QRP signals from Pathfinder probe (off topic)
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QRP signals from Pathfinder probe (off topic)
 
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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 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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some discussion including calculation of losses around 147db here:
https://www.reddit.com/r/amateurradio/comments/3d93en/the_radio_signal_from_the_new_horizons_spacecraft/ scott [hidden email] On Thu, Jul 16, 2015 at 1:10 PM, <[hidden email]> wrote: > 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 > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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In reply to this post by Mike Maloney
Well, at least they have big antennas. ;) I read the other day on the NOVA
website that New Horizons will be downloading the data acquired in the flyby at a data rate of only 1 kb/s - think "1200 baud modem" for those of you old enough to remember them. And there was another fascinating article there about how they use Reed-Solomon error correcting codes to compensate for the inevitable bit errors and reduce the need for retransmission (and now using the same RS code for DNA data storage, very cool stuff.) Nothing about the path loss, but knowing the data rate is so low, and that the RS code is probably good for a considerable error burst of several bits, that should at least give you a sense of what the loss might be! 73 jeff wk6i On Thu, Jul 16, 2015 at 11:10 AM, <[hidden email]> wrote: > 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 > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] -- Jeff Stai ~ [hidden email] Twisted Oak Winery ~ http://www.twistedoak.com/ Facebook ~ http://www.facebook.com/twistedoak ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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I decided to spend a minute googling, here's a paper with a lot of cool
tech details: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.466.3341&rep=rep1&type=pdf 73 jeff wk6i On Thu, Jul 16, 2015 at 11:31 AM, Jeff Stai <[hidden email]> wrote: > Well, at least they have big antennas. ;) I read the other day on the NOVA > website that New Horizons will be downloading the data acquired in the > flyby at a data rate of only 1 kb/s - think "1200 baud modem" for those of > you old enough to remember them. And there was another fascinating article > there about how they use Reed-Solomon error correcting codes to compensate > for the inevitable bit errors and reduce the need for retransmission (and > now using the same RS code for DNA data storage, very cool stuff.) > > Nothing about the path loss, but knowing the data rate is so low, and that > the RS code is probably good for a considerable error burst of several > bits, that should at least give you a sense of what the loss might be! > > 73 jeff wk6i > > On Thu, Jul 16, 2015 at 11:10 AM, <[hidden email]> wrote: > >> 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 >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > > > -- > Jeff Stai ~ [hidden email] > Twisted Oak Winery ~ http://www.twistedoak.com/ > Facebook ~ http://www.facebook.com/twistedoak > -- Jeff Stai ~ [hidden email] Twisted Oak Winery ~ http://www.twistedoak.com/ Facebook ~ http://www.facebook.com/twistedoak ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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In reply to this post by Mike Maloney
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:[hidden email]] On Behalf Of [hidden email] 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 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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In reply to this post by jeff stai-2
Here's another paper that details the RF side of things. They needed an Ultra-Stable Oscillator, as well :-)
http://www.boulder.swri.edu/~tcase/NH%20RF%20Telecom%20Sys%20ID1369%20FINAL_Deboy.pdf -Brian N9ADG ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Scott Simpson
It would seem that the DX record is held by the Voygers which long ago
left the solar system. I don't know their power but they still check in from way beyond Pluto. So NewHorizons is DX but not real DX YET. 73 de Brian/K3KO On 7/16/2015 18:31 PM, Scott Simpson wrote: > some discussion including calculation of losses around 147db here: > > https://www.reddit.com/r/amateurradio/comments/3d93en/the_radio_signal_from_the_new_horizons_spacecraft/ > > > > > scott > [hidden email] > > On Thu, Jul 16, 2015 at 1:10 PM, <[hidden email]> wrote: > >> 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 >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2015.0.6081 / Virus Database: 4392/10243 - Release Date: 07/16/15 > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Mike Maloney
Voyager is still going strong many times further away than Pluto, 315w to a
3.7m dish. from over 19 billion KM. <[hidden email]> wrote: > 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 > ______________________________________________________________ Elecraft > mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: > http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html Message delivered to > [hidden email] > -- Brian Duffell G3VGZ Yarm England ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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In reply to this post by Mike Maloney
Uhuh - and how many of you have worked such DX?<smile>
