[sudo-discuss] Radio: Internet radio is about to get borked; just say CONELRAD.

[Steve Berl]

According to http://en.m.wikipedia.org/wiki/CONELRAD the stations on other
frequencies than 640 and 1240kHz shut down and the stations that normally
broadcast at 640 and 1240 took turns round robin style transmitting.

So nobody switched frequencies or went to lower power.

As someone who has actually navigated a boat by AM band RDF I can say it
would be very frustration if the transmitters kept moving around. It would
definitely make it harder to find targets in the pre-GPS world.

Too bad about net neutrality. This might really suck.

Steve

On Monday, November 4, 2013, GtwoG PublicOhOne wrote:

>
>
> 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-neutrality/
>
> 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 at gmail.com<javascript:_e({}, 'cvml', 'dkeenan44 at 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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>

-- 
-steve
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