Category Archives: What’s On Shortwave

Using synchronous detection and notch filter to eliminate het noise

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WinRadioExcalibur-VOG-Notch

The lighter shaded side of the AM carrier indicates a lower sideband sync lock. (Click to enlarge)

A few days ago, I tuned to 9,420 kHz and found a relatively strong signal from the Avlis transmitter site of the Voice of Greece. The broadcast was quite clear until a heterodyne (het) tone popped up out of nowhere.

I checked the spectrum display of my Excalibur to find two steady carriers located about .5 kHz off each side of VOG’s AM carrier. I assume this may have been a faint digital signal centered on the same frequency as VOG.

The noise was annoying, but SDRs (and many tabletop radios) have tools to help mitigate this type of noise.

The het tone was originating from both sidebands of the VOG AM carrier (see spectrum display above). I had planned to use my notch filter to eliminate the noise, but I had two carriers to notch out and only one notch filter.

VOG AM carrier

Synchronous detection to the rescue… 

The simple solution was to eliminate one of the carriers using my SDR’s synchronous detector which can lock to either the upper or lower sideband. In this case, it didn’t make any difference which sideband I locked to because both had similar audio fidelity and were otherwise noise free. In the end, I locked to the lower sideband, thus eliminating the het in the upper sideband.

Next, I enabled my notch filter and moved its frequency to cover the annoying het carrier in the lower sideband; I kept the notch filter width as narrow as I could to preserve VOG’s audio fidelity. You can see the notch filter location and width in the spectrum display above (the notch filter is the thin yellow line).

I should note here that the great thing about using an SDR–or tabletop receiver with a spectrum display–is that you can see where the noise is. I was using my WinRadio Excalibur, but pretty much any SDR in my shack could have handled this task.

The results? No het tone and I was able to preserve the great audio fidelity from the Voice of Greece broadcast!

Here’s a 3.5 hour recording I made after cleaning up the signal. I believe at one point in the recording, I switched off the notch filter to demonstrate how loud the het tone was:

Jim’s shortwave listening post is a Navy ship

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USNS Button - 02

USNS Sgt William R Button (Photo: NavySite.de)

SWLing Post contributor, Jim Clary (ND9M/VQ9JC) contacted me in June to obtain details about the BBC’s Midwinter broadcast to the British Antarctic Survey Team. Jim has been working on board the USNS Sgt William R Button since mid-June. While on board Jim has no web access, but he can send and receive emails and some files. I kept Jim informed about the time and frequencies of the BAS broadcast.

Jim had hoped to make a recording of the Midwinter broadcast at sea, but timing and some technical problems got in the way and he missed the bulk of the 30 minute program.

That’s okay, though, because Jim is an avid SWL and ham radio operator. During time off, he has logged a number of stations, so I asked if he would consider making a recording for us.  I mean, SWLing from a Navy ship?!  How cool is that?!

Within a week, Jim sent me a recording of the Voice of Korea. Here are some of his notes:

I’d heard [the Voice of Korea] many times before when Stateside (and they were Radio Pyongyang at the time), but their signals were always weak and had major polar flutter. Out here, the signal was in-my-face loud, so even though the station is not much of a rare DX catch, I wanted to get them on tape.[…]

[M]y location is the east southern Atlantic Ocean, not far from St. Helena.

[…]My ship is named USNS Sgt William R Button. The ship has been active since the mid 80s and was a “motor vessel” (M/V) until we became a Navy asset in 2009.

USNS Button - 04

[…]My receiver that I’m currently using is my QRP rig, a Yaesu FT-817ND. I changed over to a Navy antenna that I’m feeding with about 70 feet of 75-ohm RG-6 cable. There’s obviously some signal loss from both the length and impedance mismatch of the coax, but at these freqs it’s fairly negligible.

The antenna itself is an AS-2815/SSR-1 that’s mounted above the wheelhouse (bridge) of the ship. I can’t really describe the make up of the antenna simply because I don’t see why it works so well but it really does a good job. If I’d figured out where its feed point is a couple weeks ago, I would’ve had no problem logging the BBC’s Antarctic service!

.Click here to download Jim’s recording of the Voice of Korea or simply listen via the embedded player below. This broadcast was recorded on July 1, 2015 at 1900 UTC on 11910 kHz:

Many thanks, Jim! We look forward to any other recordings you wish to share!

In Pacific Islands, newspapers are a “luxury item”, radio remains the “staple medium”

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Vanuatu-MapMany thanks to SWLing Post contributor, Richard Cuff, who shares the following article from The Saturday Paper. The article speaks to how important radio
is to Pacific Islanders, and the challenges Radio Australia faces with its budget:

“For many Pacific islanders, newspapers are a luxury item. On average, each newspaper in the Pacific will be read by seven people, which helps explain why the daily paper’s print run is so low. While mobile phones are ubiquitous – top-up booths can be found in the most remote areas of the Pacific – the cost and patchy coverage of internet and TV mean radio is still the most accessible form of media.

