Category Archives: DX

Part Three: A Beginner’s Guide to ALE

Many thanks to SWLing Post contributor Don Moore–noted author, traveler, and DXer–who shares the following post:

A Beginner’s Guide to ALE: Part Three

By Don Moore

Don’s traveling DX stories can be found in his book Tales of a Vagabond DXer [SWLing Post affiliate link]. If you’ve already read his book and enjoyed it, do Don a favor and leave a review on Amazon.

In the first two parts [Part 1 and Part 2] we looked at software used to decode ALE signals. Now let’s look at the stations and countries waiting to be logged.

If you’ve read the first two parts of this series then you know that there is no listening involved in ALE DXing. I know some traditionalists who would claim it’s not real DXing if you aren’t sitting next to the radio listening to a speaker or headphones. To me, DXing is having fun by logging new and interesting stuff. With ALE, the fun comes from researching the callsigns and frequencies to figure out what was logged. Every DX session produces numerous puzzles.

Identifying ALE stations may not sound hard. After all, one of the best things about monitoring ALE is that the stations are constantly identifying themselves. What could be easier? Unfortunately, it’s not always that easy to match up the callsign with what organization is behind it. Obvious location identifiers like ILLAPEL and VILLAVICENCIO2 are the exception, not the rule.

Around a third of the callsigns I decode stay complete mysteries as to who is behind them and where they are from. For about another third, the organization may be known (and, by extension, the country), but not the transmitter site. Only about a third of my ALE catches can be pinpointed exactly on a map as to where they came from. I wish it were more than that, but that doesn’t mean I haven’t logged some really interesting and unusual places.

Actually, it is surprising that I can pinpoint as many as I do. After all, every ALE network I’m aware of belongs to a government agency, a military, or some other government-affiliated organization. Bureaucracies like those are typically very careful about how they share information even when there is absolutely no security risk involved. Nevertheless, the utility DX community has gathered some excellent information over the years. While some of it is researched from public sources, I understand that some of it comes from inside sources that certain DXers have with people who install the networks. I don’t ask questions about where the information comes from and I’m glad to have the references and lists, which you can find in the links below.

Join the UDXF

The best source of ALE information is the Utility DXers Forum. The UDXF website has a lot of great utility resources that anyone can download. The best information, however, is the members’ loggings. To see those, you have to join the mailing list, where you can see member logs reported in the daily messages. But what you want to do is download the log compilations from the Files section (at Groups.io). Those go all the way back to the UDXF’s founding twenty years ago.

The first zip file is a compilation of all the logs from 2006 to 2019. After that, the logs are compiled into files for each year from 2020 to 2025. Download all of these and unzip them into a single folder. And periodically check back for newer files. At the beginning of each month, there will be a compilation for the previous month. Those will be compiled into a single file for 2026 at the beginning of next year. Finally, you need a way to search within the contents of an entire folder of files. A good text editor, such as Notepad++ for Windows, will do the job.

So let’s say I have a logging with the ID of 355013 on 8092 kHz. That really doesn’t tell me a thing about who could be behind the signal. Lots of organizations use six-digit strings as identifiers. I open up the Find in Files feature in Notepad++ and point it at the folder of UDXF logs. Now I type in the ID followed by a colon. Why a colon? Because in the UDXF logs, IDs are followed by a colon. By including the colon in my search term, I can eliminate any other random places that the same string of characters might be. (That’s more important when searching for shorter ID strings, such as three-digit numbers.)

I click Find All and get back a listing of every line in those logs that contains my search string. I can click on any line to open that file at that point. In the frequency column here, I see two hits for this ID on 8092 kHz. I think I can be certain that this is the Turkish Civil Defense station in Samsun province.

But what if I got these same results, but without any reports on 8092 kHz? That wouldn’t prove that I had logged Samsun even though the six-digit ID is a match on other frequencies. There are other organizations that also use six-digit numbers as IDs, such as UN Peacekeepers in several African countries. What I would do then is run a search for the frequency of 08092 (no colon) to see what other stations have been reported there. That turns out to be an important frequency in the AFAD network, so I could still safely assume that I had logged Samsun.

If the identifier doesn’t show up in the UDXF logs then there are some other resources (listed below) that can be checked. Sometimes the UDXF has complete network lists that include stations not yet reported in the logs. Another thing to do is look to see just what has been reported on that frequency. If there are lots of logs from a particular organization and the IDs follow the same pattern as the one you logged (e.g., six digits beginning with a ‘3’), then you likely got an unknown station in the same network.

