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Hi Fred, First, let me apologize for the tardiness of my reply. I just returned from travels where my access to the Internet was sporadic... > The GOES-South data is consistently missing from 07:15 until 11:45 UTC. > The GOES-10 data sets from NESDIS do not show this data outage. The > GOES-10 orbit is degrading, so the satellite position in the sky makes a > figure 8 in the sky. If the antenna beam width is less than the figure > 8 pattern in the sky, the satellite will go outside the antenna beam, > causing data loss. This appears to be happening with the GOES-10 data > from GOES-South. Yes, our GOES-10 ingest capability does not yet include tracking. We have been investigating an affordable solution to this problem for the past two months. We should be working on an implementation for a single axis "tracking" (vertical only) in the next few weeks. > If the antenna was exactly centered on the figure 8 > and the figure 8 was bigger than the antenna beam width, data would be > lost twice per day. If the antenna is not centered, data will be lost > just once per day. This is what appears to be happening. The dish receiving the GOES-10 data rebroadcast through GOES-12 is also a fixed mount. > Was this > antenna misalignment done on purpose to insure data delivery in the > middle of the day, or was it inadvertent and could be corrected with a > simple repositioning of the antenna? The dish was pointed at the equatorial crossing position of the satellite to maximize the daily coverage. Since GOES-10's orbital inclination is now approx 2.25 degrees, a fixed mount will no longer be able to get all of the data all of the time. > Back in the early 90's GOES-7 was the only remaining US geostationary > satellite, and it had run out of fuel for station keeping. The figure 8 > pattern grew until it exceeded the beam width of the antenna at the > NSSFC where I was at the time. Our GOES antenna was not a tracking > antenna, but it did have electric motors for positioning the antenna. I > worked with one of our electronic technicians to develop an automated > antenna moving process. I provided him with an formula of figure 8 > growth with time. He then wrote a simple program to convert this figure > 8 into the number of pulses needed to move the antenna motors. He also > build a D/A converter to convert the digital pulses into electric pulses > for the motors. This "tracker" arrangement worked quite nicely until > GOES-8 was launched in 1994 and the "geostationary" satellites when back > to being geostationary. This is very interesting indeed. The GOES-10 dish being used at the moment is, unfortunately fixed. The GOES-12 and GOES-11 dishes do have elevation controls and so could be used in the manner that you used while at NSSFC. Do you still have the position calculation software around? I have been thinking about writing the same kind of software so that we could position the GOES-10 dish after motorization. In fact, there is a meeting today among RAL, EOL, and Unidata to discuss where what should be done to improve the ingest of all three GOES platforms at UCAR. I can let you know the outcome of the meeting if you are interested. Thanks for the note, it was very useful. Cheers, Tom **************************************************************************** Unidata User Support UCAR Unidata Program (303) 497-8642 P.O. Box 3000 address@hidden Boulder, CO 80307 ---------------------------------------------------------------------------- Unidata HomePage http://www.unidata.ucar.edu **************************************************************************** Ticket Details =================== Ticket ID: QKJ-646440 Department: Support McIDAS Priority: Normal Status: Closed