SATELLITE ACCESS. Derived from AN/TSC-167(V) Satellite Transportable Terminal (STT) HANDS-ON TRAINING PROGRAM

Transcription

1 SATELLITE ACCESS Derived from AN/TSC-167(V) Satellite Transportable Terminal (STT) HANDS-ON TRAINING PROGRAM If your terminal has both a TDMA or a FDMA link, only one procedure is required. Once the satellite is accessed, bring the other modem online and verify its performance. There are separate procedures for accessing the satellite with a TDMA and a FDMA modem. Contact the satellite controller and give them the following: Name Organization Carrier ID Number Request permission to access the satellite with an unmodulated carrier. (CW) Change the A2A1, TDMA, modem output from modulated to a CW spike. In Hyper Terminal, at the prompt type: cw freq (frequency in hertz of L-band output from cut sheet) -power -30 To calculate Linkway output, Uplink frequency BUC LO = L-band center frequency. Uplink frequency = L-band center frequency. Ex. cw -freq power -30. will give you a uplink cw of 14.2 GHz at -30 dbm Upon controller approval put the HPA in transmit: At the A1A4, HPA Controller, Control Screen set the following: Mode: XMIT Adjust power per operator s instructions. Example: At the prompt type: cw -power -20

2 This will raise the power 10 db as 20 dbm is 10 db greater than 30 dbm. Peak and pol antenna per the satellite operator s instructions. When the satellite operator is satisfied: At Hyper Terminal Prompt: type hw, and <Enter> modem will reboot transmitting the normal modulated carrier. TDMA modem will: receive synch, indicated by a blinking SAT Light. transmit synch, indicated by a solid SAT Light. Verify A2A1 TDMA Modem Performance The following steps should be performed upon entrance into the TDMA network and then daily as part of routine maintenance. CLEAR BURST At Hyper Terminal Prompt: type cb, press <Enter>. The clear burst command will erase all burst statistics. RECEIVE BURST TIME PLAN At Hyper Terminal Prompt type rbtp, press <Enter>. Displays receive burst time plan of the modem. RBTP Status Fields List the ID, type, transmit and receive terminals, and all other relative carrier information. RECEIVE STATUS At Hyper Terminal Prompt type rx, press <Enter>. Displays receive status of the modem. Powerful tool for maintenance and troubleshooting. Allows user to identify bursts ID between terminals. Receive Status Fields State RxSynced TT modem has locked on to the reference burst. Search TT modem has not locked on to the reference burst. If the modem stays in this state for several minutes verify the MRT is transmitting and there are no local downlink problems.

3 RefBurstRawBer BER of the modem pre FEC. Should be 10E-3 or better. If below indicates a problem that will have to be isolated. Rxatten Value of the modems internal attenuator setting, range of Optimal setting is 20. If setting is near or at maximum, attenuation may have to be added to the receive chain. If setting is near or at minimum, power may have to be added at the MRT, or attenuation taken out of the MRT transmit chain. REFERENCE BURST At Hyper Terminal Prompt type rb, press <Enter>. Displays reference burst statistics of the modem. Reference Burst Status Fields Burst ID 1, the MRT reference burst is the most important burst. TT will not remain in the network without the reference burst. Detects Number of times the modem has detected, or received the RB. Number should be steadily increasing. Misses Number of times the modem has NOT received the RB. Number should be very small, if the number continues to increase, the problem will have to be isolated. VitCorrs Number of Viterbi corrections performed by the modem. Should be low, but some will always be present, compare over 24 hour window to baseline system. If the number is increasing rapidly, indicates a problem that will have to be isolated. FrEr Frequency Error in Hertz. Within +/- 100 Hertz If not, contact customer service. Modem will have to be replaced with a known good modem. Power Receive power in db s. Range +6 to -6 Should be within.5 of 0, 0 = - 55 dbm. If -6 power is too low, if +6 power is to high. Troubleshoot to isolate and correct the problem. RSCorrs Number of Reed-Solomon corrections. Should be low, 10 to 20 per day maximum. A higher number indicates a degrading system and the problem needs corrected.

4 CRCErrs Number of uncorrectable errors. Steady/rapid increase indicates a poor RF link. Link failure is highly probable, the problem needs correction as soon as possible. SHOW BER At Hyper Terminal Prompt type show_ber, press <Enter>. Displays raw BER statistics of the modem. Show_BER Status Fields Bits Number of bits encountered, will increase over time. BitErrors Number of bit errors received. Will increase over time. BER Raw Bit Error Rate. Should be 10E-3 or better. If below indicates a problem that will have to be isolated. TRANSMIT FIELDS At Hyper Terminal Prompt type tx, press <Enter>. Displays transmit statistics of the modem. Transmit Status Fields State TxSynced TT modem has transmitted 3 consecutive AB s at the correct time. Search TT modem has not transmitted 3 consecutive AB s at the correct time. If the modem stays in this state for several minutes verify the MRT is transmitting and there are no local downlink problems. Ping from Modem to Modem At Hyper Terminal Prompt type: ping xx.xx.xx.xx -i 0 -t 4000 ping (IP address of modem you are reaching), -i = Interface 0, and t, time 4000 ms. Because of the bursty nature of the TDMA modem, ping must be held-up for a period of time to ensure a burst catches it. TxSyncLosts Total number of times modem has lost transmit synch. Should be at or near 0. A steadily increasing value indicates a system problem that needs to be isolated and corrected.

5 Access the Satellite for FDMA At the A2A6, navigate to the MOD/IF menu: turn transmit ON. Contact the satellite controller, provide the following: Name Organization Carrier ID Number Request permission to access the satellite with an un-modulated carrier.(cw) Upon controller approval: Put HPA in transmit: At the A1A4, HPA Controller, Control Screen set the following: Mode: XMIT At the A2A6, FDMA Modem: navigate to the MOD/IF menu Transmit Power Screen. Following the controller s direction: raise and lower transmit power. Peak and Poll the antenna per the controller s instructions. When the controller is satisfied, navigate to the A2A6 TEST/CARRIER menu and set the CARRIER TO NORMAL. At the A2A6 verify the following: MOD Transmit ON LED: illuminated DEMOD SIGNAL LOCK LED: illuminated