The Idea
I wanted to improve the original POLAR design, after a few comments, a few hunts, and a few more ideas. So, the goal here is to make the computer display magnetic bearings, not just from the front of the vehicle. Also, I wanted to improve the quality and type of information displayed.
GPS
The only way I could figure out how to get reliable magnetic heading information is from a GPS. So, I have added a serial in, on pin 3, or A4. The program will scan for the $GPRMC sentence, and when found, will parse out the speed, heading and magnetic variation information.
The heading information is then inserted into the serial data out, when the speed is greater then 3 mph.
S-Meter voltage
After a number of installations and experiments, I have discovered that not ever S-Meter circuit delivers +5v at full scale (gee!) - So, I have added a adjustable reference voltage section and made it possible to make anywhere from +.4v to +5.0v be full scale deflection of the on-screen S-Meter. Of course, you can still use the program controls to adjusted the displayed range of the S-Meter.
APRS
Since I play with APRS quite a bit, and now we have the magnetic bearing of our antenna, I decided to make an option to output Agrelo-format DF data to APRS. If you short an on-board jumper, the serial data out becomes the standard APRS extension of %bbb,q which can be fed directly into APRS. I have mounted a switch on the outside of the metal box so I can switch formats at any time.
Program
Now I have updated the hardware, on to the display program. The display is only slightly changed, with accommodation of the additional bearing data on the left. Also new in the program is the ability to save the state, or the on-screen settings for rapid changes or filters. Press CTRL-F?, using any of the function keys at the top of the keyboard, to save the state. Then, you may just hit the F? function key to 'recall' that state.
Also, the other big change is the waterfall display - press M for mode and look at the display!!!!
POLAR.EXE
Program file (NEW version 2.5.7) 
README2.TXT
Readme file for POLAR with keystroke definitions
As always, I am very interested in hearing suggestions or comments on how to improve the software (or anything, for that matter)
Windows CE!!!
I now have a working version of the POLAR2 software working on my Journada - the program is written in embedded Visual Basic and runs on any Windows CE device - please let me know if you would like to play with it!!!
How to get it
Contact me. I have a kit that includes etched, plated-through PCB board, programmed chip and all components for $25. Since this boards have an identifiable problem, I have fixed, assembled and tested every one.
Errata
Looks like Mr. Murphy will always be with me - there is a fundamental flaw in the boards I had made. Seems like the +v and Ground got switched on the PIC chip (again). To rectify this, simply cut the two traces that lead to pins 1 and 8. Pin 1 SHOULD be +v, not ground, so place a small shielded jumper to the trace running along the top of the board - probably the most convenient place to jump to would be the top of R3. For Pin 8, which should be ground, run a small jumper to the left, which will go to C4 and J2. I apologize for any inconvenience for this mistake - and thanks again to Bill, WD6ADM, Jess, W4PQK, and Bob WA6EZV.
Future
There is a lot of ways to improve this concept, and I will be updating this page as I work new things out. Please let me know if you have an idea on how to make this better, or how to win more hunts!!! I'm also working on a touch screen version, for use on the Citadel type computers - I'll post it here when it's finished.
Acknowledgements
I would like to thank Bill Schroeder, WD6ADM and Jim Kasee, KB8UEZ for help
in identifying mistakes in the schematic. Also thanks to Jess Hancock W4PQK
for his trials and tribulations with this project - as always, two or more heads
are better than one!!