On Nov 26, 4:49 pm, "tom k in L.A." wrote:
- what are those jet-engine type sounds
- i hear on certain frequencies?
- it's not static, it's a tuned signal,
- but sounds like a jet engine.
- thanks.

TKinLA,

"Jet Engines" Sounds are usually described as having
a High Whine and Loud Roar.

The more common "Aircraft Engine" {Airplane} Sounds
that Radio Listeners say that they Hear are more like
the Sounds coming from a Propeller {Prop} Engine with
a Medium Pitch with Constant Noise and may be some
Thumping {low level sound modulation}.

-IF- These Sounds are Sharply On-Frequency +-5 kHz
they can be some from of Non-Voice/Music Transmission
or possibly Radio Jamming of that Broadcast Frequency.
http://en.wikipedia.org/wiki/Radio_jamming
http://en.wikipedia.org/wiki/Radio_jamming_in_Korea

"Digital Hash" Sound is more of a 'White Noise' Sound
is a Constant Across the Spectrum High Noise Level
which extends for 20 kHz or more around any frequency.
http://en.wikipedia.org/wiki/White_noise

To me the Chinese Opera Music being Broadcast by China
Radio International (CRI) from China (PRC) on Shortwave
was a form of Jamming.
http://en.wikipedia.org/wiki/Chinese_opera
http://en.wikipedia.org/wiki/Music_o...#Chinese_Opera

~ RHF