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#1
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Apollo Lunar Surface Communications Requirements
Does anyone know how many communications circuits the large deployable
parabolic antenna could manage? There were voice, telemetry and video circuits, but how many of each? |
#2
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Apollo Lunar Surface Communications Requirements
On Apr 14, 4:14*am, Alan Erskine wrote:
Does anyone know how many communications circuits the large deployable parabolic antenna could manage? *There were voice, telemetry and video circuits, but how many of each? According to SETI, all sorts of communications (regardless of frequency) can efficiently go to/from Earth, especially to/from that extremely nearby moon, so I'd imagine those fancy NASA/Apollo microwave antennas could manage as much bandwidth as anything we could muster at that time. Of course nowadays a compact, light weight and very energy efficient laser communications beam would be just the ticket, with a focus of roughly 2 km diameter if that were necessary. Otherwise a wider laser beam communicator of something like a hand held cellphone or satellite- phone would be more than sufficient for delivering an extremely wide bandwidth and terrific data throughput. http://groups.google.com/groups/search http://translate.google.com/# Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet” |
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Apollo Lunar Surface Communications Requirements
On Apr 14, 4:14*am, Alan Erskine wrote:
Does anyone know how many communications circuits the large deployable parabolic antenna could manage? *There were voice, telemetry and video circuits, but how many of each? According to SETI, all sorts of communications (regardless of frequency) can efficiently go to/from Earth, especially to/from that extremely nearby moon, so I'd imagine those fancy NASA/Apollo microwave antennas could manage as much bandwidth as anything we could muster at that time, with very little loss of signal considering the to/from path being perfectly clear. Actually, the vast majority or terrestrial RF/EMF doesn't get outside of our atmosphere, or at least not much past LEO unless it's of microwaves and being directed or focused sufficiently, of which most terrestrial microwaves are not. Of course nowadays a compact, light weight and very energy efficient laser communication beam would be just the ticket, with a focus of roughly 2 km diameter at 384,000 km if that distance were necessary. Otherwise a little wider laser beam communicator of something like a hand held cellphone or satellite-phone configuration would be more than sufficient for delivering an extremely wide bandwidth and terrific data throughput once the extremely narrow channel is established. However, a tightly focused laser cannon method deployed in LEO could get that intended target area down to a couple meters diameter for that same 384,000 km distance. Now that's efficient communications. http://groups.google.com/groups/search http://translate.google.com/# Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet” |
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Apollo Lunar Surface Communications Requirements
On 29/04/2012 10:46 AM, Obviousman wrote:
On 14/04/2012 21:14, Alan Erskine wrote: Does anyone know how many communications circuits the large deployable parabolic antenna could manage? There were voice, telemetry and video circuits, but how many of each? The S-Band carried: Voice BioMed Data EMU PCM Telemetry Emergency Keying TV Reading through the technical notes, it seemed there were radios (TX/RX1, TX/RX2) and they operated on 2282.5 MHz for transmission, and 2101.8 MHz for reception. Looks like there were five circuits: Primary TX Primary RX Voice Backup Emergency Key TV (FM) I've attached some detail which may help. Good man; thank you! That goes a long way to answering my questions and helps me with my own concept. Thank you very much. Where did you find this? |
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Apollo Lunar Surface Communications Requirements
From NASA Technical Note TN D-6974 Apollo Experience Report - Lunar
Module Communication System available for download free from the NASA Technical Reports Server (NTRS): http://ntrs.nasa.gov/search.jsp Direct download of that file: http://hdl.handle.net/2060/19720023255 On 2/05/2012 13:16, Alan Erskine wrote: On 29/04/2012 10:46 AM, Obviousman wrote: On 14/04/2012 21:14, Alan Erskine wrote: Does anyone know how many communications circuits the large deployable parabolic antenna could manage? There were voice, telemetry and video circuits, but how many of each? The S-Band carried: Voice BioMed Data EMU PCM Telemetry Emergency Keying TV Reading through the technical notes, it seemed there were radios (TX/RX1, TX/RX2) and they operated on 2282.5 MHz for transmission, and 2101.8 MHz for reception. Looks like there were five circuits: Primary TX Primary RX Voice Backup Emergency Key TV (FM) I've attached some detail which may help. Good man; thank you! That goes a long way to answering my questions and helps me with my own concept. Thank you very much. Where did you find this? |
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Apollo Lunar Surface Communications Requirements
On 2/05/2012 4:01 PM, Obviousman wrote:
From NASA Technical Note TN D-6974 Apollo Experience Report - Lunar Module Communication System available for download free from the NASA Technical Reports Server (NTRS): http://ntrs.nasa.gov/search.jsp Direct download of that file: http://hdl.handle.net/2060/19720023255 Your nickname holds true - I already had the report. I'm such a dill. ;-] Thanks for that. |
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Apollo Lunar Surface Communications Requirements
Obviousman writes:
From NASA Technical Note TN D-6974 Apollo Experience Report - Lunar Module Communication System available for download free from the NASA Technical Reports Server (NTRS): I still don't know why the VHF comm systems were AM, not FM/PM. Why would they have chosen to have to have modulators & such rather than use alternatives? -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
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Apollo Lunar Surface Communications Requirements
David Lesher wrote:
I still don't know why the VHF comm systems were AM, not FM/PM. Why would they have chosen to have to have modulators & such rather than use alternatives? Isn't AM dead simple compared to FM? Less complexity means less to go wrong, and probably less weight, too. |
#9
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Apollo Lunar Surface Communications Requirements
Philip Lantz writes:
I still don't know why the VHF comm systems were AM, not FM/PM. Why would they have chosen to have to have modulators & such rather than use alternatives? Isn't AM dead simple compared to FM? Less complexity means less to go wrong, and probably less weight, too. It's the other way around. FM/PM modulators are super simple; amplifer stages after that can be Class C, not A or AB1. M needs modulation applied the output stage, more power needed to do that. -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
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