[time-nuts] time sync by moonbounce

Mon Jun 8 16:47:28 UTC 2020

I also bought my copy of "Uplink-Downlink" through Amazon but  had better
luck.  The cover photo is in color, not quite as sharp as I would have
preferred
but has no apparent compression artifacts.

The text inside is of good quality- nop complaints in this department.

However, the photos inside are of poor quality.  They are screen-printed,
with
the screen elements as big as basketballs, and in general any text within
the
photo-proper is completely unreadable.  But the captions are just fine.

I've been unable to find any publisher's info, just a note on the back
dustcover
stating "Made in the USA; Coppell, TX; 30 May 2020".  It arrived at my home
in Kerrville, TX three days later, so I presume that the copy was custom
printed
just for me.

Dana

On Mon, Jun 8, 2020 at 7:23 AM Wannes Sels <wannes.sels at gmail.com> 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 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 <eb4apl at 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
> >
> >
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