Does Battery-Saver Mode Impair Acquisition?

I noticed something odd yesterday. It had been awhile since I powered up my
eTrex Legend Cx. I had since done a firmware update (v3.40) and not used it
since about 250 miles away. While experimenting with new maps and settings
I also chose the "new location" a few times from the menus without ever
having used it to update the data direct from the satellites. I suspect it
was essentially "location blind" by this time.

When I turned it on it seemed to be taking an inexorably long time to
acquire the usual satellite locks. Which normally would happen in under a
minute. It never did lock onto any satellites when placed on the sill of a
large picture window (where it normally had no problems doing so). So I
stood out at the end of my long driveway where there are no trees, thinking
that would help. Granted it was a heavy freezing rain at the time, so that
might have had something to do with it. But still no lock, for what seemed
to be upwards of 10 minutes or more.

I then realized ... after the new firmware install, I had put it to
"Battery-Saver" mode, after reading up what that undocumented setting does.
It supposedly only polls the satellites once a minute or something instead
of continuously.

I took it off of "Battery-Saver" mode and now within 1 minute it was
locking onto and downloading the needed data.

Does "Battery-Saver" mode impair satellite-lock during power-up in all
units? Or was this just a spurious example that had nothing to do with that
setting? Was it the weather, the new firmware update, or my having not
logged into the satellites in about a month?

Considering how fast it locked onto the satellites after I took it off of
"Battery Saver" mode, I strongly suspect that was the reason. But perhaps I
just had not waited long enough and it would have done it anyway with that
setting engaged if I had waited just one more minute before disabling that
feature.

On 1/26/10, Charles G posted:






Yes, the power of coincidence, as well as trying to discern what is
cause vs. what is effect.

If I were programming a "Battery Saver" mode, I would arrange to
override it during satellite acquisition. What the Garmin programmers
did is known only to them, I guess :-)

In your shoes, I might consider running a series of tests, a day or two
apart, starting alternately in and out of BS mode.

So I am sympathetic, but otherwise of no real help, sorry...

--
Gene Bloch 650.366.4267 lettersatblochg.com

On Tue, 26 Jan 2010 16:26:08 -0800, Gene E. Bloch


Yes. And so far we all know how much the programmers for Garmin actually
USE the GPS devices and support programs in real-world situations before
they release their work. It wouldn't surprise me one bit if they forgot to
override this "Battery-Saver" feature during acquisition. It would surprise
me more if they had remembered to consider this, considering they don't
even tell you exactly what it does in their own manual. :-) This is why I
have to ask those who have more real-world experience than they.

I'm not going to do any extensive testing of my own. I'll just find out as
the year goes on I guess, unless others report similar occurrences. Should
I notice a pattern with "Battery-Saver" engaged, I'll remember to turn it
off whenever I have to start up in a new location or it seems to be taking
far too long to do a satellite lock. If nothing else, it's one little
data-point to consider for anyone else having start-up acquisition delays
that seem far too long.

From this scant anecdotal and unresearched experience, I'll now presume
that 'Battery-Saver' mode should only be engaged after the unit is up and
running well. And, according to other's reports, that it should only be
used when traveling slowly. Not in a car, not on a plane, not in a train,
not on a boat, not with a goat. Sam I am. (Okay, well, maybe when on a
goat.)

This will be one of those posts, that when you are 250 miles from nowhere
and think to yourself, "Hmm... I recall reading something on the internet
about this. They turned off 'Battery-Saver' mode and it finally locked onto
satellites. I wonder if that'll help ..." Then when they are safely back in
civilization again they'll have forgotten all about telling others what
little button-sequence finally saved their life. :-)

Everyone, at your own discretion, please update your extensive and
comprehensive Garmin owners' manuals accordingly. :-)

On 1/26/10, Charles G posted:



Who ever heard of using the programs or devices you design? Too
radical. It seems to be not limited to Garmin, truth be told...


OK. I was hoping you were more obsessive-compulsive than that :-)


I laughed about the goat. For one thing, I'm partial to goats (no, not
that way!), since I do eastern-European folk-dancing; their bagpipes
are typically made from goatskins.

The word for bagpipe in a few languages there is gajda (pronounced
guyda) and in Spanish it's gaita, both claimed to be from a Gothic word
for goat (as is the word "goat").


Are you a playwright? You seem to have the touch...


--
Gene Bloch 650.366.4267 lettersatblochg.com

Gene E. Bloch wrote:

I think that if I were a goat I would prefer impartiality!

Mike.
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