Strange sounds over Boscombe Down

Hello,

I know this is a bit woolly, but i live a matter of miles away from RAF Boscombe Down.

Over the decades there have only been 2 instances where what i perceive to be fast jet aviation activity has made me prick up my ears (for example the sound of engines is odd, or does not behave the way you might expect).

Most of the stuff that flies around is on circuits and very predictable, or on a rapid climbout.

In the past 2 days there has been an aircraft flying around at night which has an engine sound a bit like a quiet Hawker Hunter (you know- the whine rather than roar that its engine generates).

This aircraft was airborne last night at 4am and the engine sound was not very loud and lasted for perhaps 10 seconds (from fading in to fading out). It started fairly gradually and cut out very suddenly.

I am no expert on the acoustic signature of all possible engine types here, but its the way the sound generated behaved, that caught my attention.

I remember a similar incident around 1994/95.

Does anyone have any thoughts or expertise that might help me?:o:confused: