Category Archives: DX

Sunset DX on Gary DeBock’s Cook Islands DXpedition

Many thanks to SWLing Post contributor, Gary DeBock, who shares the following notes from his Cook Islands Ultralight DXpedition:


Sunset on the Cook Islands

Aitutaki Sunset DX

Aitutaki in the Cook Islands had some dazzling sunsets, and [my wife] loved to take sunset pictures with her new phone. Of course, I participated as well. As a result, sunset DXing was pretty rare while on the trip, although 7 USA mainland stations crashed the Kiwi sunset skip DXing sessions later in the evening around 0700 UTC. None of the usual Vancouver-Seattle-Portland-San Francisco TP-DXing pest stations made it to the South Pacific, though– and I didn’t miss them a bit! 

610 KEAR San Francisco, California (5 kW at 4,610 miles/ 7,419 km) “Family Radio for the West Coast,” Christian religious format received at fair level at 0835 UTC on 4-12:

Click here to download audio.

640 KFI Los Angeles, California (50 kW at 4,570 miles/ 7,355 km) Strong (S9) level with commercial ads at 0633 UTC on 4-12:

Click here to download audio.

1070 KNX Los Angeles, California (50 kW at 4.570 miles/ 7,355 km) Powerful (S7) level with “1070 Newsradio” ID at 3 seconds, followed by national news at 0730 UTC on 4-10:

Click here to download audio.

1160 KSL Salt Lake City, Utah (50 kw at 5,144 miles/ 8,278 km) Powerful (S7) level with weather and station ID at 33 seconds, followed by public service ads at 0901 UTC on 4-12:

Click here to download audio.

1170 KFAQ Tulsa, Oklahoma (50 kW at 5,642 miles/ 9,080 km) Strong signal over apparent DU English co-channel with “Coast-to-Coast” ID at 44 seconds; thanks to Richard Allen for confirming the broadcast of the program on the station at 0845 UTC on 4-12:

Click here to download audio.

1430 KMRB San Gabriel, California (9.8 kW at 4,577 miles/ 7,366 km) Cantonese Chinese format at S7 level with commercial ads at 0830 UTC on 4-12:

Click here to download audio.

1640 KDIA Vallejo, California (10 kW at 4,633 miles/ 7,456 km) “1640-KDIA” ID at 6 seconds with Christian religious format at S5 level at 0807 UTC on 4-10:

Click here to download audio.


Thank you for sharing, Gary!  Your enthusiasm for MW DX is infectious!

A full report from Gary DeBock’s Cook Islands (Aitutaki) Ultralight DXpedition

Many thanks to SWLing Post contributor, Gary DeBock, who shares the following notes from his Cook Islands Ultralight DXpedition:


“Frequent Flyer” FSL antenna – Lagoon beach DXing setup photo

Checking out transoceanic DX propagation at an exotic ocean beach site can provide the hobby thrill of a lifetime– if a DXer is lucky enough to choose the ideal time, place and gear to make the chase. All of these fell into place in an amazing way during a 5-day trip to Aitutaki Island (2600 miles due south of Hawaii) with Ultralight radio gear, resulting in the reception of MW stations in India, Bangladesh, Mongolia and Cambodia– all at over 6,800 miles.

Because of extensive QRM from Australia and New Zealand the total number of Asian stations received was limited, but it was definitely a case of quality over quantity. Phenomenal gray line propagation around sunrise shut down Japanese signals almost completely, but boosted up those from the exotic countries in east and south Asia. Korean station reception was limited to the big guns, which was also primarily true for Chinese signals. Except for the ANZ pest QRM, the conditions seemed custom-designed for a west coast DXer to go after the exotic stations which rarely– if ever– show up in BC, Washington or Oregon (even though the Cook Islands’ distance to them is greater).

7.5 inch loopstick C.Crane Skywave SSB Ultralight

Ocean beach propagation at sunrise was strong enough to bring in both 693-Bangladesh and 1431-Mongolia at S9 levels almost every morning on my Ultralight gear, and allow both 657-AIR and 918-Cambodia to break through ANZ QRM on April 12th. No doubt many more of these exotic stations could have been logged except for Australian QRM on 576, 594, 872, 883 and 1566, but this only added to the thrill of the chase. The overall results were exceptional for a DXer using only a 7.5 inch loopstick Ultralight radio and 5 inch “Frequent Flyer” FSL– all designed to fit within hand-carry luggage, and easily pass through airport security inspections. Thanks very much to Alokesh Gupta, Hiroyuki Okamura, Jari Lehtinen, Chuck Hutton and Bruce Portzer, who all assisted in the identification of these stations!

