Just a quick update and summary of my experiences: APRS on 2m does not make a lot of sense for the majority of SOTA summits in the Stubai/Sellrain region near Innsbruck. On 4 - 5 trips to summits in that region, I carried my VX-8 with 5 W and used with a Diamond SRH-771 SMA better-than-factory antenna with me, attached to the upper part of my backpack and sending out beacons frequently (1 … 5 minute intervals).
Only on two summits by signals were heard at all by at least one I-Gate and made it into aprs.fi, but only when I was already on the very summit (plus/ minus a few minutes). The part of my trip that was observable via aprs.fi was only a few minutes of 4 - 8 hour hikes.
I think the main problem is
- A lack of I-Gates and digipeaters in the region and
- The topology with steep valleys and remote summits (also cell-phone coverage is often very bad).
On one occasion, I was able to listen to a CQ call on 145.500 but could not answer because I was busy with my group.
The bottom line for me is that it does not make sense to carry my handheld FM rig for similar trips, because the gain for chasers is very limited.
73 de Martin
PS: You can analyze the few raw packets on aprs.fi if you want - the SSID was DK3IT-7.