1. 1 DCPR Power Ranges Proposed for CS v.2.0 DCS Manufacturers Meeting June 13, 2007 Peter Woolner Noblis pwoolner@noblis.org 703-610-1724

2. 2 Power Levels for CS v.2.0 The 2 dB ranges proposed at Asheville are not practical: a range of at least 4 dB will be necessary The satellite transponder functions best with the minimum possible EIRP range Wider range of EIRP must also result in higher minimum EIRP Higher EIRPs consume extra input power at the DCP location Assumes no CDMA during the transition

3. 3 Proposed EIRP ranges for system design: –300 bps: 37 dBmi to 41 dBmi –1200 bps: 43 dBmi to 47 dBmi Assumes reception at DRGS with 15 dB/K G/T and “worst case” transponder loading Other relevant factors: –Based on actual measured GOES-13 performance –Assumes DCP and DRGS at 5 degrees elevation Availability of power control would provide an additional significant margin of safety Recommended EIRP Ranges

4. 4 Reason for this Choice Basic Criterion: Under worst case conditions, the first v.2.0 DCP on GOES 13 must provide acceptable performance into a DRGS with a G/T of 15 dB “Worst case” is maximum GOES 11/12 loading, i.e. 112 channels at average EIRP of 48.7 dBmi, all the meeting v.1.0B EIRP requirements Proposed minimum EIRPs give Eb/No of 11.7 dB for these conditions I do not expect the worst case to actually occur but cannot quantify the improvement

5. 5 Assumed Transition Progression The proposed large reduction in EIRP is only viable if the transition is coordinated with the change to GOES N/O –GOES N/O has 14 dB more downlink EIRP Transition assumes “worst case” loading on GOES 11/12 to “worst case” on GOES 13 –GOES 11/12: 112 channels at 48.7 dBmi –GOES-13: 214 channels at 40.3 dBi Channels are changed from v.1.0B to v.2.0 and new channels are added at a fixed ratio

6. 6 Transition Rule Additional channels must not be added faster than old channels can be converted –E.g. change 10% of old channels to new CS (equals 11 channels) –Can then operate 10% of 210 (21 channels) at the CS v.2.0 EIRP levels Channels that were not used on GOES 11 or 12 (e.g. channels 1 and 100) can be counted as part of the “changed” channels Rule can be applied to whole channels or to specific time periods if the allocation process can handle the complexity

7. 7 Minimum EIRPs on GOES 13 Assumes “worst case” average uplink EIRP Includes 1 dB margin Minimum Uplink EIRP (dBmi) with Worst Case Transponder Loading, into 15 dB/K DRGS, at Stated Transition Stage Transition Stage0%10%20%30%40%50%60%70%80%90%100% For 300 bps DCPs38.037.837.537.337.136.836.536.235.935.535.2 For 1200 bps DCPs44.043.843.543.343.142.842.542.241.941.541.2

8. 8 Transition Options Early transitions to CS v.2.0 DCPs could reduce average EIRP on GOES 11/12 and decrease number of low EIRP transmitters Some CS v.1.0B DCPs could meet many v.2.0 requirements –EIRPs per v.1.0B are too high to count as v.2.0 –Timing, stability, ACI, etc. could make them “good neighbors” and remain in use for years –NOAA can monitor actual EIRPs relative to the pilot level and identify every DCP by address

9. 9 Early Change to v.2.0 Any DCP can be changed to a v.2.0 unit at any time after Wallops receivers are upgraded to comply with v.2.0 (DRGS upgrade?) –The extra channels must not be used until the new satellite is activated but the DCP can be fully v.2.0 compliant with EIRP the only potential problem All EIRPs mentioned herein will work OK into Wallops under all defined conditions However, EIRP needed to operate to DRGS with GOES 11 or 12 depends on actual loading

10. 10 GOES 11 and 12 Loading August 2006 measurements show: –Average is 25 to 30 channels at 45 dBmi –Worst case is 61 channels (2 x 1 second per day) March 2007 transponder AGC confirms –Average RF equal to 30 channels at 45 dBmi –Peaks at 55 channels at 45 dBmi (for 4 sec max) April 2007 data give same 45 dBmi average –Also show usage of 3.3% to 37% of capacity in the twelve channels common to both DRGS

11. 11 Possible EIRP Options Create a program to reduce high EIRPs and the peak number of simultaneous TXs –Set the v.2.0 EIRPs to be compatible Allow v.2.0 to set high EIRP ranges for operation with GOES 11 and 12 then require they be lowered for GOES N/P –Remote control of EIRP would be helpful Set v.2.0 EIRPs high enough for all satellites and accept higher power requirements Require v.2.0 DCPs not be placed in service until after GOES 13 becomes operational

12. 12 Possible EIRP Ranges v Loading Required EIRP ranges for CS v.2.0 (dBmi) Maximum loading on GOES 11/12 for DRGS 37 to 41 Mid = 39 30 channels at 44.5 dBmi avg 80 channels at 40.3 dBmi avg 39 to 43 Mid = 41 60 channels at 44.5 dBmi avg 80 channels at 43.2 dBmi avg 41 to 45 Mid = 43 105 channels at 44.5 dBmi avg 80 channels at 45.7 dBmi avg Calculation made for the mid-point of each range 1 dB margin is included

13. 13 Summary Proposed EIRPs work into Wallops at all transition stages at estimated w/c loading Proposed EIRPs work into 15 dB/K G/T on GOES-13 at estimated w/c loading Operation of proposed EIRPs to DRGS on GOES-11/12 depends on number of simultaneous TXs and average level –Difficult to predict conditions to be used for DRGS reception conditions –Different ranges could be set for each generation of satellites

14. 14 Recommendations Recommend 37-41 dBmi for 300 bps and 43-47 dBmi for 1200 bps be accepted for GOES N/P Recommend additional, higher EIRP levels be permitted for use with GOES 11 and 12 Propose insert an additional clause in CS v.2.0 subsection 4.1.1 –Operation with EIRP up to 47 dBmi for 300 bps links and 50 dBmi for 1200 bps links is permitted only when transmitting to the GOES 11 or GOES 12 satellites Remote control of the EIRP need not be required, but it would make it easer and quicker for users to make adjustments at the transition

15. 15 AverageMinimumMaximumTotal E on E44.627.953.1160665 W on E34.826.451.298492 W on W45.729.255.5161186 E on W35.526.954.790931 All channel EIRP in dBmi measured relative to Pilot Backup: EIRP Summary Aug 06

16. 16 Backup: EIRP on April 8, 2007 Data from both Signal Engineering and Microcom DRGS reception showed: –Average EIRP on GOES East = 44.7 dBmi –Maximum EIRP on GOES East = 54 dBmi –Only for a subset of GOES East channels but does tend to indicate stability

17. 17 Example: Channel 163 It seems to be almost fully allocated with 10 second time slots 342 allocations with 1 hour repeat intervals Leaves only 18 slots un-allocated 342/360 = 95% However, on April 8, 2007 the actual transmit time was probably only 32,000 seconds –This is only 37.0% of capacity

18. 18 Backup: Channel Usage April 8, 2007 Channel Number Time Used (%) Channel Number Time Used (%) 710.95515.2 1714.26710.8 3127.78923.3 3515.31293.3 4113.916337.0 4919.217713.7

19. 19 Backup: Simultaneous TXs Aug ‘06 Average Number of ST Maximum Number of ST East channels on GOES East 18.742 All channels on GOES East 27.958 West channels on GOES West 15.039 All channels on GOES West 26.161