Now that I have a precise spot (+/- 4cm) known on my front deck I set up a tripod and did numerous 1400 point self-surveys with a Thunderbolt. This spot is surrounded by very tall trees and multipath from the trees, steel gates and stucco walls, a house, an iron fence, etc. I used four different antennas:
1) A Sokkia geodetic grade L1/L2 antenna 2) A Aero survey grade L1 only antenna 3) A Datum timing antenna 4) A cheap patch antenna I could not find any repeatable differences in the performance of any of the antennas. The $3000+ geodetic grade antenna performed no better than the cheap $5 dollar patch antenna. Composite performance over 22 runs was: Avg lat error: 1.4 feet, std dev 4.48 feet Avg lon error: 2.24 feet, std dev 2.87 feet Avg alt error: 6.00 feet, std dev 15 feet Although I did not do any extended timing tests between the antennas, the numbers that I did see make me suspect that timing performance among the antennas would be similar. A couple of 24 hour runs between the cheap patch and the geodetic antenna were the same. A cheapskate could probably get excellent results by mounting a cheap patch antenna in the middle of a large pizza pan ground plane. _________________________________________________________________ Windows Live™: Keep your life in sync. http://windowslive.com/explore?ocid=TXT_TAGLM_WL_BR_life_in_synch_062009 _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
