Here is a screen shot of my RX waterfall showing the pattern of CAS-6's downlink... it's a challenge to say the least, but at least if you know the pattern it's possible to TX at just the right time.
https://twitter.com/scott23192/status/1274537862843826176
... I have to confess that if this pattern of extremely brief operational windows continues, I'm going to be awfully tempted to see if anyone would like to try some satellite MSK144. But I know it's early and hopefully the situation will improve for voice comms.
-Scott, K4KDR
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On Sun, Jun 21, 2020 at 5:12 PM Lapo Pieri via AMSAT-BB amsat-bb@amsat.org wrote:
Hi, during last pass over Europe of CAS-6 (2020-06-21 ~20:30Z) I've experienced the problem already reported here few days ago: even with 10-15W EIRP after a couple of seconds in TX trasponder cut off my signal. I'm quite sure to be not over beacon level. The beacon appares unmodulated. Heard few station calling but get only part of callsign for the same problem.
73, Lapo IK5NAX