1 CS v.2.0 Outstanding Items DCS Manufacturers Meeting June 13, 2007 Peter Woolner Noblis

2 Antenna Info on Nameplate The change to section 1.3 d) discussed at Asheville has been accepted The revised text is: Approved antenna gain, polarization, and type for use with this DCPRS (e.g. 11 dBi RHCP Yagi)

3 Carrier Turn-on Time Details Average -1 dB +1 dB t=0t=5 Time to 250 or 500 mS Positive overshoot is not relevant to turn-on time Undershoot must be less than 1 dB Rise time must be 5.0 mS maximum to -1 dB from average Output Power

4 Encoder Flush and Carrier Turn-Off The revised wording is: At the end of the message after the EOT, an additional 32 zero (0) data bits shall be input to the encoder to flush the encoder and decoder. This shall result in 16 symbol periods in which zero phase is transmitted, after which the carrier power shall be turned off. The turn-off transition shall not start until the end of the 16th symbol period and shall be a maximum of 15 milliseconds in duration, in which time the power shall be reduced by at least 50 dB.

5 Short Term Frequency Stability The previous text reflected the limitations of old generation frequency counters. The revised text is intended to ensure the 1 Hz/sec is understood as a rate limitation, not an average over 10 seconds (or any other time period). The turn-on time is specifically included in the measurement process.

6 Phase Noise Measurement The proposed new text is: The phase noise of the unmodulated carrier shall be equal to, or less than 2.0 degrees RMS, when integrated over the range 2 Hz to 150 Hz for 300 bps, and 6 Hz to 600 Hz for 1200 bps. Certification testing may use any frequency range that includes either or both of these ranges, e.g. a measurement for 2 Hz to 1000 Hz could show compliance for both data rates. The 2.0 degree limit shall be met under any combination of operational conditions. Also at the start of Appendix A, it is noted that COTS may be used, or the NOAA test set, and that “other items of test equipment are not prohibited” but must be proved.

7 DCPRS Transmit Spectrum Instructions on making this measurement were moved to Appendix A and enlarged. A range of Spectrum Analyzer settings is presented with some basic restrictions and a list of what these measurements are required to show. The following diagram is included.

8 Transmit Spectrum Measurement This is a noise-like signal Use enough averaging to locate the peak of the theoretical curve Each out-of-band emission limit shall be measured from the peak of the theoretical curve to the highest peak in the out-of-band frequency range The modulation sidelobes may be noise-like or may also contain a CW component Reference level is peak of theoretical curve shape

9 Spectrum Measurement Notes Averaging will reduce the noise-like variances of digital power spectral density Averaging that will combine sequential sweep traces and/or FFT bins may be used Averaging MUST NOT combine responses at different frequencies –VBW must be at least 3 times RBW –The spectrum measurement must be able to show that any CW-like emissions as well as the noise-like emissions are below the required levels