Why is air traffic control radio comms so poor?

Question

I have been following Blancolirio's videos about the DC mid-air collision and every time I hear ATC audio I am shocked that these are people who communicate professionally in a safety critical field. In particular in today's video[0] there is a lot of audio comms between the tower and the two aircraft (around 6:30 in this video). I am a native English speaker who consumes a lot of American content, so it's not about my own comprehension or deciphering American accents.I literally would have no idea what these guys are saying if there weren't subtitles. Even with subtitles I struggle to keep up.1. The audio quality is extremely poor. I have to believe that the receivers in the tower and on the aircraft must give a better quality than this. I find it impossible to believe this quality of audio would be acceptable in 2025.2. More importantly, the pilots and ATC folks speak excessively quickly and do not enunciate at all. It almost feels like they are intentionally speaking in an incomprehensible way. I'm sure some pilots will come and say that this is just how they speak in the business and you adjust to it, but to me it feels unacceptable. I have had jobs where I spent a lot of time on CB and RT radios and we intentionally speak clearly and enunciate. We do not slur or blur words together.What is going on here?[0] https://www.youtube.com/watch?v=n9mAUks0krI

p_ing · Accepted Answer

You're hearing a ground based receiver from who knows how far away with who knows how strong of a reception. You're not hearing what a pilot/ATC hears.

binary_slinger · Answer

> 2. More importantly, the pilots and ATC folks speak excessively quickly and do not enunciate at all.
Multiple aircraft’s one frequency. Need to speak short to allow other potentially higher priority calls. Also take a moment to read: https://www.faa.gov/air_traffic/publications/atpubs/fs_html/...
Of course in practice there are deviation's from the phraseology.
I do agree the DC ATC audio is very poor. Not all ATC communication is that poor. And often it is quite clear especially once you get use to how radio calls are made.

teovall · Answer

Aviation still uses AM radio which is more susceptible to noise than FM or digital modes but it does so for two very important reasons.
The first is that, with AM, if two or more people are transmitting on the same frequency at the same time, they can all still be heard. With FM, the strongest signal will suppress any weaker signals and only one signal will be heard.
The second is that even very weak AM signals have the chance to be received and understood. The human ear is very good at picking out human voices from noise. Weak FM signals just drop out completely.

slater · Answer

i think it's not quite as bad when it's live, through headphones etc.