If I get this far and still have no idea who is behind the station, then I have two options. I can delete the log and forget about it. Or I can put it in a ‘check later’ list, which I go through every year or so. I’ve identified a number of stations that way, especially from new networks. To be honest, which one I choose to do depends on how I feel that day!

Now let’s take a look at some of the places that stations can be logged from.

North America

The US government heavily uses ALE and there is no question that you will log more stations from the USA than from any other country.

The most widely used set of frequencies by the US government includes 7527, 8912, 10242, 11494, 12222, and 15867 kHz. These frequencies are shared by several organizations, including the US Coast Guard, the FBI, the DEA (Drug Enforcement Agency), and the Customs and Border Patrol. The USCG is an especially heavy user, and it’s easy to log not only USCG bases but also USCG cutters at sea, as well as USCG aircraft. Another heavy user of these frequencies is the COTHEN network, or Cellular Over-The-Horizon Enforcement Network. This is a network of various law enforcement agencies and includes stations in some unusual places such as Limestone, Florida, and Lovelock, Nevada. Here is a string of Black Cat loggings on five different frequencies by MEM, the COTHEN station in Senatobia, Mississippi.

Another large US government ALE network is run by FEMA (Federal Emergency Management Agency), which operates stations at each of its ten regional offices. The callsigns include the region number, e.g. FC4FEM1 from the region four office in Thomasville, Georgia. If you are in North America, it won’t take long to log all ten regions. Much rarer are the stations in individual state offices, such as SD8FEM in South Dakota and TN4FEM in Tennessee.

Some state National Guard units also operate on ALE, but by far the most active are the Wyoming and Utah National Guards. These can be logged on several frequencies, including 7805, 7932, and 8065. The Wyoming stations mostly identify by the full town name, e.g. LARAMIE or GILLETTE, while the Utah stations use the first three letters of the local base, e.g. AME for American Fork or TOO for Toole. In September, I passed through Vernal, Utah, and took these pictures of the Vernal National Guard center and the HF antennas on the roof.

Finally, there are several regional government and quasi-government organizations that can be logged. The most active network is probably the Bonneville Power Administration in the Pacific Northwest. It operates a handful of stations with calls including 1121BPA and 1351BPA. Unfortunately, there is no information as to where the individual stations are located.

US government ALE transmissions are not confined to the continental USA. As noted in part one of this series, the US Air Force operates from bases around the world. The US Coast Guard operates from Puerto Rico, Guam, Alaska, and Hawaii. The DEA has a station in Nassau, Bahamas. Finally, the US State Department operates from many consulates and embassies around the world.

The Canadian military has a few ALE stations on the air. Aside from that, to my knowledge, there is no ALE activity from Canada, Mexico, or any of the countries in Central America and the Caribbean, except for that done by the US government.

South America

The militaries of Brazil, Colombia, and Venezuela all operate ALE networks. The Brazilians seem to be particularly active. The police networks of Chile and Colombia, as mentioned in part one, are the most interesting as they identify with the station location. However, logging the Chileans in the northern hemisphere will require good conditions. I’ve only managed to get a few when DXing in the USA, although I have logged several more while DXing in South America.

Africa

Algeria is the heaviest user of ALE from Africa. The Algerian Air Force and Army operate from bases throughout this huge country, and in many cases, the exact locations of the stations are known. One of my favorite ALE logs is CM6 from Tamanrasset in the heart of the Sahara in southern Algeria. Sonatrach, the Algerian national oil company, also has a huge network of stations using four-digit numbers as identifiers. Unfortunately, there is no information as to the exact location of any of those stations.

Morocco, Mauritania, and Tunisia are three other countries with large ALE networks operated by their militaries and/or national police. Finally, United Nations Peacekeepers operate from several countries, including Mali, the Central African Republic, and South Sudan.

Europe and the Middle East

The United States may have the most ALE stations, but without a doubt, the most active ALE callsign is XSS from Forest Moor, England. Operated by the British military, this station pops up on dozens of frequencies throughout the shortwave spectrum. The previously mentioned Turkish AFAD operates what is probably the largest ALE network in this region. Another large network is Italy’s Guardia di Finanza, a sort of combination coast guard and tax enforcement agency. It’s hard to receive in North America, but I did once get one of their patrol boats. ALE is used by the militaries and border patrols of several other countries in this region. My best ALE catch from Europe is getting the Polish UN Peacekeepers in Kosovo. That’s my only logging of any type in that small country.

Asia and Pacific

Australian state police run an ALE network with 10505 kHz being a favorite frequency. To my knowledge, there is no other significant ALE activity in the region aside from that of various US government organizations.

