South Pole TDRSS Relay Joint NASA/ATSC Engineering Status As of 10/28/97 1. Highlight's A. Integration South Pole Subsystem - TWTA's The TWTA's are both installed now and working with the PLC. TWTA 1 is completely functional. TWTA 2 required bypassing the standby mode counter to get the unit to function. Parts from a third TWTA at BLT were used in an attempt to repair the failed circuit but the effort was not successful. The bypass is somewhat dangerous as the units need approximately three minutes to warm up from "Power On" to "Standby" mode and the bypass eliminates this. The danger is that in immediately going from "Power On" to "RF On" will probably damage the tube. In software a counter has been installed to ensure the three minute wait period is met. For local front panel operation, the TWTA has been marked with a warning sign. Testing with the TWTA's has also found differences in the output levels. The Logimetrics test data was checked and it was found that unit 2 has a lower output due to the installation of 3 options. Research on the options is in progress. The difference in output is 16 dB and was made up in testing at Logimetrics by providing a higher input level to TWTA 2. For SPTR purposes the theoretical input to the TWTA's was 0 dB, (+5 dB from the Modulator with approx 5 dB of loss through the power divider and cabling) which means pads will have to be used to attenuate the input from the theoretical 0 dB to the -7.5 dB that TWTA 1 wants. For unit 2, the input will be 0 dB versus the +7.5 dB that this unit wants. Additional power may be possible out of the Modulator, an additional 3 dB may be obtainable, to reduce the difference to approx. 4 dB. The net result will not be noticed at our initial first year rates, the margin at 2 Mbps is +12 dB and is +7.23 dB for 6 Mbps data. For 50 Mbps, the theoretical level on TWTA 2 is -1.98 dB so unit 1 will have to be used for the 50 Mbps testing. - Modulator/Encoder The Modulator and Encoder were partially tested with TDRSS last week and the testing performed was successful. However, all data rates were not checked out so additional testing is being scheduled. The implications have been discussed with R. Conrad and M. Czumak as the project needs some time with the units for local integration and testing if the 11/7 is expected to have a chance for success. M. Czumak has indicated that we can obtain the units later this week after a connector change is made. They will then pick up the units from the BLT SPTR Lab when their test is scheduled. - TDI The TDI was delivered last week to HB. Local testing is being done in HB. Attempting to set up testing at the BLT SPTR Lab where the scrambler/descrambler could be verified with the modem but there has been resistance to moving the unit to BLT. These issues will be worked this week but the delays may alter the projected shipping of the first rack next week. - Completed the custom HP switch cabling. - Completed the custom PLC and baseball switch cabling. - Received the documentation WSC Subsystem - Completed the DB37 end of the DB37/Twinax breakout cables (38). - Assembled and labeled the I/O panels. - Rack'n'stack in progress. The routers have no rack mount kit so mounting is being worked with shelves. B. EC(s) - Updated the cables runs list with "as built" information. C. Parts Nothing significant. Awaiting the Ku-Band antenna and the COTS cables ordered for the MCS. D. Testing Testing has been scheduled the evening of 11/7 for testing the SPTR Ku-Band system through TDRSS. Data to fulfill the actions placed on the project is being obtained from the SPTR webpage. An area of concern is the pedestal proposed for the test. From discussions this week it appears the Ku antenna will be put onto a pedestal that does not track. E. Pack & Ship The plans made for the breakdown and packing of the system are being re-evaluated and changed due to schedule changes. D. Rill will be down at BLT on 10/30 with a team to obtain information necessary to prefab the crates to minimize time delays when it is time to ship. 2. Software a. TWT interface complete (including 3 minute timer for tube warm up) b. Router interface complete c. Up/downconverter interface started - on hold until unit delivered. d. Started status logging function 3. Hardware Configuration Items HWCI 1. Awaiting delivery of the Ku-Band antenna. HWCI 2. Awaiting delivery of the Up/Downconverter. HWCI 3. Modulator testing is being rescheduled at the RF SOC. The Encoders will be retested at the same time. Integration issues are being worked around the test schedules. HWCI 6. TDI delivery is lagging. 4. Software Configuration Items Software orders are all complete. 5. Schedule Being evaluated day by day. 6. Medical Clearance A. Fortin has been approved and will depart the MD area on 11/24. K. Culin has been approved and will depart the MD area on 11/12 with a departure of 11/15 for NZ. H. O'Donnell has been approved and will depart the MD area on 11/15.