Tag Archives: Time Stations

Using Doppler Shift and Time Stations to Detect Solar Flares

A WWV Time Code Generator (photo taken at WWV in Fort Collins, Colorado)

Many thanks to SWLing Post contributors, Troy Riedel and Jock Elliott, for sharing the following post from Spaceweather.com:

A NEW WAY TO DETECT SOLAR FLARES: Around the world, ham radio operators are experimenting with a new way to detect solar flares–the Doppler Shift method. Brian Curtis of Sault Ste Marie, Michigan, demonstrated the technique on June 20th when the sun produced a powerful X1.1-class solar flare:

Image by Brian Curtis

“I monitor the frequency and field strength of Canada’s CHU time station transmitting at 7850 KHz,” explains Curtis. “During the X-class flare event, I was able to detect the Doppler shift of the station’s carrier frequency (green plot). It shifted by 5 Hz, which is a small change, but very obvious!”

When radiation from a solar flare hits Earth’s atmosphere, it ionizes the air, temporarily boosting the thickness of our planet’s ionosphere. Any radio station skipping off the ionosphere will suddenly find its frequency Doppler shifted (because its reflection point is moving). Shortwave stations such as WWVWWVH, and CHU transmit carriers with atomic-clock grade frequency stability, so they are perfect sources for Doppler monitoring.

Sudden changes in the ionosphere caused by flares or even sunrise/sunset can Doppler shift the frequency of stations like WWV. Image credit: Collins et al (2021) [Original image via HamSci and SpaceWeather.com]

“I have been monitoring radio stations for decades, noting sudden changes in signal strength as a means of monitoring space weather events,” says Curtis. “It is only fairly recently (~4 months) that I started to experiment with monitoring the Doppler shift of HF stations. The June 20th X-class flare event is by far the most dramatic that I have witnessed thus far.”

Would you like to detect solar flares this way? The HamSCI citizen science program has developed a Personal Space Weather Station specifically for Doppler shift measurements. This technique can also be used to study solar eclipsesearthquakes and tsunamis, and much more.

Click here to read the full story on Spaceweather.com, more on EOS.org and HamSCI.org

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Jock says, “It’s about time…and beacons!”

A WWV Time Code Generator

Many thanks to SWLing Post contributor, Jock Elliott, who shares the following guest post:


It’s about time . . . and beacons

By Jock Elliott, KB2GOM

Shortwave time stations can be incredibly useful for shortwave listeners, not just for checking the time, but also for finding out what’s going on with radio signal propagation. What makes these stations particularly valuable is that they are available all the time. I use them often when I am testing radio equipment or tweaks to my listening post.

Chief Engineer Matt Deutch at WWV/WWVB. (Photo: Thomas)

The National Institute of Standards and Technology (part of the U.S. Department of Commerce) maintains a couple of stations devoted to broadcasting time announcements, standard time intervals, standard frequencies, UT1 time corrections, a BCD time code, and geophysical alerts 24 hours a day, 7 days a week.

WWV in Fort Collins, Colorado, according to NIST:

“radiates 10 000 W on 5 MHz, 10 MHz, and 15 MHz; and 2500 W on 2.5 MHz and 20 MHz. Each frequency is broadcast from a separate transmitter. Although each frequency carries the same information, multiple frequencies are used because the quality of HF reception depends on many factors such as location, time of year, time of day, the frequency being used, and atmospheric and ionospheric propagation conditions. The variety of frequencies makes it likely that at least one frequency will be usable at all times.”

In addition, WWV broadcasts the same signal heard on the other WWV frequencies on 25 MHz on an experimental basis. The power is 2500 W and, as an experimental broadcast, is may be interrupted or suspended without notice.

WWVH crew from left to right: Dean Takamatsu, Dean Okayama, Director Copan, Adela Mae Ochinang and Chris Fujita. Credit: D. Okayama/NIST

WWVH, based in Kekaha, Hawaii, transmits 10000 W on 10 MHz and 15 MHz, and 5000 W on 2.5 MHz. A NIST notes that the 5 MHz broadcast, which normally radiates 10 000 W, is currently operating at 5000 W due to equipment failure.

Photo Thomas (K4SWL) took in 2014 of the sign above WWV’s primary 10 MHz transmitter.

Both stations have voice announcements. WWV uses a male voice; WWVH, a female voice. They are staggered in time so that they don’t talk over each other. While doing research for this blog, one afternoon on 5 MHz and 10 MHz, I could hear the female voice, followed by the male voice, so I was hearing both Hawaii and Colorado. On 15 MHz, I could hear only Hawaii. Both stations transmit in AM mode, although I sometimes use upper sideband to pick the signals out of the noise.

CHU’s QSL card used in the 1980s depicting Sir Sanford Fleming, father of uniform times zones.

