I can see it now... Ultimate 3 including a real time clock like this one... Tell the new U3 your 10 character grid and watch it keep the transmitter on time...
Paul KE7HR
toggle quoted message
Show quoted text
--- In QRPLabs@..., Hans Summers <hans.summers@...> wrote:
All
As some of you know, I have what I call a "GPS Simulator" which is an
ATmega88 I programmed to send a NMEA string with the $GPRMC sentence, and
it also has a realtime clock which updates correctly in the $GPRMC, and
produces a 1pps signal output. Using this I can model different settings,
baud rates, and 1pps pulse widths.
From the comments on which GPS modules worked and which didn't, there
seemed to be a consensus opinion that GPS modules having very short
(microseconds) pulse widths on the 1pps signal, do not work properly in
v2.02a. So I have set my simulator with a very short pulse width, less than
1us. Using this setting I can see the seconds jump sometimes in 2 second
jumps. So I am able to reproduce the same problem some GPS modules show.
Next I printed out my code and stared at it all week on the train to and
from work. I came up with a strategy for fixing it. This evening I tried
the strategy. It works! In my simulator at least! Everything is ticking
away here nicely with 1 minute frame, message "E" in FSK/CW with speed 006,
GPS on, and < 1us pulse width. Heartbeat is beating nicely and 125MHz
calibration has occurred, as have time setting and Maidenhead locator.
I will now send a v2.03 chip (as it will be called) to Eddie G3ZJO (proud
Trimble owner) and Andy G0FTD (UP502 GPS) and Tony G0BZB (EM406). If you
three can try it and it works on all three then I think this will be
excellent progress indeed, maybe finally the Ultimate2 GPS issues will be
over and we'll have widespread compatibility with most GPS modules.
Fingers crossed...
73 Hans G0UPL
