First, the bigger the antenna the greater the reliability.
If you are using QRP, then try during off-hours, Local time M-F 9am – 3pm, 11 PM – 5 AM, Weekends 11 PM – 5 AM. All other times can be considered peak hours, when it will be harder (not impossible) for a QRP station to access the BBS or Unrproto on ISS.
http://www.marexmg.org/fileshtml/howtouseiss.html
--- On Sun, 11/2/08, Allen Vinegar tokens@myranch.com wrote:
From: Allen Vinegar tokens@myranch.com Subject: [amsat-bb] Starting out on packet mode. To: amsat-bb@amsat.org Date: Sunday, November 2, 2008, 4:25 PM How can I start out on packet mode with the ISS using a TH-D7AG in a handheld operation with an Arrow antenna? _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb