HI-303MMF very long TTFF

andrems · Posted: Sat Jan 01, 2005 4:05 pm Post subject: HI-303MMF very long TTFF

Hi,

I have a HI-303MMF, which I normally use as a CF GPS inserted in my ipaq hx4700. Usually I have to wait 1 - 2 mins for TTFF. But recently happened to me two times that when I turn the PDA on and run TOM TOM GPS, it doesn't find any satellite for almost 10 minutes or more. After finding the satellites it takes 1-2 mins for fixing. Both times this happened, I was walking under a clear sky.

What could be causing this extreme delay to find any satellite? Question

Could the GPS be deffective? I don't think it's the internal battery because the PDA is almost all the time in the charger with the GPS inserted in the CF slot.

Thanks for your time, Smile

Andre.

DavidW · Posted: Sat Jan 01, 2005 8:44 pm Post subject:

It could be that the internal supercap in the HI-303MMF is going flat when it's not being used, leading either to the clock running slow, or the memorised last position being corrupted. Just keeping the hardware in the cradle, switched off, won't keep the GPS hardware powered up. I find the supercap in my HI-303MMF lasts about three days.

If you downloaded Winfast (Leadtek) Navigator and had a look at the time and date being returned, you'd be able to see if this was your issue. If it is, the quickest way out is to issue a cold start command, which will tell the GPS to discard the faulty time and/or last position and start to fix from scratch, which typically takes no more than 2 minutes.

It's best if you're not moving when you're trying to get a first fix.

David

andrems · Posted: Sun Jan 02, 2005 12:10 pm Post subject:

Thanks for your answer David.

You might be right since I noticed one of the times that the GPS clock showed by TOMTOM GPS was completely different from the actual time.
Now I have 2 questions.
1- Is there a way to prevent the supercap from discharging completely without having to put it on the PDA whilst is on?
2- How can I issue a cold start command? What software do you recommend?

Andre

andrems · Posted: Sun Jan 02, 2005 12:26 pm Post subject:

Ok, I read the other topic here about a problem similar to mine posted an year ago.

I just wanted to say that one of the times this problem happened I used TOMTOM "Reset GPS for this location", pointing to the location on map near I was, and nothing happened. Still not a single satellite for 10+ mins.

DavidW · Posted: Mon Jan 03, 2005 5:43 pm Post subject:

One way to prevent the supercap discharging would be to get hold of a cable that you can apply power to, and use that. There may well have been a PS/2 and DB9 serial cable in your HI-303MMF's box - if there was, just connect that to a spare PS/2 port on your PC, if you have one, and connect the GPS to the cable, which will keep the GPS powered up.

If you plug in a cable, you must remove the GPS from its CompactFlash slot.

"Reset GPS for this location" should help - but it will only work if you've got the correct setting in TomTom GPS. Try "Haicom GPS" or "TomTom Navigator GPS" - both are correct for a SiRF based GPS in NMEA mode at 4800bps.

For issuing a cold start command, try Leadtek (Winfast) Navigator.

David

andrems · Posted: Mon Jan 03, 2005 10:14 pm Post subject:

Your cable idea made another question on my mind. I have the BT slipper. Can I connect the AC power adaptor directly to the 303MMF since the conector is equal?

Since you have also a hx4700, I'd like to make another question. Wink

When I try to install winfast, nothing happens. I believe the installer was made for previous versions of activesync. I guess the only way is copying the cab file (I don't know which one, ARM, MIPS, SH3), but that will install the files to main memory. Is there a way to install them in the iPaq file store or SD card? I heard also that winfast might interfere with tomtom gps driver. Is it true?

Thank you for all your patience, David.

Andre

DavidW · Posted: Mon Jan 03, 2005 10:27 pm Post subject:

If you have to install Winfast Navigator from the .CAB file, copy the ARM .CAB file to your Pocket PC and run it on there using a file manager - it will install into main memory, but it's not a big application so I wouldn't worry unduly.

Unfortunately I don't have the BT-401, so I don't know what the rules are regarding power, but I'd be wary of connecting power directly to the HI-303MMF's connector when in the slipper - it's the same scenario as connecting power when the GPS is in a CompactFlash slot.

The problem is that you're potentially applying two power sources of different voltages to the same GPS, which doesn't seem wise!

What happens when you apply power to the connector in the slipper with the GPS inserted - does that keep the both items powered up?

David

andrems · Posted: Tue Jan 04, 2005 10:08 pm Post subject:

Yes. When the BT slipper is connected to the AC, it also powers the GPS receiver.

The only con I see about it is that might not be very healthy to the battery of the BT, since it's almost all the time being fed by AC power. Maybe it won't harm anything, I'm not quite sure about that. The battery can be removed, but it's not very practical. Anyway, maybe I'll opt for that solution.

What kind of processor is the hx4700? MIPS, ARM or SH3?

Andre

DavidW · Posted: Wed Jan 05, 2005 4:26 am Post subject:

I wouldn't worry about powering the Bluetooth slipper constantly, especially if it uses a Lithium Ion or Lithium Polymer battery. Those battery types love being charged at every opportunity; what damages them is unnecessary deep discharging.

Like all modern Pocket PCs, the hx4700 uses an ARM processor. The only non-ARM Pocket PCs run the obsolete Pocket PC 2000 operating system - all those machines are something like three or more years old now.

David

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