Used to work at what was then a v busy training field. Tfc along the lines of 4 or 5 in the circuit, 2 or 3 in the stack with another on the procedure & a bunch or arrs and deps. Single freq twr & app procedural , working my bum off & get interrupted by airline c/s calling airport on same or close freq some 150 miles south of us for the wx. He's at f330 or something & blocking my freq for blummin ages.
Didn't happen just once but on many occasions. A phone call to the big airline's chief pilot helped, but crikey! what if I'd had an emergency? Wouldn't have been able to do a thing!
It's not so much the tower DOC but how strong the a/c's tx's are from altitude. HUGE safety implications that pilots need to be aware of.
ap