What is a clear channel station?

It's now an obsolete term ...


Hardly.

Clear channels a 540, 640-780, 800-900, 940, 990-1140, 1160-1220, 1500-1580.

Local channels a 1230-1240, 1340, 1400, 1450, 1490

All other channels are Regional channels.

It's clear that the most channels are clear channels.

The popular meaning of the term may have changed, but the legal definition
hasn't.

There is at least one Class I station (either Class I-A or Class I-B) on every
clear channel, and all such clears are clearly identified in the NARBA and Rio
treaties as to power and antenna efficiency (although for some Mexicans, the
antenna efficiency may be bogus).



Also known as single stick stations, as their antennas use only a single tower
and radiate omnidirectionally.


In general, Class I-As are single-stick.

But, there are as many Class I-Bs which are single stick as there are Class
I-As which are DA-1.

Class I-As which are or have operated DA-1: 660, 870, 1030, 1100, 1580.

Class I-Bs which operate ND: 680, 810, 850, 940, 1070, 1550


Also, there is a single stick Class II-B on a clear channel where the Class I-A
is DA-1: 1580

And, there is a Class I-A which protects a Class I-B: 1540, protecting KXEL,
which is a Class I-B.

Finally, there are Class I-Bs which protect Class II-Bs: 710 and 1510.