humm. I cant say for sure, but i think theres more too it then that. I would think the optics matter more then size. 1/4 mile isnt that much (although it might have been back then). my v940 has gone off in access of a mile before.
I thought Cobras were junk?
I had an old Cobra too, it worked as well as the Cincinnati Microwave Escorts of the day.
Back in the day, Cobra was selling re-badeged Escorts:
/\ /\ /\
yeah ive seen that before.... crazyy Cobras
Back in the day (80's) some Cobras were also rebadged Unidens. Uniden RD9=Cobra RD3160=RoadPatrol XK (radioshack).
About the sensitivity thing....alot of those old detectors can still hold their own versus X and K. That's because they had only 2 narrow bands to sweep. With the intro of "superwide" Ka, the new detectors have a lot more bandwidth to monitor.
Maxon's RD-25 was a super unit too ;^)
Cobra Trapshooter model 2100 is pretty sensitive too on x and k band.