That’s just a general overview of the major users of ALE, but there is a lot more to be logged that I didn’t mention. Unlike a lot of things on HF, the use of ALE is expanding, not contracting. For example, the Colombian police network didn’t even exist two years ago. So, give ALE monitoring a shot. I think you’ll find it to be one more way to make the DX hobby challenging and fun. I do.

Part Two: A Beginner’s Guide to ALE

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Many thanks to SWLing Post contributor Don Moore–noted author, traveler, and DXer–who shares the following post:

A Beginner’s Guide to ALE: Part Two

By Don Moore

In the first part of this series, I explained what the digital ALE mode is and looked at an easy way to get started monitoring ALE stations. In part three, I’ll look in detail at the dozens of countries and hundreds of stations that can be logged in ALE mode. But first, let’s look at a way to let software do the hard work in adding those hundreds of stations.

The Black Cat Approach

Run by longtime DXer Chris Smolinski, Black Cat Systems is a provider of over two dozen quality software programs for radio hobbyists. The one we’re interested in is the Black Cat ALE Vacuum Cleaner. The name describes exactly what it does. The user feeds it a large number of SDR spectrum recordings, and the Vacuum Cleaner sucks up the ALE DX and lists them in a file.

Let’s step through the basics of using the program. But first, you need at least an hour or two of SDR spectrum recordings covering frequencies with lots of ALE traffic. Some of my favorite ranges are 7500-9200 kHz, 10100-11500 kHz, and 15500-16500 kHz.

Here’s the main screen on the Vacuum Cleaner:

I recommend you check both USB and LSB. In the logs reported to the Utility DXers Forum, about 97% of all ALE transmissions are in USB mode. From my experience, if LSB is unchecked, the Vacuum Cleaner will step through the files about twenty percent faster, but you will miss a tiny number of stations.

The kHz settings determine how finely the application will tune in looking for ALE signals. I recommend just checking x.0kHz and x.5kHz. Almost all ALE signals on shortwave are transmitted on frequencies that end in either point-zero or point-five kilohertz. The main exception is the US Department of State, which uses frequencies ending in point-six kilohertz (e.g., 8058.6 kHz). Fortunately, the one-hundred Hertz difference from the point-five kilohertz setting isn’t enough to make a difference except maybe with the weakest of signals.

The next step is the Settings, which are found under the Edit menu. Most values can be left at the defaults.

At the top, the number of decoding threads should be no more than the number of cores that your CPU has. Check the Auto Log box, then enter a destination path to record logs to a file. (Otherwise, the logs that show up in the window will be gone when you close the program.) Next, select the file format of the SDR program used in making the I/Q recordings. Finally, set the file format for your logs. I prefer the single tab format so that I can later import the logs into Excel and sort by frequency.

Now it’s time to decode. Under the File menu, select Open I/Q Files and browse to a folder of spectrum recordings to decode. Click on Open in the file selection box, and the Vacuum Cleaner will start decoding the files. Now take a break and come back in fifteen or twenty minutes. The main screen should look like this.

The current settings and the frequencies being scanned are displayed at the top, under the settings checkboxes. There are actually only 1232 distinct frequencies in that range, but the number is doubled as each one is being checked in both LSB and USB. Below that, the output window lists each file as it is being scanned and ALE logs as they are found. (But be sure you are also recording these to a text file.)

To see a list of files still in the queue, select File > Show I/Q Files Awaiting Processing. After a few files have been processed, this will also show an estimate of how much time is needed to complete the queue. To add additional files to the queue, select File > Pause Processing, add the files, and then select File > Resume Processing. Note that the Vacuum Cleaner processes files in date/time order. If you add files that were recorded earlier, they will go to the front of the queue.

How Long Does This Take?

In the above image, notice that after each file is finished, the time taken to decode it is displayed. These files were all exactly 326 seconds long, and the first one took 262 seconds to decode for a speed of 1.24x actual time. That may not seem important, but it depends on how much you have to decode. In a couple of days of serious DXing with my three Airspy receivers, I can easily accumulate a couple of terabytes of spectrum recordings.

Processing time depends on several factors. The first is the bandwidth/sampling rate. Those files above were recorded with SDR-Console at 768 kHz wide. All other things being equal, a narrower sample will process faster and a larger one more slowly. Depending on the band being monitored, I sometimes record with my Airspys at the 912 kHz bandwidth. Those typically take about 25% longer to decode than 768 kHz files.

