Hi Mike,
why I'm no longer able to digi via the ISS ...
There are a few issues with the amateur radio equipment aboard the ISS. The only working ham rig at the moment is the 5 watt Ericsson HT. So the downlink is weaker than what we historically recall. The FM deviation seems a bit more narrow as well.
This report from the ARISS International meeting may offer additional insights:
http://www.arrl.org/news/ariss-international-partners-regroup-at-first -in-person-meeting-since-2011
I hope the mailing list doesn't mangle the long URL. Anyway, when you get halfway through this article there is a link called 'presentation' which gets you the PowerPoint slides from the meeting. The ARISS radio gear is discussed in the slides.
I've also found that orientation of the ISS with respect to my QTH affects how well I am heard on the uplink and how well I hear the downlink. Perhaps that is another reason the APRS gates aren't copying.
When you see my greetings on 145.825 I am always at the keyboard ... no beacons here. We can try for a packet QSO.
-- 73 de JoAnne K9JKM k9jkm@amsat.org Editor, AMSAT Journal