Federal circuit court in DC is set to rule on net neutrality and appears
poised to strike it down.
http://www.wired.com/opinion/2013/11/so-the-internets-about-to-lose-its-net…
That means say byebye to internet radio. Small-scale community
netcasters won't be able to "negotiate" fees with The Bigs to get
access, even at speeds that are common today in residential broadband.
If that occurs, it strengthens the moral justification for pirate radio
and similar solutions, by a decimal place or two. In the spirit of which...
...anyone here ever hear of CONELRAD?
That was the late 1950s - early 1960s plan for Civil Defense emergency
broadcasting in the event of nuclear war. All FM stations would go off
the air, and AM stations would switch over to low-power broadcast on 640
KHz and 1240 KHz. Incoming Soviet bombers (in the pre-ICBM era) would
be unable to use RDF (radio direction finding) to navigate, while
citizens could pick up the emergency stations that were nearest to
them. Radio dials were marked with little triangles at 640 and 1240 to
make the CONELRAD broadcasts easy to find.
The signal interference issues Anthony and others brought up, must have
been addressed during the design of the CONELRAD system. If nothing
else, AM reception is more directional, and the lower frequencies
(kilohertz rather than megahertz) would reduce the problems of signal
synchronization, including during times when official announcements were
being broadcast simultaneously over all the stations in a region.
If this is the case, then blanket coverage by low-power AM transmitters
might be technically feasible.
-G
=====
On 13-11-04-Mon 2:17 PM, Anthony Di Franco wrote:
There would be a moire pattern of regions of roughly
the dimensions of
a wavelength (~3 meters) within which interference would be mainly
constructive or mainly destructive. Reception would suck or not exist
in all the regions where interference was not constructive. Then the
usual multi-path interference issues. Complicated and a good reason to
keep transmitters well spaced-out. To do this right you are pretty
much building a phased-array antenna which uses the interference
intentionally to aim the beam by varying the synchronization among the
signals from the different antennas and that is way too complicated
for this - you have to track the location of the receivers somehow for
one thing, and that's just the beginning.
On Mon, Nov 4, 2013 at 2:01 PM, David Keenan <dkeenan44(a)gmail.com
<mailto:dkeenan44@gmail.com>> wrote:
Also - this is a really dumb question but in terms of
interference, I actually have no idea what sort of interference
results when two coverage-adjacent radios are broadcasting the
exact same signal? Does it make any difference if they'd both be
broadcasting the same signal? I should remember this, since I
actually took one of those AARL tests wayyy back when (and I think
I am technically FCC licensed, at least for certain spectrums like
SSB? Can't exactly remember..i should have a certificate somewhere)
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