Talk:CHU (radio station)

Message from Raymond Pelletier
E-mail I received from NRC regarding possible shutdown of CHU:

About the New Messages on CHU – October, 2006

The added messages on CHU are:

“On April 1, 2007, CHU needs to stop operating, change frequencies, or re-licence. Contact radio.chu@nrc.gc.ca or mail CHU Canada K1A 0R6,” and

« En avril 2007, CHU doit soit cesser ses opérations, soit changer de fréquence, soit renouveler sa licence. Contactez radio@chu.cnrc.gc.ca ou écrivez à CHU Canada, Conseil national de recherches, K1A 0R6. »

This outreach is to collect information from users of CHU to help shape recommendations concerning what should be done concerning changes to CHU that will have to be in place by April 2007.

In April 2007 the licence on 7.335 MHz will have to be modified to reflect changes on the status of the band allocation by the International Telecommunications Union. This frequency has been changed from “fixed service” to “broadcast”. (The ITU decision does not affect the frequencies 3.33 MHz and 14.67 MHz.) Some alternatives are:


 * Re-licencing just might be possible, calling the 7.335 MHz a “broadcast”.
 * It is also possible to stop using that frequency (the most useful of the three we use). Stopping one signal is the easiest solution but could create problems for some clients who are counting on this particular signal.
 * Change the frequency from 7.335 MHz to a nearby fixed-service frequency. It would need some investment from our part in new hardware and in manpower. It could also create problems for clients, and likely not all radios will be able to tune to the new frequency.

To be seriously considered, any of the above alternatives will need to have a zero-based budgeting justification prepared, comparing it against the least expensive alternative of closing CHU entirely. CHU is entering a phase where major investment in new transmitters will be required if it is to be kept operating. In the absence of input from the CHU user community, concerning the importance of CHU’s contribution in the modern world, this last option is an inescapable recommendation.

The CHU code is also used as a radio clock, which can be used as a reference clock for an NTP time server. Software drivers have been written that can obtain the date and time from the code and that tune a digitally tuned radio to one of our 3 frequencies, to get the best signal. Users of this service generally don’t listen to the audio broadcast. So we cannot gauge the usage by sending this announcement.

Please, if you know of anyone using CHU but not aware of the possible changes to its frequency usage, let them know and ask them to contact us. Also if you have an important use for CHU signals, please tell us how you use our signals.

Be assured that we will try our best to maintain the CHU service as it is, keeping the three frequencies as they are. Thank you for your support. Raymond Pelletier

--  Denelson83  21:45, 18 October 2006 (UTC)

Further message from Raymond Pelletier
Tuesday, March 13, 2007 6:45 pm

Thank you for your concern for CHU. We have had permission from the CRTC to continue transmissions on 7.335MHz, in the present mode of operation. So operations will continue on all 3 frequencies as usual.

73's

Raymond Pelletier

-- via  Denelson83  23:37, 14 March 2007 (UTC)

I would like to add something here
CHU clashes with us shortwave station whri -world harvest radio on 7.335 MHz CHU had the frequency first

--spiddy 00:48, 25 April 2007 (UTC)

CHU to move frequency
From 7.335 to 7.850 At Midnight UTC 1-1-09 Peterparker3000 (talk) 22:11, 11 December 2008 (UTC)

Antenna coordinates
As with WWV, WWVB, and WWVH, CHU has multiple antennas at slightly different locations. Using Bing Bird's Eye, there are 3 of them, several hundred feet apart. Someone should improve the table of antenna coordinates to show this, as in Wikipedia's articles on the other 3. agb — Preceding unsigned comment added by 143.43.206.65 (talk) 18:15, 9 August 2012 (UTC)
 * We don't know which antenna radiates which frequency, though. --  Denelson83  20:42, 9 August 2012 (UTC)

Audio file details / correction
The first audio file from User:Xenon54 is quite useful to me for a Bell 103 softmodem project I'm working on, but I think there might be an error in the caption. The decoded data stream from second 38, in hex, is 36 52 10 52 83 ; after nybble-flipping and digit grouping, that becomes 6 235 01:25:38 where the day of the year is 235. This corresponds to November 21, 2010, not November 23 as is stated. The time is also 01:25 instead of 01:26 ; the voice signal says 01:26 but that is because it comes at the very end of the minute and serves to label the next minute's transmission.

This is of very minor importance but it might serve to anyone else using the audio file for this admittedly unusual purpose.

--Kulp (talk) 19:21, 17 November 2012 (UTC)
 * Did you decode the data bursts in seconds 32 through 37 and 39 to confirm that it was actually November 21? --  Denelson83  20:47, 17 November 2012 (UTC)


 * I decoded second 33 (and its redundant bytes) and it agrees with second 38 (and its redundant bytes). Prior to mechanically decoding seconds 38 and 33, I had decoded second 38 manually, and all decodings agree on day 325. Eventually I will have all of the cases decoded and can update this page with more evidence. --Kulp (talk) 21:02, 17 November 2012 (UTC)

Tone derived from carrier frequency?
These two statements seem to contradict each other:


 * In 1938 ... The 1,000 Hz tone imposed on the carrier was derived from the quartz oscillator that determined transmit frequency
 * Until 1959 the carrier frequency, tone frequency and second pulses were derived from independent sources

So I wonder which one is correct. GA-RT-22 (talk) 13:09, 16 October 2023 (UTC)