Re: Legend C and Vista C sensitivity

From: Simon Long (simon_at_longnews.freeserve.co.uk)
Date: 08/10/04 

Date: 10 Aug 2004 02:37:25 -0700

"David Lee" <davidlee_malvern@dont.use.this.bit.hotmail.com> wrote in message news:<cf86fd$r01$1@hamble.qinetiq.com>...
> I have had a basic yellow etrex for the last two years and have been happy
> with it. However I have carried it around a local nature reserve several
> times and have measured very erratic tracks, with frequent loss of signal,
> even when I carried the unit in my hand, patch antenna looking up. The
> reserve is fairly wooded - densely in places - so I assumed that this was
> the reason for the poor quality of the track. A couple of months ago I
> bought a Vista (mistakenly thinking that it would be an upgrade!). The
> tracks recorded by the Vista under the same conditions (sometimes carrying
> both units one in each hand) were even poorer.

My first GPSr was an eTrex Summit, bought in 2000, on which reception
was pretty good. I never really tried using it under canopy, but it
very seldom lost lock when in the car, and would quite happily acquire
satellites sitting on my bed under the window, or on my desk at work
(again, near a window).

I too then "upgraded" to a Vista in 2002 - and the reception on that
was markedly poorer than on the Summit. It quite simply couldn't get a
lock inside a building, no matter how close you were to a window. It
wasn't too bad once you were outside, but it had a tendency to lose
lock altogether occasionally while driving across flat, open country
with a clear skyview in all directions.

I was most unimpressed after the Summit. As most of us do, I patched
the firmware every time an upgrade came out, and after one such
upgrade, the sensitivity got a *lot* better. Not quite as good as the
Summit, but I could now usually get a lock indoors by a window. So
it's not just the hardware that affects sensitivity - and yes, Garmin
do play about with stuff after release.

I've now got a 60CS, which can get a lock in my (windowless) top-floor
bathroom through the ceiling and the roof - it's in a different league
from the Vista and the Summit.

For work, I once had to evaluate a receiver using the SiRF chipset,
and to anyone used to a Garmin receiver, this thing was a revelation.
Genuine warmstart times under 15 seconds, and the thing would maintain
lock no matter what you did to it, within reason. It needed a more
beefy power supply than 2 1.5V AAs though, which probably had a lot to
do with it.

Simon

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