[Elecraft] QRP signals from Pathfinder probe (off topic)

[Fred Townsend]

Mike You can do the math for path loss. The formulas are well known. Perhaps less known is the rest of the story. The probe is using its high gain (dish) antenna, perhaps 20 db. Since it is a dish antenna it must be aimed! The probe is programmed to aim its antennas periodically since it can not be commanded to turn its antenna.
Back at this end, the Goldstone antennas have about 60db gain with cryogenically cooled noise figures of <1. I'm guessing the receiver sensitivity at around ---150 to -170 dbm using a very narrow bandwidth and correlation techniques similar to what is used on GPS receivers. Transmission flight of path is > six hours.
73
Fred, AE6QL

-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of ac5p at sbcglobal.net
Sent: Thursday, July 16, 2015 11:10 AM
To: Elecraft Reflector
Subject: [Elecraft] QRP signals from Pathfinder probe (off topic)

Heard last night on  Nova program that the transmitter on the Pathfinder Pluto probe was 10 watts.  Anyone have a clue as to the signal path loss at 3 billion miles and what levels the deep space dish receiving networks are dealing with?   Incredible that the data stream can be extracted from the noise. Mike  AC5P