Had alot of fun with these APT satellites over the years. I still remember setting my AOR-3000A scanner on vox recording to my pc back in 98 before leaving for school trying to catch NOAA-15. No tracking and no doppler correction. The results were not great to say the least but that did not matter.
I never got around to S-band HRPT because of strict houserules against dishes… Something i still at the age of 46 have to contend with
I guess these satellites have done their job and are now redundant. But we still have the russian LRPT/HRPT satellites and as far as i know they are planning MET M2-5/2-6 as well.
Initially, it was thought that this meant that transmissions would cease. However, Carl Reinmann has now clarified with NOAA that transmissions of the APT and HRPT signals will continue as usual. Importantly, NOAA urges that these transmissions will only be “data of opportunity” and should no longer be used for operational purposes (not for anything safety-critical, for example). The transmissions will be fine for everyday hobbyist use.
On May 31, 2025 at 1605 UTC, the NOAA-18 S-band Transmitter 4 (STX4) experienced a power drop from 7W to 0.8W. STX4 is the only remaining transmitter used for up-link (commanding) and downlink (telemetry & global science data from the recorder). Full recovery of the S-Band transmitter and its functionality is not possible, and therefore jeopardizes the ability to ensure safe operation of the spacecraft. Based on NOAA’s requirement to responsibly manage on-orbit assets, NOAA will decommission NOAA-18 on June 6, 2025 between 1733 and 1749 UTC.
Last NOAA-18 transmission over my QTH, I think it’s last orbit before turned off. Quite sad as it’s the first satellite that I manage to capture with RTL SDR. Ironically that very same SDR is now used on my station to capture its last signal .
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