BU-303 Antenna Modification

**jcdillin** · 08-12-2005, 08:28 AM

Well last night was the first night in a while that I was able to get home at a decent hour and since I have since sold my garmin OEM GPS to get the UBLOX module I am currently without a GPS. So I was able to aquire a BU-303 to play with in the meantime.

After plugging it in and letting it sit for about 15 minutes inside my house I get 1 sat and it never locks onto it. So I figure well it's probably the battery problem everyone talks about. I open it up and remove the battery, same result. I get one sat and it never locks. Of course it's back apart and I start probing around.

After about 15 minutes of playing around I tested to see if the onboard antenna is a active one, whoo hoo it's a 5v active antenna! So I desoldered the stock antenna and solder on a SMA pigtail that is compatable with my trimble mag mount antenna. After that I plug it all back in and put the gps in the same spot I tested before. After about 5 minutes I get a steady 6 sat lock sitting in my house! I soldered on a CR2032 watch battery holder so it doesnt lose the postion data everytime I unplug the unit. Now at least I can keep the gps inside the car and use the antenna I was using with my garmin.

Granted not everyone is going to want to hack their gps's up to this point, but it'll do for me untill I get my ublox

here are some finished pictures, i'll post some step by step pictures when I get home later.

**meddler** · 08-12-2005, 06:03 PM

top stuff jcdillin. It has given me an idean and will probably change where I mount my GPS antenna.

**Mad Ad** · 08-12-2005, 09:30 PM

I've got something to modify the BU-303 with

Yeah, thats my modding stick

**jcdillin** · 08-12-2005, 09:39 PM

I know I know, I wanted to do that too, but I need something to get me by untill I get my ublox

**Mad Ad** · 08-25-2005, 12:11 PM

Originally Posted by jcdillin

i'll post some step by step pictures when I get home later.

methinks this is one more thing on Jerrys loooonng to-do list

yeah i know what you mean with putting up with it, ive got to put up with mine till i can get a sirf3 unit here, so far my only options are to ship one from the US or from China... no locals have it yet but my missus is due to pop over the pond in late sept so ill get one then, still thats a month away, another month to resist modding the bastd thing into a zillion tiny pieces.

**Cris** · 11-11-2005, 08:05 AM

What happened to the step by step pictures Jerry?

**jcdillin** · 11-11-2005, 10:26 AM

of me smashing it? will be here this weekend since I now have the ublox.

**Custommx3** · 11-11-2005, 10:53 AM

Ever hear of a BU303 that the data is just a bunch of garbage instead of NEMA data?

**jcdillin** · 11-11-2005, 11:57 AM

sounds like the usb converter took a dive, or somehow the port rate was changed. If the port is opened at anything other than 4800bps you'll get only garbage data.