657 All India Radio Kolkata, India, 200 kW (8,075 miles/ 12,995 km) Recorded by accident during a sunrise check of the Korean big guns at 1641 on April 12, reception of this longest-distance station went unnoticed until file review after return to the States. The female speaker (in the Bengali language) is the third station in the recording, after the female vocal music from Pyongyang BS and the Irish-accented male preacher from NZ’s Star network. Her speech peaks around 40 to 50 seconds into the recording. The isolation of the Star network at the 55 second point was done by the Ultralight’s loopstick, not by the propagation. Thanks to Alokesh Gupta for the language and station identification:

Click here to download an MP3 of this recording.

657 Pyongyang BS Pyongyang, N. Korea, 1500 kW Like most east Asian signals the N.K. big gun sounded pretty anemic in the Cook Islands. Its female vocal music at 1641 on April 12th shared the frequency with NZ’s Star network (Irish-accented preacher) and AIR’s female Bengali speaker:

Click here to download an MP3 of this recording.

693 Bangladesh Betar Dhaka, Bangladesh, 1000 kW (7,960 miles/ 12,810 km) Probably the biggest surprise of the DXpedition, with S9 signal peaks on 4 out of 5 sunrise sessions. Frequently snarling with the Oz pest 3AW, it usually managed a few minutes on top of the frequency each morning from 1630-1700 UTC. Exotic South Asian music was the usual format, and was very easy to distinguish from the talk-oriented format of 3AW (and other Oz co-channels). This first appearance at 1652 on 4-10 featured a “Bangladesh Betar” ID by a male speaker at 8 seconds into the recording (thanks to Chuck Hutton for listening):

Click here to download an MP3 of this recording.

This was followed by a lot of exotic music until 3AW claimed the frequency just before the 1700 TOH:

Click here to download an MP3 of this recording.

The next day (4-11) the exotic station was back with S9 peaks, including this typical music and female speaker at 1625:

Click here to download an MP3 of this recording.

The exotic music from Bangladesh was in an S9 snarl with 3AW (and another Oz pest) from 1659 throughout the 1700 TOH on April 11th:

Click here to download an MP3 of this recording.

774 JOUB Akita, Japan, 500 kW Oddly enough, this was the only Japanese signal making it to the island during the entire trip. Mixing with a goofy-sounding 3LO announcer at 1613 on 4-11, the Japanese female speech concerns a “doobutsuen” (a “zoo” in Japanese, similar to what the frequency sounded like with the 3LO announcer):

Click here to download an MP3 of this recording.

819 KCBS Pyongyang, N. Korea, 500 kW The N.K. big gun managed a potent signal for its 3+1 pips across its “TOH” at 1630 on 4-12 but never could shake off RNZ’s Tauranga transmitter:

Click here to download an MP3 of this recording.

909 CNR6 Quanzhou, China, 300 kW Strong signal with CNR ID (1:08) and Mandarin speech by male and female announcers. NZ’s Star network was apparently off the air at the time, since it was a real blaster when transmitting:

Click here to download an MP3 of this recording.

918 RNK Phnom Penh, Cambodia, 600 kW (6823 miles/ 10,981 km) Breaking through the Shandong and Oz QRM at an ideal time to dominate the frequency, its sign off transmission with the National Anthem peaked just before the 1700 TOH on April 12. Female speech in the Khmer language and exotic music are featured just before the anthem (thanks to Hiroyuki Okamura and Jari Lehtinen for listening, and identifying the National Anthem):

Click here to download an MP3 of this recording.

Chuck Hutton’s improved audio file of the same reception (thanks):

Click here to download an MP3 of this recording.

918 Shandong RGD Synchros (Multiple) The dominant Asian signal on the frequency, it rarely allowed Cambodia to sneak through. Here it is with female Mandarin speech at 1647 on 4-11:

Click here to download an MP3 of this recording.

