Holux GPSlim 236 Locking

jason.drew · 10-11-06, 07:44 AM

Hi

I was just wondering if anyone has had problems with their GPSlim 236
acquiring the signal. I know I turn it on in a built up area (Budapest) but it
sometimes takes 5-10 mins to get a lock. Once it is locked it seems to
keep the lock, even in the places it couldn't get the lock in the first place.

Is my unit ok? Is this just GPS?

Jason

JakeRich · 10-11-06, 08:50 AM

In urban canyons, it can take a while to get the first fix. That delay can be extended if you move around while it is trying to get that first fix. It can also be delayed if the signal strength is marginal, as it would be if you are trying for the first fix indoors, inside a vehicle like a bus, or under leafy trees. That's just the way GPS works.

jason.drew · 10-11-06, 09:20 AM

Originally Posted by JakeRich

In urban canyons, it can take a while to get the first fix. That delay can be extended if you move around while it is trying to get that first fix. It can also be delayed if the signal strength is marginal, as it would be if you are trying for the first fix indoors, inside a vehicle like a bus, or under leafy trees. That's just the way GPS works.

Thanks for that.

To be fair I am moving around, in a car which is passing
by leafy trees in an urban canyon.

I guess everything is working well then. :)

Thanks again

Jason

myrcgarage · 10-11-06, 01:24 PM

Jason, I timed mine. It takes about the same amount of time to get a lock if I am driving around. If I am standing still outside, it takes about 40 secs to get a lock. If I am inside my house on the 2nd floor(top floor), it takes less than 1 min.

jason.drew · 10-12-06, 02:55 AM

Originally Posted by myrcgarage

Jason, I timed mine. It takes about the same amount of time to get a lock if I am driving around. If I am standing still outside, it takes about 40 secs to get a lock. If I am inside my house on the 2nd floor(top floor), it takes less than 1 min.

Hi

Do you mean it takes 5-10mins when your driving around and less than 1 minute
standing still or less than 1 minute regardless of what you're doing.

Thanks

Jason

myrcgarage · 10-12-06, 09:58 AM

Originally Posted by jason.drew

Hi

Do you mean it takes 5-10mins when your driving around and less than 1 minute
standing still or less than 1 minute regardless of what you're doing.

Thanks

Jason

Less than 1 min if I stand still(not moving)

Starboss · 10-14-06, 09:01 PM

I've never had it take longer than a minute unless I'm in the downtown (Toronto) area and severly blocked by buildings.

Doug

jason.drew · 10-17-06, 07:51 AM

I think I will have to take it back.

The other day it took about 30 minutes to lock and there was plenty of
times when I was still for about a minute (at traffic lights) and there
was a good view of plenty of sky. It was as good as useless and very
frustrating!

Can anyone recommend a better unit, I would think twice about another
Holux

Thanks

Jason

jason.drew · 10-17-06, 08:41 AM

Originally Posted by jason.drew

I think I will have to take it back.

The other day it took about 30 minutes to lock and there was plenty of
times when I was still for about a minute (at traffic lights) and there
was a good view of plenty of sky. It was as good as useless and very
frustrating!

Can anyone recommend a better unit, I would think twice about another
Holux

Thanks

Jason

Just to give people more details, I am looking at the unit now, it can see 3-4 satellites,
each with about 30% signal strength (not sure what that is in real money) and
still I don't have a lock. I am not moving. Is it the software, is it the bluetooth
(I am connected to the unit so I doubt it).

Why is it so rubbish?

Jason

ChillyCat · 10-17-06, 10:42 AM

As with any mass produced product , there's the inherent possibility of recieving a "lemon".

I'd assume [by the troubles you're having] you've been *cough* blessed with one of the yellow ones :(

I have absolutly NO preference for any particular manufacturer of GPS recievers, but found my 236 for $60ish via Ebay. The thing operates flawlessly and TTF typically is under 20 secs. I've had a couple of orange led locks, but a battery removal solved that issue. Its only happened a couple of times and the company that sold it to me offered to replace it....should I wish to do that.

Are you able to return your unit for warranty exchange ?

jason.drew · 10-17-06, 11:14 AM

Originally Posted by ChillyCat

As with any mass produced product , there's the inherent possibility of recieving a "lemon".

I'd assume [by the troubles you're having] you've been *cough* blessed with one of the yellow ones :(

I have absolutly NO preference for any particular manufacturer of GPS recievers, but found my 236 for $60ish via Ebay. The thing operates flawlessly and TTF typically is under 20 secs. I've had a couple of orange led locks, but a battery removal solved that issue. Its only happened a couple of times and the company that sold it to me offered to replace it....should I wish to do that.

Are you able to return your unit for warranty exchange ?

Yes I can take the unit back. I've been searching the web and it does seem
that some users have an acute problem of getting a lock when moving,
particularly at high speed

http://www.gpspassion.com/forumsen/t...1&whichpage=21

http://www.gpspassion.com/forumsen/t...09&whichpage=2

I don't know if the unit is defective or as one person suggests:

"Seems after a certain time without lock the unit discards all cached position data and starts scanning from the very beginning"

Could the firmware be upgraded. How can I check my version? There seems to be
some truth in this as I can now get a lock in less than 1 minute as I write this mail
(unit turned on and off) whereas for the first time it took around 15 minutes
in the same position. Maybe the position cache is valid now.

Have you tried any experiments?

Jason

JakeRich · 10-17-06, 04:20 PM

Quote:

"Seems after a certain time without lock the unit discards all cached position data and starts scanning from the very beginning"

That is how GPS is designed to work. Moving during the first fix can make that happen over and over. It's not so critical with multi-channel receivers, but it still happens. Read question 6 here.

jason.drew · 10-18-06, 03:13 AM

Originally Posted by JakeRich

That is how GPS is designed to work. Moving during the first fix can make that happen over and over. It's not so critical with multi-channel receivers, but it still happens. Read question 6 here.

Thanks for that, a really interesting summary of cold, warm and hot fixes.

I guess that I should be warm fixing most of the time (is it really 200 miles
movement with it switched off to trigger a cold fix?) but it seems as if the unit is
cold fixing on power up (particulary after a longer period of power off time).
Does this mean the following:

1 The almanac data is being lost via battery failure (a faulty unit but my
battery seems fine)?
2. Tha almanac data is being wiped for some other reason (bad firmware)?
3. The almanac data is being lost as any internal non-volatile memory is failing?
4. ????

All in all, it doesn't seem that it should be cold fixing, yet it is.

Anyone else experience this?

Jason

JakeRich · 10-18-06, 08:48 AM

Cold fixing every time is not normal if you use it the unit every day. The Almanac and Ephemeris data is usually good for 3-4 days. After that, it's aged out so that you have to receive it again. Basically, in my normal use to/from work I can get a warm fix on Monday from my Friday commute, but if I wait until Wed or so, then I end up with a cold fix.

So, if it's cold fixing every day, something is wrong and you should ask for a replacement.