I'm not well informed on this subject, and I sure don't know what causes the multi-path condition even at longer ranges. However, for sometime I've felt this was what was going on when the locals here were able to communicate with stations around...up to a 100 mile and greater range without notable DX working. I have even suggested to Bob that might be what he experienced when he was able to communicate with his buddy at a distance on the coast, only when they were both using their Vector hybrids and no other antenna.
I think all of the CB vertical antennas I have present the necessary lobes, angles, and gain for this to work, but I'm not sure how close up this happens.
I think Bob noticed this with several stations on one of my videos, but these stations are around the 30-40 mile range, so maybe it does happen this close.
I too have an idea of the signal peaks from my buds too, but much more than conditions are going on here that affects their signals. These guys maybe unusual operators, in that they have multiple radios, amps, beams, and vertical antennas, and sometimes they change stuff just for the hell of it.
MrS, if your buds were so lucky to have a variety of gear like this, could this maybe account for some of the difference that you never see at your station?