RSID: <<2026-07-30T23:31Z MFSK-32 @ 9265000+1500>>

 

Welcome to program 460 of Shortwave Radiogram.

This is Al Holt in Alachua, Florida, USA and
Tony Pavick in Hope, British Columbia, Canada
sitting in for Kim Andrew Elliott.

Here is the lineup for today's programme, in MFSK modes as noted:

  1:33 MFSK32: Programme preview (now)
  2:44 MFSK32: WWV & the History of Time/Frequency Stations
  8:01 MFSK64: The History of CHU
10:57 MFSK64: WWV, WWVH, WWVB, WWVL, & CHU QSL cards
28:57 MFSK32: Closing announcements

 

Please send reception reports to radiogram@verizon.net

And visit http://swradiogram.net

We're on Bluesky now: SWRadiogram.bsky.social

And X/Twitter: @SWRadiogram
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Standard Time and the Importance of Accurate Time

Standard time is the synchronization of clocks within a
geographical region to a common reference rather than local solar
time.

During the nineteenth century, expanding railroad and steamship
networks made accurate scheduling increasingly important. Great
Britain's railways adopted Greenwich Mean Time in 1847, while
railroads in the United States and Canada introduced a five-zone
system in 1883. On November 18th of that year, it was agreed all
United States and Canadian railroads would readjust their clocks
and watches to a telegraph signal from the Allegheny Observatory
in Pittsburgh at exactly noon on the 90th meridian.

Standard time became U.S. law with the Standard Time Act of 1918,
which also established daylight saving time.

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Time touches nearly every part of modern life. Whether you're
checking your phone, navigating with GPS, making an online
purchase, or watching a live sporting event, you're relying on
clocks that are synchronized with remarkable precision.

Behind those clocks is Coordinated Universal Time, or UTC, the
international time standard maintained by a network of atomic
clocks around the world. Time is distributed by satellites, the
Internet, telephone networks, and radio transmissions, allowing
devices everywhere to stay in step.

Accurate time is far more than a convenience. Telecommunications
networks depend on precise synchronization to move enormous
amounts of data. Electric power systems require accurate timing
to monitor and balance the grid. Financial markets record
transactions to the millisecond, while scientific experiments
often measure events in millionths or even billionths of a second.

For radio enthusiasts, accurate time has always been close at hand.
Since the early twentieth century, stations around the world have
transmitted standard time and frequency signals that anyone with
a suitable receiver could hear. These broadcasts not only set
clocks but also provide precise frequency references and a
convenient way to judge radio propagation.

Many countries have operated time and frequency stations over the
years. Some have fallen silent as Internet time services became
widespread, while others continue to broadcast around the clock.
Their familiar ticks, tones, voice announcements, and digital
time codes remain valuable to laboratories, industry, radio
amateurs, and shortwave listeners alike.

We'll take a closer look at two of the best-known CHU, WWV (WWVH,
WWVB, and WWVL).

Other known Frequency and Time Signal services:

ATA New Delhi, India (now silent)
BPM Pucheng, China 2.5, 5, 10, & 15 MHz
BSF Chung-Li, Taiwan, RoC 5, 15 MHz
DCF77 Mainflingen, Germany 77.5 kHz
EBC Cádiz, Spain 4.998 MHz
HLA Taejon, Republic of Korea 5 MHz
HBG Switzerland (now silent)
IAM Rome, Italy 5 MHz
JJY Tamura City & Saga City, Japan 40, 60 kHz
LOL Buenos Aires, Argentina 5, 10, & 15 MHz
MIKES Espoo, Finland 25 MHz
MSF Anthorn, UK 60 kHz
OMA Prague, Czech Republic 2.5 MHz (now silent)
PPE Rio de Janeiro, Brazil 10 MHz
RWM Moscow, Russia 4.996, 9.996, 14.996 MHz
YVTO Caracas, Venezuela 5 MHz

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Shortwave Radiogram now switches to MFSK64 ...

 

RSID: <<2026-07-30T23:38Z MFSK-64 @ 9265000+1500>>

This is Shortwave Radiogram in MFSK64

Please send your reception report to radiogram@verizon.net
 

The history of CHU

The broadcast of time signals in Canada began in the early 20th
Century. In 1907, station VCS in Halifax, Nova Scotia began
The first time signal broadcasts. In 1914 a survey crew at the
Quinze Dam on the Ottawa River tried to use signals transmitted
from Canadian Forces Base Kingston Ontario to calibrate equipment.
Unfortunately the signal from did not work out so they used a signal
from U. S. Navy station NAA operated in Arlington, Virginia.

In 1923 the experimental station 9CC began time signal broadcasts
on 275 metes/ 1090 khz of time signals from the Dominion Observatory
in Ottawa. In 1938, this station would become CHU after several call
sign and frequency changes.

CHU initially broadcast at a power of 10 watts on three frequencies,
3300, 7355, and 14670 khz sending a coded time signal and Morse
Code to send its ID once per hour. As coverage was spotty across all
off Canada CHU, upgraded to 300 watt transmitters.

The 1950s saw even further changes as the transmitter on 14670 khz was
upgraded to 3 kilowatts and English only voice announcements recorded
on motion picture film played back under clock control. were added.

In 1967 CHU began using cesium atomic clocks greatly improving the
accuracy of the time standard. The voice announcements were moved
to a more reliable speaking clock system in 1960. Harry Mannis of the
CBC was the English language announcer. French announcements were
added in 1964 and were recorded by Miville Couture of CBC Montreal.

Operation of CHU was transferred to the National Research Council
from the Dominion Observatory in1970. Eventually all the transmitters
and the antenna farm were upgraded to provide better service, with
3330 and 14670 both running at 3 kilowatts and 7355 running at 5 kilowatts.

