I listening between 5.615mhz and 5.620mhz AM. There is definate
conversation. One side seems to be confirming numbers and other things
using the phonetic alpabet. The signal is varies between 6 and +20 here is
S.E. UK. There is no set pattern to the length of conversation (around 10
secs) or the length of time between them. The conversation occasionally ends
with a "message received" and several tones. The strange thing is that the
person on the other end of the conversation seems to be on LSB and it is
very hard to make out what they are saying.

I would normally have said it was HF aicraft comms but it doesn't sound
right. Maybe it is, but there seems to be no mention of flight levels etc...

MC