"-.-. --.-" wrote in :

... you readers
what have to suggest about height and un-un if you have to build a
random vertical to cover 80-6 meters with a decent efficiency ??

Most of us would understand efficiency as you have used it to mean the
ratio of radiated power to antenna system input power.

An unloaded monopole system that is long enough to be reasonably efficient
at 80m (say 13m) will have a radiation pattern that is most unattractive
at 6m where you would depend on low angle performance for most contacts.

Owen