Until 1990, the time on CHU was announced as Eastern Standard Time. That
year saw not only a change to using UTC, but to digital for the spoken time
and ID speech. While it was still the voice of Harry Mannis for English ones,
Simon Durivage of Radio-Canada now provided the French versions.

In 2009, CHU moved from 7355 to 7835 under spectrum re-allocations by the ITU.
Nonetheless, reception across all of Canada proved to be difficult. For consumers
in western Canada and the Arctic, CHU’s signal was unusable. In 2026, the National
Research Council ended all shortwave broadcasts from CHU, ending over a century
of keeping Canada on time. For many in North America, CHU was among the first
shortwave broadcasts they received and QSLed.

Coming up … historic QSLs from WWV and WWVH

First, The sound of WWV in the late 1960s.......

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WWV QSL Cards
 

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QSL from WWV before the move from Greenbelt Maryland to Ft Collins Colorado
February1966

Image: WWV_Maryland_February_1966
Sending Pic:215x132C;



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QSL from WWV issued on the first day of operation from Ft Collins in 1966

Image: WWV_Ft_Collins_1966
Sending Pic:216x142C;



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WWV's current QSL

Image: WWV_Present_Day
Sending Pic:217x139C;



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Next up, QSLs from WWVH.
 

But first the sound of WWV today....

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WWVH QSL Cards
 

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QSL from WWVH for the first day of operation from Kauai
July 1971
February1966

Image: WWVH_Kauai_July_1971
Sending Pic:218x140C;



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WWVH's current QSL

Image: WWVH_Present_Day
Sending Pic:219x141C;




Some rare QSL cards from WWVB and WWVL
 

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WWVL: 20 kHz. Discontinued in July 1972

Image: WWVL
Sending Pic:221x140C;

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WWVB: 60 kHz

Image: WWVB
Sending Pic:222x144C;
 

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Next up, QSLs from CHU
 

But first the sound of WWVH today....

CHU QSL Cards
 

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QSL from CHU when operated by Dominion Observatory in Ottawa

Image: CHU_Dominion_Observatory
Sending Pic:223x140C;



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The last QSL issued by CHU

Image: CHU_Last_Card
Sending Pic:225x156C;
 

Shortwave Radiogram now returns to MFSK32.....
 

But first....the last several seconds of CHU......

RSID: <<2026-07-30T23:58Z MFSK-32 @ 9265000+1500>>

This is Shortwave Radiogram in MFSK32 ...

Transmission of Shortwave Radiogram is provided by:
WRMI, Radio Miami International, http://wrmi.net
&
WINB Shortwave, http://winb.com

Please send reception reports to radiogram@verizon.net
And visit http://swradiogram.net
http://swradiogram.bsky.social
X/Twitter (for now): @SWRadiogram

This is Tony Pavick in Hope, British Columbia,
Canada and Al Holt in Alachua, Florida, USA
Please join us for the next Shortwave Radiogram.

 

RSID: <<2026-07-31T11:31Z MFSK-64 @ 15770000+1500>>

♫
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Adam Duritz of Counting Crows was born on August 1, 1964. 🇺🇸

Sending Pic:182x240;
 

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https://en.wikipedia.org/wiki/Adam_Duritz

Please report your decode to themightykbc@gmail.com and
tune in this week’s Shortwave Radiogram.

".....the {WRMI} Optimod phase rotator and filters   shift the timing of the some {AF} frequencies more than others."

Yes, that is technically possible—but the statement needs some context. It likely refers to the group delay caused by the Optimod processor in WRMI.
A phase rotator and the subsequent audio filters can indeed shift the timing of different audio frequencies by varying amounts.
 

Why?
An ideal delay element would delay all frequencies by the same amount:

 1 kHz ---> +10 ms
 5 kHz ---> +10 ms
10 kHz ---> +10 ms

The waveform remains identical in terms of timing.
However, a real audio processor does not do this.

It contains:
- High-pass filters
- Low-pass filters
- Equalizers
- Phase rotators
- Multiband compressors
- Clippers/limiters
- Stereo enhancers (if active)

These have a frequency-dependent group delay:
 

Frequency Delay
 50 Hz 20 ms
200 Hz 12 ms
  1 kHz 5 ms
  5 kHz 2 ms
 10 kHz 8 ms

The individual frequency components of a signal therefore emerge at different times.

What does a phase rotator do?
A phase rotator (frequently used in Optimod) alters the phase of low frequencies without significantly changing the frequency response.
Goal:
- more balanced audio peaks
- improved limiter performance
- higher modulation density
- less distortion

It is particularly common in AM/SW broadcasting.

However, it can alter the temporal relationship between bass, midrange, and treble.

Audible effect?

For speech:
- usually barely perceptible
- no “echoes”
- no audible delay

For certain signals:
- music with transients
- drums
- digital test signals
- MFSK/RTTY/DRM-type signals
it can be measured.


Typical order of magnitude:
- a few milliseconds
- with an unfavorable filter combination, even >10 ms

Reference to WRMI
WRMI uses or used Optimod processors (e.g., Orban Optimod-FM/AM-like processing) upstream of its shortwave transmitters.
In shortwave, the following factors also come into play:
- Receiver AGC
- Selective filter
- SSB/AM demodulator
- Audio post-filter in the SDR

As a result, a listener may sometimes get the impression:
“The high frequencies arrive later than the bass”
or
“The audio sounds like a short reverberation”

This can indeed result from a combination of Optimod group delay and receiver filtering.
But: “Optimod shifts some AF frequencies more than others”
The more precise technical formulation would be:
Yes. The Optimod phase rotator and its audio filters introduce frequency-dependent group delay, so different AF components may experience different amounts of phase shift and timing displacement.
So: Yes, the effect exists—but it’s usually small and more measurable than clearly audible.