Shandong RGD’s transmitters were poorly synchronized, resulting in the two-tone time pips at the 1700 TOH on 4-12 (during Cambodia’s National Anthem at 1:40, in the MP3 linked below). Although actually from two different transmitters, the sound effect sounds similar to that of a “cuckoo clock,” resulting in some initial confusion about their source:

Click here to download an MP3 of this recording.

972 HLCA Dangjin, S. Korea, 1500 kW The South Korean big gun played the part on most mornings, including this S9+ Korean female speech at 1631 on 4-12:

Click here to download an MP3 of this recording.

981 CNR1 Synchros Changchun/ Nanchang, China, 200 kW/ 200 kW The first of three CNR1 frequencies which usually produced strong signals, this music // 1377 was received at 1624 on 4-12:

Click here to download an MP3 of this recording.

1377 CNR1 Synchros (Various) Overall this was not only the strongest Chinese frequency on the band, but was the strongest Asian station on the band as well. Awesome S9+ signals were typical each morning, as with this male speech and music at 1622 on 4-12:

Click here to download an MP3 of this recording.

Another potent signal from this Chinese blaster at 1640 on 4-12:

Click here to download an MP3 of this recording.

1431 Mongolia (Relay Station) Choibalsan, Mongolia, 500 kW This station was easy to receive on the first attempt, with very little competition on the frequency. It typically managed an S9 signal after 1630 daily with the BBC’s Korean service, which seemed to be broadcast during the peak sunrise enhancement time in Aitutaki’s ocean-boosted propagation. Here is BBC’s Korean male announcer at an S9 level at 1632 on 4-11, with the BBC interval signal at 47 seconds into the recording:

Click here to download an MP3 of this recording.

The Mongolian relay program prior to 1630 was also in Korean, with this female Korean speech at 1627 on 4-11:

Click here to download an MP3 of this recording.

1566 HLAZ Jeju, S. Korea, 250 kW A very poor signal was typical during this trip, with the Chinese service barely showing up under 3NE and two other DU English stations (probably 4GM and Norfolk Island). Whenever 3NE was in a fade it had a chance, since other two co-channels were running very low power. Here is the latter situation, with the weak Chinese barely audible under the DU English snarl at 1641 on 4-12:

Click here to download an MP3 of this recording.

1593 CNR1 Changzhou, China, 600 kW This was another Chinese blaster, with S9 signals typical every morning. Here it was at 1641 on 4-12 with male Chinese speech and music at 1377:

Click here to download an MP3 of this recording.

73 and Good DX,

Gary DeBock (DXing in Aitutaki, Cook Islands)


Amazing, Gary! Thank you for taking us along on your excellent Ultralight DXpedition. With a modest portable radio and a little antenna ingenuity, you’re enjoying some outstanding DX! You’re living proof of the point I was trying to make in a post yesterday!

Thanks again, Gary, and good DX! 

Don’t buy into the doom-and-gloom: Low sunspots are not the end of DXing!

In response to the spaceweather.com article about a lack of sunspots I posted yesterday, SWLing Post contributor, Rob Wagner (VK3BVW), replies:

Oh Thomas! Really?
It’s not all doom-and-gloom, you know! The low-frequency part of the SW spectrum is proving very good value at the moment. And the mediumwave guys are telling me that there’s plenty of DX to be had in that part of the RF spectrum.
And yesterday, I had some FT8 success!
From southeastern Australia on a dipole with 5w getting into Plymouth, Minnesota on 14mHz in the mid-afternoon here. Not bad at all for the bottom of the sunspot cycle!

Ha ha! Thanks for your reply, Rob! Honestly, I wasn’t trying to spread doom-and-gloom, rather I was pointing out how low this sunspot cycle has gone. (Okay, so perhaps I was also shaking my fist at our local star!)

I completely agree with you Rob. It’s not all doom-and-gloom! Here are a few strategies for working DX during sunspot lows:

Go low!

Sunspots really enhance propagation on the higher HF bands:  especially 17 meters and higher. Without supspots, you’re not going to reliably snag serious DX on 10 meters, for example–there will be the occasional opening, but it might not last long. During sunspot cycle peaks, the higher bands provide outstanding DX opportunities even with a modest setup.

During one peak, I’ll never forget sitting in my car in North Carolina, with a RadioShack 10 meter mobile radio connected to a mag mount antenna, and having a three way chat with a ham in Sandiego, CA and one in Glasgow, Scotland.

