[ntp:questions] CHU Public Notice : http://inms-ienm.nrc-cnrc.gc.ca/time_services/shortwave_broadcasts_e.html

David L. Mills mills at udel.edu
Thu Dec 14 05:10:59 UTC 2006


hjsjms at cs.com

The ITU has allocated the band 7300-7450 kHz for broadcasting in all 
three regions of the world. The band 7450-8100 kHz is allocated for the 
fixed/mobile services, so Canada could in principle move CHU to some 
frequency in that band. North of 8100 kHz are huge blocks of maritime 
and aviation channels. However, in typical ugly American fashion, that 
band is allocated by the FCC in the US for broadcasting (47 CFR Part 
2.106). Even now, CHU has to contend with loudenboomer splatter from 
cochannel and neighboring channel broadcasters. Moving north of 7450 kHz 
might have the same problem, and that from south of the border.

One alternative might be to move CHU south of the 40-meter amateur band. 
There is a 6765-7000 kHz band allocated for the fixed/mobile services. 
However, the FCC considers that an ISM band, so various kinds of evil 
emitters are sure to be found. Tonight I found a S9+20 dB religious 
program on 6855 kHz broadcasting from Florida, no doubt registered as an 
ISM emitter. Don't get me going on Part 15 and Broadband over Power Line.

The dillema CHU faces is quite serious. The ITU has allocated 10 kHz 
channels at 2.5, 5, 10, 15, 20 and 25 MHz for standard frequency 
broadcasting. However, shortwave broadcasters are camping on +-5 kHz 
carrier spacing on 5 MHz at least, so their sidebands sometimes clobber 
the WWV transmission, contrary to ITU and FCC rules. There is no other 
frequency that is protected from the broadcasters or vested interests.

The unvarnished fact is that CHU has been a valuable service in the 
eastern US and Canada where WWV signals are often weak and unreadable. 
And, sad to say, WWVB service at 60 kHz has become seriously degraded 
due to noise pollution via the power lines and uninterruptable power 
sources (UPS). My experience with the NTP audio demodulators for WWV and 
CHU suggest that they may in fact become the preferred alternative after 
GPS, which has its own antenna issues.

Dave

hjsjms at cs.com wrote:
> Does anyone know how the definitions of a broadcast and fixed signal
> differ?  It sounds like ITU is expanding the number and kind of
> stations that can use that frequency.  Implicit within that decision is
> that the time signals from WWV on 5 and 10 mhz could fill the void
> which may not be the case.
> 
> I wonder what the process of re-doing the CHU license for the 7335
> frequency involves and whether they may find themselves competing with
> other signals.  Best solution might be to shift to a nearby frequency.
> 
...>

> 
> 




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