Garmin GPS - Strange "weak signal" problem with 60CSx

Author

Strange "weak signal" problem with 60CSx

eeBCLee@gmail.com

2006-02-16, 2:48 am

I've had a 60CSx since Sunday, today it did a weird thing, just
wondering if anyone has seen or can explain this:

I drive through a tunnel on the way home where it always loses the
satellite signal, beeps and pops up the message, and I hit enter. As
soon as I'm out it gets the signal again, at least the previous two
days. My 76S would do the same thing.

Today I was distracted and didn't hit enter when the message popped up.
Just at the end of the tunnel it beeped a second time, I didn't look
closely at the screen but I assumed it was the same message. Maybe
half a mile to a mile out of the tunnel I noticed the message was still
there so I hit enter. Then it had the flashing question mark at the
position of the entrance to the tunnel, and no lock. I drove on, and
after a bit realized it still wasn't getting a lock, it was still
showing the flashing question mark at the entrance of the tunnel, and I
had now been out in the open for at least 3 miles. So I switched to
the satellite screen, and it showed all the satellites as having no
signal and said "weak signal" at the top. It seemed to have just given
up. I let it go for a while longer, but still it got nothing. The
satellite page looked like I was still in the tunnel.

Finally I hit menu, selected "use with GPS off" then went back in and
chose "use with GPS on" -- 8-10 satellites immediately showed full
filled bars and it had a position. Hmmm.

When I got home I decided to try and reproduce this by driving into our
parking garage (half underground, with 4 floors of apartments on top of
it) to lose the signal and then drive out to see if it just gave up or
what. But I was mostly thwarted -- the 60CSx never lost its lock in
the parking garage. I eventually pulled out a aluminum clip board and
held that over the unit, and got it to say it lost the signal, but I
never got it to beep a second time, and as soon as I left the garage it
had a position right away again. So I'm not sure I really reproduced
the same conditions.

I guess on my way home tomorrow I'll try to reproduce this in the
tunnel. But I'm just wondering if anyone has any information I might
be missing -- for instance, in the garage it was probably still getting
a weak signal, was the second message in the tunnel some special thing
that comes up if it has zero signal for too long? Is this a feature or
a bug?

Other than that I've been amazingly happy with this GPS, it's just a
great unit.

-- Brian

eeBCLee@gmail.com

2006-02-21, 5:49 pm

I got email that others have seen this, and I emailed Garmin. The
folks at Garmin say:

"This is caused by the new Sirf receiver. It wants to have a better
lock then the 12 parallel channel receiver so it is more sensitive
after loosing reception. They are working on updates to possibly
improve this in your unit. In most cases the unit will relock when you
stop but you may have to cycle the power to relock. Keep an eye out on
our web site for future updates."

Phil Wheeler

2006-02-21, 5:49 pm

eeBCLee@gmail.com wrote:
> I got email that others have seen this, and I emailed Garmin. The
> folks at Garmin say:
>
> "This is caused by the new Sirf receiver. It wants to have a better
> lock then the 12 parallel channel receiver so it is more sensitive
> after loosing reception. They are working on updates to possibly
> improve this in your unit. In most cases the unit will relock when you
> stop but you may have to cycle the power to relock. Keep an eye out on
> our web site for future updates."
>

Ah .. the "tunnel problem". Thanks for the info. It will be
interesting to see if a firmware fix is possible, given that SiRF
appears to have lots of processing internal to it .. vs. in firmware.

My 60Cx is arriving today. Having a GPSR in my car, I will seldom use
it while driving .. and there are no long tunnels in this area :)

May run into the issue when traveling with a rental car, but that is seldom.

However, it seems that the problem above could occur while hiking,
assuming the GPSR is left on in deep canyons and such. I do hope they
get a resolution. Until then, worst case is that you have to cycle
power, I guess.

Phil

LinkBot