GWX3 using grid in radio messages that I do not have.

[CjStaal]

Where can I get the grid that the radio messages use? Instead of like BF16 they do something like 3366. I have no clue where 3366 is.

[Sailor Steve]

Those messages are for immersion only. They're historical messages that aren't really being sent to you.

The real KM grids were subdivided into subsections for more precise locations.
http://www.uboat.net/maps/grid.html

[CjStaal]

So when its saying there's a convoy and giving me a grid location, I shouldn't go to it?

[Sailor Steve]

Not if it gives a four-number grid, and especially if it doesn't give the letters...though without the letters it would be impossible to find anyway.

[Sailor Steve]

It took me awhile to find it, but here is a cool mod I use to give my exact position in my daily radio reports.
http://www.subsim.com/radioroom/showthread.php?t=207292

(You can't actually send position reports every day. I write them in my log and call it good.)

[UKönig]

BdU had a co-ordinate system based on two letters and 4 numbers. SH3 keeps it simple by removing the last two numbers.
If you were told to find grid BF1766, the first thing you have to do is find grid BF17. Then you would further sub-divide grid 17 into the same square system as the larger map. From there it is a simple matter to find grid 66 within BF1766.
Uboataces.com explains it as:
The entire ocean area was divided into large square sectors, with each being given a 2 letter code. Each sector was then divided into a 3 x 3 matrix, making 9 medium squares. These 9 squares were again divided into 9 smaller squares, making 81 grid squares for each sector. Each grid was given a two digit code, giving the system two alpha-bets and two numbers. Each of these grids were again divided into a 3 x 3 matrix, then each matrix into nine squares, so that a further 81 were formed within. Each newly formed square was again given a two digit destination. The complete system would now read as two alpha-bets with 4 digits. this made up the 'patrol zone'. Each zone covered (roughly) an area of about 6 nautical miles, squared. (6nm2).