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U2 Erratic Timing - some detail
"David Atkins"
I hope the detailed description of the erratic behaviour, recorded below,
will give an indication to someone of the cause. My Trimble Jupiter modules refused to register [both of them]. So did my Sure Evaluation kit. Even though they all work perfectly with several GPS evaluation programmes. An EM-406a arrived from Germany this morning, and I have tried everything I have seen suggested in the past week or so. This is how it goes: I have Frame set to 10 I have Start set to 04 GPS Baud is 04800,01,1,8 Use GPS On Inv GPS On -- yes, I know, but nothing works with it off Frq set to 10.140.198 Locator is rubbish Set Time is rubbish Switch on at 16:00:04 Locator sets correctly to IO91, time sets correctly to 16:00:04, Sys Frq remains un-modified; Time them increments in two-second steps every second -- 06, 08, 10, etc -- until it reads 16:03:50, when it resets itself to the correct time (16:01:26, say). Then count up at double speed until it gets to 16:03:50, when it resets itself to the correct time, and starts counting up at double speed again. This happens over and over until the time really is 16:03:50, when it counts on up to 16:04:00 and starts transmitting. Of course, it counted at double speed, so the transmission starts at about 3 seconds before the start of the even minute. But the transmission itself is at normal speed, so I can decode it on another rig. After the transmission, we go through the double speed until the clock reads 16:13:50, then the reset etc cycle goes on until the transmission at a couple of seconds before 16:14:00. Does that seem reasonable? OK, so how do I cure it? I have the RX data pin of the module tied to Vcc, and both ground pins are connected to 0v. Beyond that, I have tried pull-up resistors (10k ohm) and pull-down resistors on the pps line and/or the TX data line. No change. ?help? David G8XBZ |
Barry Chambers
¿ªÔÆÌåÓýOn 23/05/2013 21:50, David Atkins
wrote:
?David Your GPS experiences pretty well match mine, except that I'm using a EM-406A GPS. -- 73 Barry, G8AGN |
"TONY_VOLPE"
--- In QRPLabs@..., Barry Chambers <b.chambers@...> wrote:
Me too. My EM-406A is the same. |