I have just about given up.
For the life of me, I can't keep a consistent angle on any stone, diamond plate or steel small enough to carry with me in the field. I end up getting it sharp, then with the next stroke wiping out all of my progress. Even with a bench-mounted stone, I am one of the unfortunate "sharpening-disabled" that never gets the results others brag about.
When hunting, I either carry more than one knife with me or use a replaceable scalpel blade knife.
I did pick up a nice drop-point skinner with a S30V blade, but haven't had a chance to try it out yet. I figure that should last me through the season, except in exceptional circumstances.
How do YOU handle this problem?