In addition, there is a Canadian time station. CHU transmits 3000 W signals on 3.33 and 14.67 MHz, and a 5000 W signal on 7.85 MHz.

The frequencies were chosen to avoid interference from WWV and WWVH. The signal is AM mode, with the lower sideband suppressed.

The same information is carried on all three frequencies simultaneously including announcements every minute, alternating between English and French. The CHU transmitters are located near Barrhaven, Ontario.

According to a posting on Radio Reference, there is also a time beacon in Moscow, Russia that transmits on 9996 and 14996 kHz in CW mode. I have never heard that station.

If anyone knows of additional shortwave time stations, please post the information in the comments section below.

Beacons

Another “standard reference” that can be used to figure out what’s happening with shortwave propagation is the International Beacons Project, a worldwide network of radio propagation beacons. It consists of 18 Morse code (CW) beacons operating on five designated frequencies in the high frequency band. The project is coordinated by the Northern California DX Foundation (NCDXF) and the International Amateur Radio Union (IARU).

This page shows the locations of the beacons and gives samples of the signals that can be heard. Each beacon transmits once on each band once every three minutes, 24 hours a day. A transmission consists of the callsign of the beacon sent at 22 words per minute followed by four one-second dashes. The callsign and the first dash are sent at 100 watts. The remaining dashes are sent at 10 watts, 1 watt and 100 milliwatts. At the end of each 10 second transmission, the beacon steps to the next higher band and the next beacon in the sequence begins transmitting.

Clicking around the International Beacons Project website will reveal a wealth of information, including a Reverse Beacon Network — https://www.ncdxf.org/beacon/RBN.html — no kidding.

Finally, if you would like to disappear down the rabbit hole of chasing shortwave beacons, here is a list of 411 beacons around the world: http://www.dl8wx.de/BAKE_KW.HTM

The listing includes the frequency, the location, and the power of the transmitter (among other things). If any reader has experience with these beacons, please post in the comments section.

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Canada: National Research Council official time signal turns 80

(Photo credit: @chuttersnap)

(Source: CBC via William Lee)

In the 1930s, it helped sailors properly set their instruments for navigation.

It allowed railway companies to be punctual, and helped Canadians set their watches with precision every day.

Today, if you’re a CBC Radio aficionado, you may recognize its repeated beeps over the airwaves every day just before 1 p.m. ET.

To many, the National Research Council official time signal is a fixture of Canadian society. And on Nov. 5, the longest running segment on CBC Radio turns 80 years old.

Day 6 host Brent Bambury spoke with Laurence Wall, one of the current voices of the National Research Council time signal, about its origins, its importance, and where it stands in the digital age.[…]

Click here to read the full article and listen to the interview and audio clips.

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Leap second added to 2016

(Source: NPR)

Here’s a timely reminder for all you would-be revelers out there: Be careful with your countdowns this New Year’s Eve. There will be a little extra time to bask in the glow of a retreating 2016 — or curse its name, as the case may be.

Whatever your inclination may be, one thing is certain: Before the year is out, the world’s foremost authority on time will be adding one more second to the clock.

In a bulletin released this summer, the International Earth Rotation and Reference Systems Service, or IERS, said it would be necessary to introduce a “leap second” at the end of December. Timekeepers use this added second much as leap years are used — to bring the world’s atomic clocks in sync with the Earth’s own distinctive rhythm, which in this case is determined by its rotation.

This leap second isn’t the first. Since 1971, the world has added leap seconds with some regularity — typically every two to three years — and the latest leap second was added only last year, in June.

Continue reading at NPR…

Last year, I recorded the 2015 Leap Second via WWV–click here to read that post. Though such a subtle change, it is fun to hear that extra second added. I plan to record the full 31 meter band New Year’s Eve–hopefully, I’ll also catch the 10,000 kHz WWV Leap Second!

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The Empire Strikes Back: Is that WWV I hear?

Fullscreen capture 12202015 40448 AMWith all of the Star Wars: The Force Awakens hype going on, I remembered that, as a kid, I thought I heard WWV in a scene from The Empire Strikes Back.

I looked through some video clips of the movie online and discovered it again this morning: I heard the WWV-like sound in the Battle Of Hoth scene. [Update: RadioGeek suggests this may actually be CHU’s date pips.]

This video clip will start around the :23 second mark; start listening for the metronomic tick in the background around :25 seconds and then again at :40 seconds:

I may be mistaken, but I believe that sounds like 1980s era WWV. Has anyone else noticed this?

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Recording the 2015 Leap Second

Fullscreen capture 6302015 115321 PM

Yesterday, I posted a brief article about the leap second that occurred between 23:59:59 June 30, 2015 and 00:00:00 UTC July 01, 2015.

