Notes from South Pole TDRSS Relay (SPTR) Mtg/Telcon held on 1/6/98 Participants: GSFC (450, Eng Team, NISN) SP User Rep at GSFC (Troy Ames) MSFC (Kevin Takada) WSC (Jim Edgington, Bob Gonzales) SPTR OPERATIONAL USE - SPTR IMPLEMENTATION IS TO THE POINT WHERE ITS CONSIDERED OPERATIONAL AS OF JANUARY 5TH 1998 - ALL SP USERS ARE ENCOURAGED TO USE THE COMMUNICATIONS DURING SPTR SCHEDULED PERIODS AND LET US KNOW IF THEY ARE HAVING ANY PROBLEMS (IT AIN'T PERFECT JUST YET, BUT WE'RE GET'N CLOSER) - ALSO LET US KNOW YOUR SUCCESSES AS WELL! NISN/MSFC ITEMS - MSFC (Kevin Takada) reported there is a CISCO router S/W bug related to redistribution of routes (BGP protocol) that affects all SPTR routers (SP/WSC) being used. MSFC/AMES (NSI) is working with CISCO to demonstrate/isolate/resolve the problem. Work around router configurations have been put in place in the interim. There is still router tweaking going one as problems are reported. The following are the know problem areas remaining. -- Asymmetrical routing is currently being done at the SP during co-ops (TDRS/GOES). This results, on occasion, in SP return IP traffic being routed via GOES even though TDRS is handling the traffic transmitted to the SP (SSAF). A SP GINKO router change needs to be implemented once Chris Liljenstolpe returns to McMurdo on 1/8. -- During TDRS only mode of operation, there can be no e-mail traffic to/from the ATSVAX at Malabar. This can only be resolved by implementing "policy" routing. It is intending to implement policy routing once the T1 circuit is in to Malabar and the CISCO 4700 routers have been installed at both UofM and Malabar. Paul Eden is requested to e-mail the sptr collective to advise us when the T1 and 4700's has been installed. - MSFC (Kevin Takada) reported there is a potential Intra-Facility Link (IFL) problem between STGT and WSGT at WSC that may preclude using WSGT for F1 SPTR operations after the handover to WSGT on February 1st (post Shuttle WOW). It was intended to use fiber optic modem transceivers on the fiber IFL but there may be an RS422 compatibility issue. MSFC has ordered 3 Ethernet modems (single mode transceivers) to span the 6Km distance. Kevin was unsure of the priority and ETRO expected on these modems. GSFC (NISN-Stan Rubin) will check if any can be obtained elsewhere.(Late news - StanR indicates that he has located 2 xceivers & will be shipped as loaners - see below). The second WSC SPTR router (being integrated into the second TDI at GSFC) will be sent to WSC ASAP to test the current F/O modems for compatibility. WSC (Jim Edgington) will also see if other alternative transceiver interface equipment might be available that could be tested and used until the ordered E/N modems can be installed. NOTE-POST MEETING - GSFC (NISN) has located two 10-Base-T xceivers here at GSFC and will ship these to WSC on 1/9 for temporary use. They should arrive at WSC on 1/14 (Wednesday). SPTR ENGINEERING STATUS - WSC (Bob Gonzales) reported monitoring of the K-Band frequency indicates a fairly consistent frequency 12-15 KHz higher that nominally scheduled. Bob will advise Tri Thai after further data reduction the best frequency to have implemented within the SPTR SHO. WSC will FAX to Dave Israel the SSAR signal strength (Eb/No) info for further S-Band fade evaluation. - Miteq is building another S-Band LNA to be sent to the SP in a week to 10 days. A temporary LNA (spare GOES LNA) is currently being use at the SP to allow the SSAF link to work. Getting the LNA swapped-out will be addressed once the Miteq LNA is at the SP. Its anticipated the last flight into the SP will occur 1st week in February. - New K-Band encoder chips are being fabricated by ATSC. Tests will be scheduled within the next two week using the RFSOC/F1/WSC to check compatibility before shipment to SP. The KSAR file transfers are being used in an uncoded configuration with Bi-Phase-L modulation. A new SHO config code (P03) was fabricated to support this link configuration. EIRP margins are consider good to run uncoded and very few transmission errors in the transfer process have been observed thus far. - New SPTR MCS S/W has been FTP'ed and installed at SP to resolve interface problems with the SP fileserver. This appears to be working now but will be under close observation to assess possible slowdown's that have occurred. - The backup K-Band TWTA (#2) has a bad Standby status indication which precludes its current automatic use (turn-on) via MCS S/W control. A request will be made to swap the cables between TWTA's to isolate a possible cable problem. If not, it may be possible to modify the MCS S/W to better control its turn-on. This particular TWTA has an existing HV timer problem that must be observed for proper warm up, in the event its needed. TWTA-1 is configured as the prime right now and is working fine. - Dave I. is formulating and will be adding soon a "Frequently Ask Questions" (FAQ) feature to the SPTR Web page to dispel any misunderstandings that may have been derived from some of the recent email traffic on just what to expect from SPTR. SPTR OPERATIONS - The SPTR schedule has been modified to add the daily time of maximum elevation angle for SPTR support. The initial S-Band signal strength (fading) data taken thus far has indicated that good solid IP communications can be obtained plus/minus 1 hour about this max elevation time. The 45 minutes prior (and 45 mins after) this "prime" SPTR 2-hour window will be intermittent (3-10 minute) signal fades but is certainly usable for most IP traffic activity. Currently, the comm support phasing between TDRS and GOES allows continuous comm during the later portion of the TDRS view period/fades, when GOES is also available. Dave I. will add a graphic representation of a typical TDRS comm contact on the SPTR web page to illustrate/explain the usable period(s) for communications. - Andre F. has reported via email a problem with the methodology used on the K-Band file transfers which precludes transferring files onto the SP fileserver, during a TDRS contact, while the SP fileserver is transmitting files to the WSC fileserver. Its a matter of SPFS loading/processing speed to keep the data moving at a 2MB rate via the TDRS link. Until this is resolved (or an appropriate work around is developed), users are requested to place their files on the SPFS during periods other that when TDRS is scheduled. - A TDRS-1 E/W maneuver was performed on 6 Jan as it approached one end of its mandatory position box. Future E/W maneuvers will occur on 55-58 day cycles to maintain TDRS-1 within plus/minus 0.3 degrees centered at 49.0W (311.0E) longitude. SPTR signal strengths will be monitored closely for the next 3-4 months to ensure optimum SP SPTR antenna pointing was obtained. - The SPTR OIP document is through CCB now and has been made available on the SPTR web page (new items area). DCN-001, reflecting as-built, should be completed by 1/9 and will be incorporated within the OIP and place on the SPTR web page as soon as its completed.