There should be other ways to obtain the Field notes.

[RyuDragnier]

Dabog's & Lyon's notes have a 100% drop rate from their duels. Save yourself the headache and go kill the duels; the notoriety system guarantees you'll get into them after enough attempts.

Assuming you don't have constant lag/latency issues or can react fast enough. I have a friend who has both of these problems, and they were forced to camp the spawn for Murder, Death, Kill and spam Castrum for a week straight until they got both.