[time-nuts] Tuning a Trimble Thunderbolt

Bruce Griffiths bruce.griffiths at xtra.co.nz
Wed Apr 22 06:56:58 EDT 2015

A week is somewhat optimistic since the thunderbolt consumes around 1.68 kilowatt hours of energy. With a 12V battery a capacity of around  84 ampere hours (for an efficiency of 100%) which is somewhat larger than that provided for most UPS particularly those sold for use with personal computers. .Whilst the UPS may use a higher battery voltage the energy requirements are similar as will be the physical size and weight of the battery/battteries.

     On Wednesday, 22 April 2015 6:33 PM, Chris Albertson <albertson.chris at gmail.com> wrote:

 On Tue, Apr 21, 2015 at 1:30 AM, Pete Stephenson <pete at heypete.com> wrote:
> On Tue, Apr 21, 2015 at 4:25 AM, Charles Steinmetz
> Indeed. I'm running a 48-hour survey with Lady Heather now to see if
> that can improve things a bit more.

You can let the GPS receiver do a self-survey but you can also enter
the location that you determined by other means.  I've not done this
on a Thunderbolt but have for my Motorola receivers.    Just by chance
I needed to get my property surveyed and had a crew out and they
marked the property with brass markers positioned to a fraction of an
inch. (I hope)  From this I can figure out the antenna location to
likely about one foot or maybe better if I am really carful.

One thing to watch out for is that there are different "systems" of
measuring latitude and longitude these make different assumptions
about the shape of the Earth and where its center is located and so
on.  You need to be sure everyone is using WGS84.  If not it is easy
to be "off" by a couple hundred meters

You can use Google Earth if you don't have a survey but check it for
accuracy.  Have Google check the location of a government benchmark
that is nearest your house and see if Google gives you the recorded

It's good to find the antenna location using other means so you can
verify the self-survey..  I did this and found it is all OK within
some margin of error.  But then I have a very good antenna location.
I think with a poor antenna location you'd want to verify the


Chris Albertson
Redondo Beach, California
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