With that said, even this year I’ve snagged some excellent DX on 17 meters (my favorite HF band). And, as you point out Rob, 20 meters is a great band for snagging serious DX even with no sunspots giving you a boost.

Openings between the US and Australia happen routinely on the 40 meter band as well, although some of us might have to wake up early or go to bed late to participate.

Of course all of this same advice applies for SWLing. Most of the DX I snag these days is found on the 25 meter band and lower. I’ve also been using this opportunity to explore Mediumwave DXing.

Digital Modes

Kim Elliott and I had an exchange about this yesterday on Twitter. Some digital modes are so robust they seem to work regardless of propagation.

Kim knows this well as he receives reception reports from Shortwave Radiogram listeners across the globe each week.

If you’re a ham radio operator, I strongly encourage you to check out the latest “weak signal” digital modes: JT65 and, especially, FT8.

In fact, SWLing Post contributor, Robert Gulley (AK3Q), wrote an excellent introduction to these modes in the June 2017 issue of The Spectrum Monitor magazine.

Robert and I talk about the FT8 mode frequently. Since I discovered this mode at the 2017 W4DXCC conference, I’ve been hooked. Sure–it lacks the nuances of phone and CW, but it’s incredibly fun to watch my flea-powered signal acknowledged by someone on the other side of the planet with a flea-powered signal.

As Robert will tell you, FT8 seems to defy propagation theory. I agree wholeheartedly.

I’ve worked some of my best DX with this mode during the sunspot low and have never used more than 15 watts out of my Elecraft KX3 and KX2.

Don’t give up!

Although propagation was poor, I worked more stations during National Parks On The Air than I had worked the entire time I’ve been a ham radio operator. All in the field with modest portable antennas and 15 watts or less.

Use the sunspot low as an excuse to explore frequencies and modes you’ve never used before. Use this as an opportunity to improve your listening skills and the most important part of your listening post or ham station–your antenna system!

I regularly get email from people who’ve found the SWLing Post and take the time to write a message to me complaining about the death of shortwave radio: the lack of broadcasters, the prevalence of radio interference and the crummy propagation.

My reply?

“Hey…sounds like radio’s not your thing!”

While this same person is moaning and complaining, I’ll be on the radio logging South American, Asian and African broadcast stations.

I’ll be working DX with QRP power, even though everyone tells me that’s not possible right now.

I’ll be improving my skill set and trying new aspects of our vast radio world.

You see: I’ve learned that the complainers aren’t actually on the air. They gave up many moons ago because someone told them it wasn’t worth it, or they simply lost interest. That’s okay…but why waste time complaining? Go find something else that lights your fire!

While these folks are complaining, I’ll be on the air doing all of the things they tell me I can’t do.

Rob, thanks for your comment!

Results: AirSpy HF+ vs Elad FDM-S2 Weak Signal Comparisions

Looking north toward Cape Lookout, Oregon, near the site of my SDR receiver recordings. Photo courtesy of Wikimedia Commons.
In my original article 10 days ago, I set up a SWLing Post reader poll to let you give your opinion on which shortwave recordings within four pairs of audio files provided the most intelligible result. The recordings were intentionally noisy, low-level signals to help us discover–through critical listening to the files–if there is a clear favorite between the AirSpy HF+ or the Elad FDM-S2 receivers. Of course, there were only four pairs of recordings…not a very large sample size.

However, 34 readers of the original article took the time to listen and respond, so let’s get to the numbers, shown in these graphs:

Interestingly, the responses above seem to point to:

  • Two recording pairs tied in the results (50% / 50%) or were very close (HF+ 52.9% / FDM-S2 47.1%)
  • The FDM-S2 led one recording pair by a large margin (67.6% / 32.4%)
  • The HF+ led another recording pair by an equally large margin (67.6% / 32.4%)

Taken as a whole, no obvious winner emerged, although one might conclude the HF+ has a slight edge due to its lead in the “very close” recording pair of 7.230 MHz.

One thing is clear–the AirSpy HF+ is a surprisingly good performer for its price of $199 USD! For many enthusiasts this will be all the SDR they need.

