[time-nuts] Question on LH
chris at chriscaudle.org
Wed Dec 7 14:54:25 EST 2016
On Wed, December 7, 2016 12:51 pm, David C. Partridge wrote:
> But in any case at the end of the LH 48 hr survey, the survey location
> will be stored into the currently connected TB. If both TBs are connected
> to the same antenna, I think you'll need manually to set the location of
> the second one (lat./long./altitude) based on the survey results stored in
> the other one.
Mark has explained previously on the list, but it is actually kind of
convoluted. The command to set the position does not accept enough
numeric precision to accurately set the position which was determined from
long term averaging, so LH causes the Thunderbolt to run short self
surveys (which report the position to more numeric digits than the set
command will allow you to set), and compares the reported position to the
position derived from the long term average. When one of the self survey
results just happens to be within some small error of the determined
position, then that self survey result is saved.
So if you manually set the position on a second Thunderbolt, the software
will chop off the lower order digits of the number you give, and the two
thunderbolts could have very slightly different performance, even running
from the same antenna.
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