WRC-23 Day-6: 50MHz and 23cm

Week-2 of WRC-23 started with a 9am meeting of the AI-9.1b, 23cm topic, followed by 40-50MHz radar sounders.

The latest 23cm meeting considered a draft CEPT Resolution to incorporate/mandate the levels in new ITU Recommendation M.2164 to protect radio-navigation satellites (RNSS) in 1240-1300MHz. This predictably ran into some concerns from other regions. Alternatives on the draft resolution text, or potentially a regulatory footnote continued to be considered, but the Chair recognised things were going in circles. The lack of progress resulted in a frank report to the higher level working group later in the day. One more meeting is scheduled for Tuesday morning. The item is also resulting in fairly high attendances for an amateur radio topic.

Following this came another key topic of interest. AI-1.12 on 40-50 MHz radar sounders did see some progress. After merging various proposals, multiple satellite-borne radars (with ~10dB gain yagi antennas) would be free to transmit over polar regions (now at any time day, not just at ~3am), with restricted operation outside the defined areas, unless agreed to by the countries concerned.

IARU is particularly concerned that these have wideband transmissions and will cause an issue in the adjacent 50MHz weak signal DX segment. For technical reasons the radars don’t fully turn off, so there is a complex set of power flux density limits in/outside polar regions and in the adjacent 50-54MHz band that are yet to be decided.

Both topics will continue

The RSGB’s social media and special focus page at rsgb.org/wrc-23 will feature regular postings whilst the conference is underway.

Category: Front Page News, WRC-23