RE: [HCDX] Mediumwave echo ?

["Charles Hutton" <charlesh3@xxxxxxx>]

John:

A one-hop (up and down) satellite delay is about 250 ms since:

- it's 22,500 miles up and 22,500 miles down for a total of 45,000 miles
- speed of light is 186,000 miles per second

So it's about 1/4 of a second delay, and I have no idea how the 450 ms echo
was generated other than wild ideas like Rebelde sent it up on 1 satellite
and a regional net put it up again on another satellite and finally (!) the
900 KHz outlet put it out.


Chuck

-----Original Message-----
From: hard-core-dx-admin@xxxxxxxxxxxxxxxx
[mailto:hard-core-dx-admin@xxxxxxxxxxxxxxxx]On Behalf Of J999w@xxxxxxx
Sent: Tuesday, October 08, 2002 9:59 PM
To: hard-core-dx@xxxxxxxxxxxxxxxx; amfmtvdx@xxxxxxxxxxxxxxx
Subject: [HCDX] Mediumwave echo ?


Hello all,

I was reviewing a recording I made of Radio Rebelde, Cuba from October 3,
2002 at approximately 0100z on 900khz and heard something interesting. What
was initially a normal sounding signal, developed an echo that lasted for
about 3 minutes, then dissapeared, reverting back to normal again.

Using CoolEdit software, I measured the delay to be 450milliseconds. I
wonder
what could have caused this delay ? Did it originate in the transmitted
audio
such as a satellite delay, or is it a propagation phenomenon? Reading
through
the literature, I learned that the longpath propagation delay in on the
order
of 130milliseconds.

I have a short audio clip at: http://members.aol.com/j999w/DX

Any ideas?

73!

John Wilke
WB9UAI
Milwaukee
R71a and vertical

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