At 03:42 PM 10/6/2023 +0000, Zach Metzinger wrote:

Hello all,

While listening to this morning's AO-91 pass, I noticed CW-modulated noise in the background. So did one or more operators on AO-91, who thought that the station was trying to send CW through AO-91.

Switching over to CW mode, I copied: "manfred es christ fuchs 73 de ii3mv max valier sat manfred es christa fuchs 73 de ii3mv max"

This turns out to be the Max Valier satellite, launched in 2017, which (unfortunately) uses Amateur Radio spectrum for a scientific downlink and does not provide any communication resources in return.

AO-91's downlink is close enough to Max Valier's that, with Doppler correction, may make it into your receiver's FM discriminator and show up as CW-modulated noise when AO-91's signal fades.

Hopefully, this note will inform other stations that one should not assume intentional or unintentional interference without verifying the origin of the signal received.

73,

--- Zach

This happens more than you think. One neat feature of InstantTrack you can see what satellites are co-visible to each other. It was always fun do try and make cross satellite contacts. Easiest to do on linear satellites where the downlink of one is in the uplink of another.

KB7ADL