> Back in the late 60's I heard an LDE that had about a 10 second delay and
> was a repeat of everything I and the station I was working sent for about
> 3 minutes. We were both pretty freaked out by it. I've heard others,
> both longer and shorter delays, but nothing like that. I wish I'd
> recorded it.
>
> 73, Zack W9SZ
OK, let's think about it. Radio waves travel at the speed of light,
and a 10 second delay would translate to about 1.86 billion miles
before it was again heard. That is approximately the distance to the
Planet Saturn, or assuming an Earth orbit, a complete round trip 7,410
times.
You could assume a large dish antenna with 50 db of gain, and a loss
of 1 db per trip, and the signal would be in the mud on the 148th
trip. That would leave approximately
7262 more trips around the Earth until it was received and heard. Not
to mention the vast improvements in receiver noise floor in over 40
years.
Tape recorders have been around for a long time. So has elementary
math. Recorders change with time, math doesn't.
In no way do I mean to doubt Zack's word about it, but it simply is
not possible as an LDE.
On my own recollection of received LDEs the longest I ever heard was
the letter B of my call at about 35 wpm, and that was also on 10
meters.
I leave it to someone else to figure the gain and power needed to
bounce a HF signal off Saturn, which is actually twice the distance.
Even our best orbiting telescopes are not capable of that.
73
Ed
---------------------------------------------------------------
The world's top contesters battle it out in Finland!
THE OFFICIAL FILM of WRTC 2002 now on professional DVD and VHS!
http://home1.pacific.net.sg/~jamesb/
---------------------------------------------------------------
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
|