Despite the availability of SATVOICE calls and CPDLC over satellite, HF voice communications are still widely used over oceanic and remote areas.

Why? Because they are more affordable, independent of external communications providers, and, of course, because you always need two different long‑distance communication systems to maximize safety.

Believe it or not, HF bands are still very much alive. For those interested in exploring the topic, I’ve put together this short guide, including band allocations and basic HF propagation guidance.

Note: Some frequencies may be outdated. Gathering all this information from so many AIPs is not easy. As far as I know, there is no official public site that compiles all published frequencies. If you have updated information, I’d appreciate it if you shared it.

The airspace is divided into manageable portions, each portion is called a "control sector" and there is an air traffic controller in charge (sometimes may be a tandem, but just one of them transmit via radio).

Along the flight control is transferred from one controller to next at the sector border, however, transfer o communications allways preceed.

There is a simple rule to know: 

ONE FREQUENCY - ONE SECTOR - ONE CONTROLLER

Approach airspace & comms follow similar rules, the main difference is that sectors are smaller and much more dynamic. Approach procedures fully depent on the operational runway and that depends mostly on meteorological conditions, so may be prone to frequent changes.

A complex airport requires many air traffic controllers working as a perfectly coordinated team. Each one is in charge of one specific function, ground area, or runway. Then each air traffic controller has an unique VHF frequency to communicate with.

They way controllers organize and VHF frequencies are used may be different from one airport to another, local AIP needs to be consulted. At LEMD, the spatial assigment is fixed, each controller manages a runway, no matter the runway configuration (departures or arrivals).

This is another example of a complex airport, including approach information.

The ATC organization at LEPA is somewhat different: controllers are in charge of a specific role (departures or arrivals), then if runway configuration changes, the controller changes the frequency (a may even the seat at the control cab).

G.A. aerodromes have simple configurations and tipically use just a couple of frequencies (TWR and GMC). Despite that, some of them, like LECU, are very busy: Flight schools, public services, military, private, sports and recreational aircraft share the same aerodrome (and airspace) - Not easy for the ATCOs!

There are also military aerdromes and all the operational information is open and published on the AIPs.

Configuration varies, however, most of them are simple: one runway and a very big APRON. Getafe Air Base (south of Madrid) is a good example.

Be aware that while TWR control service is provided by own military ATCOs, approach service is provided by Madrid ACC (civil).

The so called "Aeronautical Mobile Service" by ICAO, comprises controller to pilot direct communications as well as the "Aeronautical Broadcast Service", which is just unidirectional. This in fact is a functional part of the Information service, but automated. The ATIS broadcast terminal area information, associated to an airport, while the VOLMET broadcast wide area meterologial information. Than explains why there are so many ATIS and so few VOLMET.