The signal level seen on earth is 4E-19 or -196 dBw (subtract 30-dB to yield -166 dBm). The path loss at Pluto (31.9AU) is without including antenna gain 303.5 dB. Interesting that I read they plan to run 600bps at 36AU. Other numbers of interest is downlink f=8.438 GHz, downlink antenna (2.1m dish) gain is +42 dB and Tx power is 12-15w (say +41 dBm); spacecraft EIRP = 42+41 = +83 dBm. -303.5+83 = -220.5 dBm. Add gain of ground antenna +73 dBi (70m dish): -220.5+73 = -146.5 dBm Your K3 MDS is -145 dBm at B=500 Hz Just for grins I substituted my dish (4.9m) with gain 49.7 dBi and signal to my Rx would be -220.5+49.7 = -170.8 dBm If I use a really narrow bandwidth I might see a signal trace using something like spectravue sw. A ham has received Pioneer's signal in such a manner when it was beyond Pluto's orbit. It was not easy! 73, Ed - KL7UW ----------------------------------------------- From: brian <[hidden email]> To: [hidden email] Subject: Re: [Elecraft] QRP signals from Pathfinder probe (off topic) Message-ID: <[hidden email]> Content-Type: text/plain; charset=windows-1252; format=flowed It would seem that the DX record is held by the Voygers which long ago left the solar system. I don't know their power but they still check in from way beyond Pluto. So NewHorizons is DX but not real DX YET. 73 de Brian/K3KO On 7/16/2015 18:31 PM, Scott Simpson wrote: > some discussion including calculation of losses around 147db here: > > https://www.reddit.com/r/amateurradio/comments/3d93en/the_radio_signal_from_the_new_horizons_spacecraft/ 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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On Thu, Jul 16, 2015 at 4:33 PM, Edward R Cole <[hidden email]> wrote:
> .... = -146.5 dBm > ============= Very good, Ed, thanks. I'm sure they use some sort of FEC encoding like that of the JT software. If I understand that correctly, such a signal can be decoded if it's a couple of s-units, say 10 db, below the noise level. So with their ultra-low-noise gadgetry they should be able to hear it for several million more miles.....? Tony KT0NY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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Here is details on spacecraft design and on the RF comms subsystem. Interesting reading
http://www.boulder.swri.edu/pkb/ssr/ssr-fountain.pdf The New Horizons Spacecraft - Johns Hopkins Applied Physics Laboratory http://www.boulder.swri.edu/~tcase/NH%20RF%20Telecom%20Sys%20ID1369%20FINAL_Deboy.pdf The RF Telecommunications System for the New Horizons Mission to Pluto - Johns Hopkins Applied Physics Laboratory 73 Rick AG6AY |
Re: QRP signals from Pathfinder probe (off topic)
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OK, with the Path loss considered, and the comm link budget in the mix, with proper freq stabilization, could the K series integrate any possible down converted channel to a discernible signal?
If not, then the topic is mute, Sorry, better things to consider......IMHO Mel, K6KBE From: "[hidden email]" <[hidden email]> To: [hidden email] Sent: Thursday, July 16, 2015 3:35 PM Subject: Re: [Elecraft] QRP signals from Pathfinder probe (off topic) Here is details on spacecraft design and on the RF comms subsystem. Interesting reading http://www.boulder.swri.edu/pkb/ssr/ssr-fountain.pdf The New Horizons Spacecraft - Johns Hopkins Applied Physics Laboratory http://www.boulder.swri.edu/~tcase/NH%20RF%20Telecom%20Sys%20ID1369%20FINAL_Deboy.pdf The RF Telecommunications System for the New Horizons Mission to Pluto - Johns Hopkins Applied Physics Laboratory 73 Rick AG6AY -- View this message in context: http://elecraft.365791.n2.nabble.com/QRP-signals-from-Pathfinder-probe-off-topic-tp7604967p7604995.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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Certainly, with a proper transverter (or down converter) and adequate
receive antennas, the K3 could serve as a suitable IF. The decode of the received data is quite another matter. Will anyone do that with their K3, I don't know, but the K3 is capable enough given an adequate down converter. One would likely need a stable frequency reference, and the K3 has the option for an external reference. 73, Don W3FPR On 7/16/2015 7:16 PM, Mel Farrer via Elecraft wrote: > OK, with the Path loss considered, and the comm link budget in the mix, with proper freq stabilization, could the K series integrate any possible down converted channel to a discernible signal? > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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In reply to this post by Brian D
315w exceeds the total power budget for the Voyager 1 spacecraft, which
is currently 254.6 watts. The only reference to the transmitter power I can find suggests that it is 20 watts. The 315 is probably EIRP, but that is not what was being quoted for the Pluto probe. They both seem to have the same actual PA output power. So at over 36 hours round trip light travel time (0.002 light years range), Voyager 1 scores a lot more points compared with less than 9 hours for the Pluto probe which has the same power, but with 12dB less free space path loss. -- David Woolley Owner K2 06123 On 16/07/15 20:46, Brian D wrote: > Voyager is still going strong many times further away than Pluto, 315w to a > 3.7m dish. from over 19 billion KM. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: QRP signals from Pathfinder probe (off topic)
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In reply to this post by Fred Townsend-2
Lets not forget to include Madrid (Spain) and Canberra (Australia) in the
above story, without them Goldstone cant do it on it's own. One station may start the transmission, but every 8-12hrs each station seamlessly hands over to the next to provide continuous coverage at the earth rotates. It's even more important for Voyager with a transmission path of 18 hours, now that is mind blowing stuff. 73 Matthew VK5ZM On 17 July 2015 at 04:28, Fred Townsend <[hidden email]> wrote: > 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 > <SNIP> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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