How long did you get your self survey time to?If you have the time, use the 171000 minutes which is just under 48 hours and that should be much more accurate. The other possibility is that you have your mask angle too low for timing all you need is a mask angle of 15 degrees or greater to prevent multipath and other items like that.Michael  Sent from my Verizon, Samsung Galaxy smartphone -------- Original message --------From: Mark Barettella via time-nuts <time-nuts@febo.com> Date: 6/26/16 6:02 AM (GMT-07:00) To: time-nuts@febo.com Subject: [time-nuts] Impact of GPS antenna height measurments Using auto survey mode my gps antenna height is significantly off.  I estimate my antenna’s actual height at about +5 m high and the gps indicates -17 m. My question is will this adversely influence the accuracy of the gpsdo output?  Would there be any benefit to adjust this manually via the scpi commands? Thanks, Mark Windows 7 Pro SP1  64 bit GPScon-JLT v 2.007 Fury firmware rev. 1.22 w/ M12M upgrade PCTEL 8171D-HR-DH-W antenna _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.