
Premium
join:2010-08-02
Deltaville, VA
reply to lutful
Yes, but don't forget in just a few years Veger is going to meet up with the alien intelligence (BORG) after that she will come back around... Then it is going to get ugly.

But yeah, -210 dBm That is bad ass.

robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

1 edit
Actually V'ger probably met up with the parent(s) of the BORG. But I doubt Voyager will meet them in our lifetime.

And agreed, -210 dBm, wow!

Stumbles

join:2002-12-17
Port Saint Lucie, FL
reply to lutful
I was gonna say, most LNAs have a noise floor of around -100 or so. Now I see how they mitigate some of that noise floor on the ground.