BU-303 extremely slow updates...power/interference?

**Fej** · 02-25-2006, 04:24 PM

Hi all,

I have recently put together a car PC system, and I'm having problems with the GPS unit. I opted for a BU-303, the little GlobalSat USB GPS mouse, because it was cheap. The system board I have is a Matsonic MS-CLE266-F, actually Flex-ATX, not ITX, but it gets the job done, and one of the $150 TM-868 generic brand 8" touch screens off eBay (which I'm actually very happy with). I'm powering the whole thing with an M2-ATX DC-DC board.

As for peripherals, pretty much everything is USB:

Bluetooth v2.0 dongle
Zonet ZEW2500P 802.11g wifi adapter
Generic number pad for easy control w/o full keyboard
Mini keyboard/trackball mouse combo
Input control for the touch screen
BU-303 GPS unit

Everything worked like a charm for a very short time. Now, everything works great except for the GPS. I've got iGuidance installed, as well as the GPSInfo utility, and both exhibit the same behavior. What happens is the data coming from the GPS unit is extremely slow or non-existent. When I do the COM port scan in GPSInfo, it never finds a "GPS Receiver" like it's supposed to, only occasionally finding anything besides "No device" (there is a third option, something like "No GPS attached" or something that comes up sometimes). If I leave it plugged in and iGuidance running, every few minutes or so it receives an update, but only a single data point, usually not enough to update the position on the map. As far as I can tell, this isn't a satellite lock issue, because I would at least be seeing lots of constant data updates even if my position wasn't changing. Please correct me if this is not the case.

Originally, I suspected the GPS unit itself, but I took it out of the car and plugged it into my laptop inside the house, and although it doesn't lock onto any satellites inside, the data stream is constant and fast like it's supposed to be. So the GPS unit is still functional. I'm not sure what the deal is.

I thought maybe there was insufficient power coming from the USB port on the carpc MB, and I even went so far as trying a powered USB hub running off an inverter in the car to see if it would help, but it didn't change at all. Is there something I should be looking for beyond that? Some high wisdom that a poor noob such as myself is unaware of? This is a brand new install, and I have no idea why it should have stopped working so soon (or at all, for that matter). I could try a complete OS reinstallation, but that would be a pain. If I can fix it without that, I'd be very appreciative.

Thanks all,

Jeff

**Marvin Hlavac** · 02-25-2006, 06:09 PM

No idea what the problem is, so I'm just guessing here... Just for testing purposes try unplugging all unnecessary USB accessories from your PC, then plug only your GPS receiver (without any extension cable attached). Place the GPS receiver on the roof of your car and try it then. (Use only one GPS application at one time.)

**Fej** · 02-25-2006, 09:34 PM

Thanks for the tip. I tried doing something similar before, but not all the way down to nothing, and I didn't get rid of the extension cables. Having now done that as well, I have to suspect something about the extension cable. I unplugged everything as you suggested and uninstalled all of the drivers for good measure, then plugged the GPS back in. Lo and behold, it works. I plugged everything else back in one by one, and it continued to work. However, when I tried plugging it into via the extension cable (which is 10 feet long, really overkill for this application), the system spontaneously rebooted. Perhaps the line loss is really high for that length of cable. I've rearranged everything so I can use it without the extension, but it's not quite as pretty as I'd like. I might try a shorter one (perhaps 3 feet) and see if that works.

Thanks again!