As a final note, I’ll mention that the AirSpy HF+ used for the tests was totally stock. I have not yet performed the “R3 Bypass” mod nor the firmware update to my HF+ units. The simple R3 Bypass, discussed at length on the AirSpy Groups.io forum, significantly boosts sensitivity of the HF+ from longwave up to about 15 MHz, without any noted overload issues. For more on this modification from a MW DXer’s perspective, read Bjarne Mjelde’s insightful article at his Arctic DX Blog.

Thank you to all the readers who took the time to listen to the SDR recordings in this comparision and register your opinions.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

Digging in the Noise: Weak Signal Audio Recovery with the AirSpy HF+ and Elad FDM-S2

I’m currently spending the better part of a week at Cape Lookout State Park on the Oregon coast, with a great view of the ocean through tall evergreen trees. This is one of my favorite parks in the Pacific Northwest, especially when DXing during the blustery winters from one of the nice cabins at Cape Lookout.

The view from the beach near my cabin; the turbulent waves were a precursor to the gale force winds at the park during the night of the 23rd!

Although I’m at the park for trans-Pacific medium wave DXing, I’m also comparing receivers, both SDRs and portables. This morning I sought out a few weak shortwave signals, pitting the Elad FDM-S2 SDR ($529 USD) against the AirSpy HF+ ($199 USD). I have a pair of the HF+ receivers to cover all of medium wave (as the FDM-S2 easily does). Many SWLing Post readers already know that the upstart HF+ trades bandwidth to gain high performance in order to keep the price reasonable.

My antenna used for the following recordings was a small “Flag” antenna using a Wellbrook Communications FLG100LN module and a 2K ohm variable potentiometer for termination. The design uses crossed tent poles in an “X” formation to support the wire loop. This design travels easily in a compact package; I have Dave Aichelman of Grants Pass, Oregon to thank for this very useful “tent pole loop” implementation of the Wellbrook FLG100LN.

The Wellbrook-based antenna functions superbly, and its low-noise design helps hold down QRM from the nearby cabins (which unfortunately have been “upgraded” recently with noisy cold fluorescent [CFL] light bulbs). The area around the Cape Lookout cabins used to be superbly low noise and suitable for radio listening, but now it is more of a challenge than before. The Wellbrook FLG100LN is perfect for the situation though; Wellbrook ALA1530LN  Pro and ALA1530S+ 1-meter loop antennas work commendably at the park too.

The Wellbrook FLG100LN module with a home brew RFI choke in-line

A 2K ohm variable potentiometer is protected from the elements in a small plastic bag. The “pot” is adjusted for the best nulling of medium wave stations off the back side of the antenna’s reception pattern.

The “tent pole loop” antenna is strapped to a fence railing with ultra-strong Gorilla Tape to keep the 7-ft. square loop vertical.

On with the recordings…

For the FDM-S2 and HF+ comparisons I used the SDR-Console V3 software. Every parameter was identical for the receivers–sampling bandwidth, filter bandwidth, AGC, mode and so on.

Take a critical listen to the weak signals recorded with the SDR receivers, identified as only “Radio A” and “Radio B”. A link to a poll is at the end of this article; please indicate which recording of each pair has the most intelligible audio in your opinion, and submit your choices when you’ve made up your mind on each audio clip. After a week or so I’ll post the results of the voting, and identify the receivers.

9.615 MHz, LSB, Radio A


9.615 MHz, LSB, 
Radio B (note: the same male announcer heard in clip “A” begins at 00:14 in this “B” clip)

 

9.730 MHz, USB, Radio A


9.730 MHz, USB, 
Radio B

 

7.230 MHz, S-AM, Radio A


7.230 MHz, S-AM, 
Radio B

 

9.860 MHz, S-AM, Radio A


9.860 MHz, S-AM, 
Radio  B

 

Note on 7.230 MHz recording: this was an interesting frequency, as the signal was tightly surrounded by a very strong local 40m ham radio LSB station as well as a strong China Radio International signal. There were other strong amateur and broadcast stations within 30-50 kHz of 7.230 MHz, also. This A-B test more than the others may indicate receiver performance in a strong RF environment on a crowded band.

Ready for the poll? Register your votes at the Google Docs form below:

https://tinyurl.com/ya38wj69

In a week to 10 days I’ll post the results in another article. NOTE: I haven’t provided a “both sound the same” choice in the poll to encourage you to ‘dig deep’ into the audio and listen critically–to find something that stands out in one clip versus the other.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.