I decided to record the leap second on as many shortwave time station frequencies as possible. The only viable options for me–based on time of day and my reception location–were the WWV frequencies 10, 15, 20, and 25 MHz, and CHU frequencies 7,850 and 14,670 kHz.

I was able to record four different time station frequencies simultaneously on the TitanSDR Pro.

I was able to monitor four different time station frequencies simultaneously on the TitanSDR Pro. (click to enlarge)

Unfortunately, HF propagation was very poor yesterday, so the higher WWV frequencies–20 and 25 MHz–were completely inaudible, as was CHU on 14,670 kHz. There were numerous thunderstorms in our area, so static crashes were prevalent.

Still, since this was a first attempt to record a “leap second,” I didn’t want to take any chances.  I had the Titan SDR Pro monitoring and recording two CHU and two WWV frequencies [screenshot], the Elad FDM-S2 recording WWV on 15 MHz [screenshot], and the WinRadio Excalibur on WWV’s 10 MHz frequency, as well as recording the whole 31 meter band spectrum [screenshot].

In the end, the strongest frequencies I captured were CHU on 7,850 kHz and WWV on 15,000 kHz. WWV on 10,000 kHz was much weaker than normal and the band was quite noisy–still, it’s readable, so I included this recording, too. Recordings follow…

Recordings

Photo I took in 2014 of the sign above WWV's primary 10 MHz transmitter.

The sign above WWV’s primary 10 MHz transmitter (2014).

All of the recordings start just before the announcement of 23:59 UTC.

WWV added the extra second and higher tone, then continued with their top of the hour announcements, including a note about leap second (which begins after the 00:04 announcement). CHU simply injects a one second silence before the long tone.

WWV on 15,000 kHz using the Elad FDM-S2:

CHU on 7,850 kHz using the TitanSDR Pro:

WWV on 10,000 kHz using the WinRadio Excalibur:

One interesting note about the 10 MHz WWV recording above: I believe I may be hearing BPM China in the background. I’m curious if anyone can confirm this because I don’t know BPM’s cadence/pattern well enough to ID it.

Other recordings…?

Did you record a shortwave time station as leap second happened? If so, please comment, and feel free to share a link to your recording!

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Hang on a second…seriously

WWV-TimeCodeGenerator

One of four WWV time code generators in late August, 2014

Tonight, for the first time in three years, we will experience a leap second. What is a leap second?  Wikipedia provides a concise explanation:

A leap second is a one-second adjustment that is occasionally applied to Coordinated Universal Time (UTC) in order to keep its time of day close to the mean solar time, or UT1. Without such a correction, time reckoned by Earth’s rotation drifts away from atomic time because of irregularities in the Earth’s rate of rotation. Since this system of correction was implemented in 1972, 25 such leap seconds have been inserted. The most recent one happened on June 30, 2012 at 23:59:60 UTC. A leap second, the 26th, will again be inserted at the end of June 30, 2015 at 23:59:60 UTC.

Like many of you, when I think of time–or UTC–I think about the NIST radio station WWV in Fort Collins, Colorado.

I had the honor of visiting the facility last year (yes, photo tour still forthcoming!).  During the tour, my guide and Chief Engineer at WWV and WWVB, Matthew Deutch, told me that he’s always going to be on site come Leap Second!

MattDeutch-WWVB

WWV’s Matthew Deutch with WWVB antennas in background

I wrote Matt this morning to ask what were his plans tonight?  His reply:

“The leap second happens at 0000 UTC tonight, which is 6:00 pm here in Fort Collins. All of the programming took place at the beginning of the month, so the equipment is armed…we just sit back and watch for the leap this evening.

Even though it is automated I hang around the station to make sure everything goes smoothly at the critical moment…”

WWV-First-Sign-SMMatthew closed his message by wishing me a “Happy Leap Second.”

Back at you, Matt! We hope that second leaps as smoothly as you’d like!

Not to put Matt on the spot, but you can listen to WWV (or the atomic clock of your choice) make the leap second tonight at 00:00 UTC. As for me, I’ll hop on 10 MHz and 15 MHz to hear (and hopefully record) the extra “tick.” At the end of this post, I’ve provided a list of time stations for your convenience.

Happy Leap Second!

20MHZtransmitter

WWV 20 MHz Collins transmitter

List of shortwave radio time stations

  • CHU Canada: 3330 kHz, 7850 kHz, 14670 kHz
  • BPM China: 2,500, 5,000, 10,000, and 15,000 kHz
  • HLA South Korea: 5,000 kHz
  • BSF Taiwan: 5,000 and 15,000 kHz
  • WWV (Ft. Collins)/WWVH (Hawaii) United States:  2,500, 5,000, 10,000, 15,000, 20,000 and 25,000 kHz

Update

Click here to listen to Leap Second recordings from WWV and CHU.

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