My 2001 copy of Uplink-Downlink was printed by GPO and is 674 pages of 10-point type. I would not want to scan it! Anyway, it was only $25 from an Abebooks seller including tax and shipping and is in near-new condition including a plastic-wrapped dust jacket.
Jeremy On Mon, Jun 8, 2020 at 1:01 PM jimlux <jim...@earthlink.net> wrote: > On 6/5/20 3:43 PM, Wannes Sels wrote: > > I bought a used copy of Uplink-Downlink on Ebay. > > Unfortunately the quality is downright bad. Printed on what looks like > > bright white copy paper with a laser printer. > > All the images and illustrations are rasterized, the text is low > > resolution. The photo on the cover shows compression artifacts. > > The pdf on the NASA site is of similar quality, and probably what the > "print to order" version is printed from. > > I don't know where one would go about getting a copy of the GPO printed > version - perhaps a used book dealer. > Conceivably, someone could get a good copy from a library that happens > to have it and spend the time to scan it. > > > > > > > > The last page reveals the culprit: "Printed in Great Britain by > Amazon.co.uk > > " > > A quick search shows similar experiences with other print on demand books > > from Amazon. > > > > Unfortunately there's no way to tell if a book was printed on demand, > most > > listings just show the cover image instead of a photo of the actual book. > > > > I will try to return it, if I don't have to cover shipping costs. > > > > Buyer beware... > > > > Wannes > > > > On Mon, May 25, 2020 at 4:46 PM EB4APL <eb4...@gmail.com> wrote: > > > >> Hi Jim, > >> > >> This explains a lot of things. As an old time user of the Moon Bounce > >> time synchronization in the Madrid Space Complex, I can say that the > >> system was never popular among the users, it was cumbersome to use and > >> there were already other systems with better accuracy and availability, > >> such as VLBI and Loran-C. We used Loran-C as our daily reference > >> because we had a station at a distance of 650 Km and the signal was very > >> good, even with an old receiver who needed manual estimation of the > >> delay the results were very good. Maybe the aliens who designed the > >> system were not very aware of the humans idiosyncrasies > >> > >> I think that the idea was good, but the implementation was not so good. > >> I can summarize the "peculiarities" as I remember them: > >> > >> - The transmissions had to be scheduled for a period of common moon > >> view. The receiving station was manned 7/24 but the transmitting station > >> (DSS13, if I remember it correctly) had to be manned specially for the > >> event by a crew probably from Barstow, some 40 miles away. > >> > >> - Normally there were not provisions for voice communications between > >> the two end points, so if we did not got correlations we didn't know if > >> the transmitting station was working ok or even if it was not manned due > >> to some problem. > >> > >> - There were not monitoring aids in the receiver, so if we did not have > >> correlations, we has to climb to the roof, verify the pointing of the > >> antenna (there were a rifle scope for that), and if it was, tried to > >> contact DSS13 by phone and pray. > >> > >> - As you can figure it out, the antenna was not remotely controlled. One > >> had to climb to the roof, set the moon declination for that day using a > >> handwheel, slew the hour angle with a switch and select the hour angle > >> rate with another switch. The moon position and rate was obtained from a > >> nautical almanac and when the sky was clear we used the above mentioned > >> rifle scope. > >> > >> The receiver was quite dumb, all intelligence was on the transmitter > >> site. The TX equipment generated a PN code that lasted about 1s, and a > >> full observation cycle lasted about a minute, I don't remember the exact > >> figures. The code was sent advanced to take care of the round trip light > >> time but an additional time bias of 30 us was also introduced which was > >> the basis of the measurement. The bias was decreased 1us/s, so > >> theoretically it was received just on time in the second 30. > >> > >> The receiver generated the same PN using the station timing reference > >> (from a HP 5065A Rb) and it was correlated with the received code. The > >> output of the correlator was integrated and sent to a strip chart > >> recorder. The graph consisted in one trace with a quite noisy ramp and > >> the other trace with 1PPS from the station reference. Now the weird > >> thing: after finishing an observation, we put the graph in a desk and > >> using a drafting rule we draw a straight line that tried to be the "best > >> fit" to the noisy ramp. Were the line crossed the zero we read the PPS > >> mark there and counting back to the start of the minute we got the PPS > >> offset with respect to the transmitting station. Of course we averaged > >> the values obtained from several minutes, after discarding the noisiest > >> ones. > >> > >> Since we didn't had any faith in the system we didn't tried to suggest > >> improvements or improve it ourselves. A good one could be to use a > >> computer program to perform the best fit analytically, but this would > >> mean to type the hundreds of points manually from the graph and we never > >> tried this. There were not a digital version of the output, we also > >> could use a digital voltmeter for acquiring it. We suggested or > >> implemented a lot of improvements to other operational things, but this > >> contraption was felt as a dead horse from the beginning and its > >> operational life was short. Later it was replaced with a GPS based one: > >> 2 full height racks filled with equipment and an antenna made from a 10 > >> or 20 gallon hermetic paint drum for housing the front end electronics, > >> topped with a fiberglass radome about 1 1/2 ' in diameter. It was > >> painted white, but the cylinder origin was discovered during a > >> maintenance. It was a beautiful prototype that worked very well during > >> its shot life. > >> > >> I don't keep pictures of this equipment, but I have one with the same > >> antenna used for other purposes. > >> > >> Sorry for the bandwidth, but the thread brought me old memories. > >> > >> Best regards, > >> > >> Ignacio > >> > >> > >> El 23/05/2020 a las 19:17, jimlux escribió: > >>> On 5/23/20 9:18 AM, Mike Millen wrote: > >>>> Probably a good idea... there are two page 19s and no page 20 in the > >>>> pdf. :-( > >>>> > >>> > >>> > >>> That's the page where the aliens came and told us how to build the > >>> DSN, then the story resumes with 26m antenna design and operation. > >>> > >>> (If anyone's interested, I can probably ask the librarians to find it > >>> at JPL - correcting the pdf/microfilm is probably beyond scope) > >>> > >>> > >> > >> -- > >> El software de antivirus Avast ha analizado este correo electrónico en > >> busca de virus. > >> https://www.avast.com/antivirus > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.