“…?radio remains the main staple medium for the Pacific,” says Suva-born Francis Herman, who has worked in the Pacific media industry for more than 30 years as journalist, broadcaster and pre-coup CEO of the Fiji Broadcasting Corporation. “Radio stations across the Pacific are actually opening up.”

I’m speaking to Herman from a conference phone in the Pacific Media Assistance Scheme (PACMAS) office at Port Vila, where Herman works as program manager. PACMAS, a four-person team funded by the Department of Foreign Affairs and Trade (DFAT) and supported by ABC International Development, works with local and Australian media to deliver 74 programs in media training and development throughout the 22 Pacific islands.

[…]The Australian government’s lack of regard for the development of international media was made clear last year by the cancellation of a 10-year $220 million contract to deliver the international broadcasting service, Australia Network, to the Asia-Pacific region. The most worrying effect of this cut for many was the ABC’s decision to compensate for their losses by ravaging Radio Australia.

After axing three correspondents and Pacific-focused programs, Radio Australia content was replaced by translated domestic ABC programming, restricting the interaction of Radio Australia in the region and the news Australians were getting back from it.

“If the story doesn’t fit the paradigm of paradise (swaying palm trees, blue water, sandy beaches) or paradise lost (coups, corruption, climate change), voices from the islands rarely get a run,” wrote past Radio Australia correspondent Nic Maclellan for Inside Story shortly after the cuts were announced.

Shallow international content doesn’t bode well for the development of Pacific media, with a 2013 PACMAS study showing that while Ni-Vanuatu journalists self-censor to avoid retaliation from the government, they will still run investigative pieces from other news outlets.[…]”

Click here to read the full article on The Saturday Paper website…

Radio Nacional Arcángel San Gabriel returning to air July 27, 2015

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QSL received by Christoph Ratzer

QSLs received by Christoph Ratzer

Many thanks to SWLing Post contributor, Cristoph Ratzer, who shares this exciting news via the DXLD; Manuel Méndez notes:

ANTARCTICA, 15476, LRA36, Rado Nacional Arcángel San Gabriel, Base Esperanza. After months of [silence], LRA 36 will return to the air the 27th of July.
This is the mail I received from the station with this news:

“Estimado Manuel buen día, en este momento estamos en un periodo de receso hasta el día 27 de julio que comenzaremos la transmisión normal como la veníamos llevando.
Atte: Sergio LUCERO „

Thanks for passing this along, Christoph! My goal this year is to verify Base Esperanza on 15,476 kHz!

RadioNacionalArcángelSanGabrielI’ve been fascinated with this station ever since listening to Christian’s recording last year.

Check out Christoph’s QSL cards from LRA 36:
Ratzer-Arcangel-QSL-2 Ratzer-Arcangel-QSL-3

Ratzer-Arcangel-QSL-1

Shortwave Radio Recordings: Pacific Games, July 10, 2015

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mascotSRAA contributor, Richard Langley, recently shared the following recording of the 2015 Pacific Games coverage of the National Broadcasting Corporation on the Shortwave Radio Audio Archive. Richard notes:

Live three-hour recording of the 2015 Pacific Games coverage of the National Broadcasting Corporation, the Voice of Papua New Guinea (PNG), via a transmitter in Australia on 10 July 2015 beginning at 07:01:21 UTC on a frequency of 12025 kHz. At the time of the uploading of this sound file, it is not clear if the signal originated from the former Australian Broadcasting Corporation’s lower-power facility at Brandon (as registered with the High Frequency Co-ordination Conference (HFCC) organization; 25 kW beamed 80°) or their higher-power Shepparton site with 100 kW transmitters.

The recording, mostly in English with some Tok Pisin, includes commentary on the games being held in Port Moresby, music, news bulletins, public service announcements, and the NBC’s drum, flute and bird call interval signal near the top of some of the hours. Note that PNG time is 10 hours ahead of UTC.

The broadcast was received on a Tecsun PL-880 receiver with its built-in telescopic whip antenna in Hanwell (just outside Fredericton), New Brunswick, Canada. Signal quality is generally good and gets better towards the end of the recording as propagation conditions improved.

Many thanks, Richard!

Click here to download the recording as an MP3, or simply listen via the embedded player below:

Please subscribe to the SRAA podcast to receive future shortwave recordings automatically.

BBC World Service as a lifeline and making radio as “a symbol of resistance”

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BurundiMany thanks toSWLing Post contributor,  Richard Cuff, for sharing this article from the NewStatesman:

In the week when Apple’s Beats 1 radio station was launched – “Worldwide. Always on . . . It broadcasts 24/7 to over 100 countries from our studios in Los Angeles, New York and London” – there was also discussion of the BBC’s latest global audience measurement figures. The most striking thing in the report, which tracked listening habits and how they had changed over the past year, was how short-wave radio – in rural and poorer areas where there is no FM, no cable and no electricity, it’s still the only way of tuning in – is under increasing threat from something as basic as jamming.

Apple’s idea of radio as digital and impermeable never felt more breezily First World. Listeners to the English-language programmes on the BBC World Service, for example – in India, Nepal and Bangladesh, in particular – have almost halved in number because of deliberate disruption on the short-wave signal, apparently from China, forcing stations to rotate frequencies on the same band to at least attempt a slot.

