Couple weeks ago, I bought an unbuilt* 40 meter Rockmite from a Zedizen and threw it together in 3 hours, beginning at 9 PM. (I don't USUALLY build kits that late at night!) Anyway...I already know how good the Rockmite's ears were...the sort of low noise clarity that only a DC receiver can deliver.
Anyhoo.....Field Day was one of those "Life's too short for QRP" weekends....as is every Field Day up here. Day AFTER field day, I worked gobs of stations with my 1/2 watt Rockmite and a "tatty bit of wire" I have out in the back yard.
I've come to the conclusion that the ionosphere can only handle a certain number of signals....which is why it never works on Field Day.
Now you know.
*No...he didn't UNBUILD it....he just never built it. Just so ya know.