Notes from South Pole TDRSS Relay (SPTR) Mtg/Telcon held on 11/10/97

Participants:  GSFC (450, Eng Team)
               MSFC (Kevin Takada)
               Miteq (Steve Phillips)


NISN/MSFC ITEMS

- MSFC (Kevin Takada) reported the Malabar/NSI conversion is still not
entirely
completed yet. There are problems with users via AOL. The problems being
experienced may be due to the SP routers still using BBN IP addresses. This
is primarily being worked by UofM with Malabar and NSF (ASA) at this point.

- Kevin T. reported that the WSC cables are presently being fabricated for
the NSI (PSCN) interface. MSFC was advised that the SPTR TDI should be
shipped to WSC NLT 11/17.


ENGINEERING TEAM STATUS

- Refer to Kevin's Eng Status Report (11/10/97) for more details.

- ATSC reworked the TDI and its now working within the GSFC Test Bed.
Further verification is required with WSC to make sure of SSAR IR
compatibility.

- The TWTA differential in power out is about 8dB because of TWTA-2 input
drive circuitry being different. With all the integration optimization
complete now, when TWTA-1 is putting out 20 Watts, TWTA-1 will be able to
output about 8 Watts. Should TWTA-2 be used it should able to close a 10MB
coded link with no problem.  The TWTA's will be shipped in this
configuration.

- Andre F. has contacted AVTEC (Frank Ross) who has provided suggestions on
how best to improve the KSAR thruput rate on the fileserver transfers. This
is in work now. The SPFS BER pattern to allow WSC to perform BER
measurements has been tested successfully.

- We conferenced in Miteq (Steve Phillips) who provided the following
status update on the S-Band Upconverter/Downconverter.

       -- The Synthesizer should be received at AVTEC 11/14 for final
          integration.

       -- Best (promised) date for shipping UC/DC to GSFC is by 11/28.

       -- It is intended to check the UC/DC here at GSFC for
          functionality and SPTR MCS software interface compatibility.
          It will then be shipped (hand carried) ASAP to SP. The Eng
          Team will be flying to SP on Dec 6th (weather permitting)

       -- Frank S. will contact Wallops (Tome Gross) and Michael
          Comberiate at GSFC to see who may be able to hand carry
          the UC/DC to McMurdo/SP.


TESTING

- The final SPTR checkout scheduled for 11/7 (Friday) had to be cancelled
because of Wx in Maryland area which precluded safely mounting the 4ft
antennas onto the RFSOC antenna system. Weather finally cleared on 11/10
allowing the antennas to be mounted and collimated at RFSOC. A quick check
of the S-Band bore siting on TDRS-1 was successfully completed by COB 11/10.

- The final SPTR checkout has now been rescheduled for 11/11 (Tuesday).

NOTE: POST MEETING UPDATE...It Works! It works! Refer to Dave Israels email
(SPTR Test Results 11/11/97) for the details. SPTR equipment will be boxed
immediately for shipment to SP (minus the SB UC/DC). Many thanks to all
those involved in pulling this final checkout together...



Subject: SPTR Test Results 11/11/97

The SPTR equipment was successfully tested today through the TDRS-1 
satellite and is now on its way to be packed and shipped to the South Pole.  
The tests were performed at the Goddard RF Sim. Ops. Center (RFSOC).  The 
SPTR S and K band antennas were mounted to the RFSOC antenna and the two 
racks of SPTR equipment were powered up and connected while already inside 
the delivery truck.  All three links (K-Band Return, S-Band Forward, and 
S-Band Return) were verified.  The S-band up/downconverter has not been 
delivered yet, so it was replaced using test equipment.  The routers and 
fileserver have not been installed at White Sands yet, so no IP traffic or 
data files were transmitted.

Here are the results of the various tests:

1.  50 Mbps, uncoded, was transmitted error free through the K-band return, 
    using a BER transmitter as a data source.
2.  1 Mbps, coded, was transmitted error free through the K-band return, 
    using the SPFS as a BER data pattern data source.
3.  1.024 Mbps, coded, was transmitted on both the S-band forward and return 
    links.  The BER performance was 1E-7 or better on both links throughout 
    the testing.  The links should be better when the equipment is in its 
    final configuration with the real up/downconverters.
4.  White Sands was able to lock to a repeating frame sync pattern on the 
    S-band return.  This verified the SPTR satellite modem's TDRSS 
    compatibility.
5.  The SPTR software was able to automatically turn on the return signals 
    when the S-band forward link arrived.  This will allow for autonomous 
    operations.
6.  50 Mbps encoded was attempted but the convolutional encoder still does 
    not appear to work at rates above 10 Mbps.  (Only 1 Mbps, 10 Mbps, and 50 
    Mbps were tested today).
7.  Peak K-band return C/No was measured to be 94 dB-Hz.

Installation and testing at the Pole is scheduled to begin on December 6th.

Dave