I assume an instruction from ATC sent via CPDLC will be received only by the aircraft for which the instruction is intended, and if so isn't it the case that a vital component of situational awareness is lost if , say aircraft A is instructed to turn/climb/descend etc and adjacent aircrafts B, C, D etc cannot now know what A is doing?
As an aside, I well remember listening in on HF and being astonished how many attempted calls were unanswered, presumably due to poor propagation.
'Santa Maria, Santa Maria Reach XYZ position over'
30 seconds later...
'Santa Maria, Santa Maria Reach XYZ position over'
30 seconds later...
'Santa Maria, Santa Maria Reach XYZ position over'
30 seconds later...
'Reach XYZ nothing heard, out'.
(Reach btw I gather was commonly used as a USAF callsign.)
On the other hand, one morning 7 am here in the UK I heard a flight calling ATC somewhere in South America (Paramaribo I think) with surprising clarity on a Yeasu FRG7700 with random wire aerial (antenna!).
Last edited by Ant; 31st Aug 2019 at 20:02.