“Tune around . . . You’ll find us. We will be there,” advised a technician on Over to You (4 July, 5.50pm). It conjured that most antiquated and urgent of images: a person clutching their temples, coaxing a dial, trying and trying to find a signal.

“I grew up with short-wave radio,” insisted a caller to the show, “and I got to understand the world, got to understand life. If you don’t know short-wave radio, you don’t know life.” Only moments later, there was talk of the closure of all the non-state-run radio stations in Burundi (one of the poorest and least connected countries in the world). Before the recent coup attempt, independent radio stations played a huge role in holding the government to account but many radio journalists are now forced to report using what social media is available.

“The exercise of making radio matters,” said a caller. “It’s a symbol of resistance.” And another, with some disdain, said: “Doing it on the internet is just a way of keeping it on record.” The more than century-long act of turning a dial and finding a signal, with a human voice hitching a ride on electromagnetic energy through space, is something it seems our species now feels in the bones. But worldwide? Always on? Only for some.

Read the full article at the NewStatesman.

Night of Nights XVI: July 12, 2015

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Photo: US Coast Guard

Photo: US Coast Guard

SWLing Post contributor, Brian D. Smith, writes:

“Thought I’d forward you this information on the annual “Night of Nights” event on July 12 (U.S. local time)/July 13 UTC, which provides an opportunity for shortwave QSLs – assuming the listener understands Morse code!

I’m sure you’re familiar with this one-night-a-year happening, in which maritime radio stations rise from the dead and transmit Morse code messages again for a few hours.

As a guy who honed his CW sending skills by listening to these stations’ constantly repeating messages, I have a sense of nostalgia and gratitude toward these stations, which helped me obtain my first Novice license, WN9ICB, at the age of 15 … less than 2 months after I taped the WWV recording that I submitted.”

Many thanks for the notice and sharing your nostalgia! Brian also forwarded an announcement from the Maritime Radio Historical Society of America. The MRHS describe the event:

It’s that time of year again. Time to honor all those ops who came before us by preserving their skills, traditions and culture through on the air operations.

Why 12 July? Long time True Believers know the story. But it may be worth repeating for new arrivals and to remind everyone of the traditions we hope to keep alive.

On 12 July 1999 some very tough looking grizzled old radio pioneers had tears in their eyes as the last commercial Morse code radiogram was sent. It was the end of an era. And as the last beeps faded away into the static they witnessed the end of the career to which they had devoted their lives.

These men – and some women – had stood watch over the airwaves on shore and at sea. Theirs was mostly the business of maritime commerce. But when their ship was in peril they were called upon to send the most electrifying three letters in radio, S O S, knowing that all their fellow radio operators would press their earphones close to get every scrap of information and bring aid to their stricken ship.

Once, our coasts were dotted with great Morse code radio stations, all communicating with ships at sea. They’re all gone now… all except one, the one they called the Wireless Giant of the Pacific, located at Point Reyes.

On that sad day in 1999 another event took place. The Maritime Radio Historical Society (MRHS) was formed. We made it our life’s work to honor the men and women of wireless by restoring that wireless giant. One year and one minute later the giant’s voice once again spanned the oceas as we picked up the thread and kept the faith with our colleagues of the air.

Every year since, in an event that became known as the Night of Nights, Morse code station KPH has returned to the air, joined by KFS and the station of the MRHS, KSM.

This year our friends and colleagues at USCG station NMC have labored mightily to bring that storied call sign back to life on Morse code for the evening along with NMQ in Cambria, CA..

And station NMW in Astoria, OR will be on the air as well.

Stations WLO and KLB will join us again as hey have in years past.

This is a global and local event. Hundreds of listeners around the world will be waiting with their earphones on, waiting for the signals of the great station to once again arc over the dome of the Earth to their receivers.

You can be with us in person!

My buddy, Mike (K8RAT) also notes that this “Night of Nights” event may witness the last ever Morse communications from the US Coast Guard stations. Indeed, this is mentioned in the MHRS newsletter:

This may very well be the last time ever that USCG stations can be heard on the air using A1A (Morse) emission. As new equipment is installed the hardware and wiring for Morse has been progressively removed. And the personnel who knowledgeable in the art retire or are reassigned. So be sure to listen for these stations.

I’ll not only listen to this Night of Nights, but hope to record some of the stations as well.

The frequencies for this event are numerous! I have listed the USCG (NMC) frequencies below, but please check the MHRS newsletter for MRHS and other maritime station frequencies.

Again, Brian, thanks for the heads-up!

Happy listening, everyone!

NMC (Transmit Bolinas, Receive Pt. Reyes)

Frequency            Transmitter                         Antenna

472.0                    Nautel ND2500TT/6           173′ monopole tower
500.0                    Nautel ND2500TT/6           173′ monopole tower
6383.0                  Rockwell-Collins RT-2200  Omni-directional
8574.0                  Rockwell-Collins RT-2200  Omni-directional
17220.5                Rockwell-Collins RT-2200  Omni-directional