Another factor is whether or not the Vacuum Cleaner has to share processing power with other running applications. That slows things down. I mostly decode overnight or at times when I’m not otherwise using the laptop. Under those conditions, my 768 kHz files decode at 1.75x and my 912 kHz ones at 1.45x. But those numbers are for my nearly four-year-old main laptop. An older laptop I have at home tops out at around 1.40x on 768 kHz files with nothing else running. If you have a high-performance gaming laptop, you should get much better numbers than I.

Then there are differences between the various SDR applications in how they store data. I won’t go into the technical details that Chris explained to me, but SDR-Console is more efficient in this regard. In my own testing, I found that files of similar bandwidth and time length recorded with SDR-Console decode at least fifty percent faster than those recorded with the default Elad and Perseus software. I’m satisfied with SDR-Console, so I haven’t tried any other programs. If you have other favorite SDR applications, I suggest doing some comparison tests to see what works best for you.

One application that you shouldn’t use is HDSDR. Chris didn’t have good documentation on the file format for this one and wasn’t fully successful in reverse-engineering it. The Vacuum Cleaner will work with HDSDR, but almost all the callsigns that it finds will be errors. And that brings us to an important question.

How Accurate Is It?

When I started using the Vacuum Cleaner, my main concern was whether it would miss valid signals. There was only one way to find out, so I ran several tests. I would give the Vacuum Cleaner a few hours of I/Q recordings to decode, and then I would process the same recordings manually using Sorcerer, as described in part one. Black Cat not only correctly identified every single ALE transmission that I found with my eyes but went way beyond that. It also found and decoded weak and noise-covered signals that I couldn’t see in the Data Analyzer window but were there when I played them back.

As Chris points out in his documentation, the emphasis on weak signal detection does cause the application to sometimes falsely report bogus callsigns. Some of these are produced by random noise, fooling the system. Others come from poorly received signals. He could have taken a ‘high confidence’ approach and only presented callsigns that had been clearly received. But that would have meant some valid callsigns not being reported. Instead, he went with displaying everything. It’s up to the user to weed those out.

If the decode doesn’t contain any of the keywords (TO, TIS, and TWAS) then it’s probably an error. But poorly received signals can cause partial and incorrect callsigns to be reported with a keyword. Spotting those just takes the knowledge and practice that comes from using the program and ALE reference materials. (That’s the topic of part three.)

Is It Worth the Price?

Black Cat ALE Vacuum Cleaner is a high-quality software available for Windows and macOS, and you can try it before buying. The cost is $99.99.

Is it worth it? If all you want to do is sample what ALE is all about, then probably not. But if you get serious about ALE monitoring and want to add hundreds of ALE stations to your logbook, this is the way to do it. I am 100% satisfied with the Black Cat ALE Vacuum Cleaner. I’ve decoded several thousand hours of I/Q files with it over the past few years. (When running multiple SDRs at a DXpedition, it’s easy to accumulate seventy or eighty hours per day.) The program also has a few other tricks I haven’t covered. For example, it is possible to actively monitor a folder and decode I/Q recordings as they are created.

In part three of this series, I’m going to take an in-depth look at the countries and stations that can be logged in ALE mode. Once you’ve seen how much DX there is to log, you might just be convinced, like me, that the program is worth the price. And you married guys can tell the wife that you’re buying a new vacuum cleaner that only you will use, hi!

The Vacuum Cleaner isn’t the only program that Chris has for ALE monitoring. Black Cat ALE is a different program that does live monitoring of up to twenty-four ALE frequencies simultaneously with SDR-Console, assuming your laptop has the resources to handle that.

Finally, Chris tells me that he’s been experimenting with using the Vacuum Cleaner with wide-bandwidth I/Q recordings on high-end laptops. On his M4 Max MacBook Pro, he’s able to process 32-MHz wide recordings at about 0.50X real time and 16-MHz wide recordings at about 0.97X real time. As he says, it won’t be long until it will be possible with the right equipment to monitor the entire HF spectrum for ALE signals in real time. And that will be fun!

Part One: A Beginner’s Guide to ALE

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Many thanks to SWLing Post contributor Don Moore–noted author, traveler, and DXer–who shares the following post:

A Beginner’s Guide to ALE: Part One

By Don Moore

To me, part of the excitement of DXing has always been logging new stations. From the very beginning (over fifty years ago), I went after shortwave broadcast (SWBC), medium wave, and voice utility DX. Up until the mid-90s, I usually averaged logging one new SWBC station per week. Today, it’s hard to add more than one or two each year. There are also far fewer voice utility stations on the air today. At least medium wave is still going strong. Several years ago, my quest for logging new stations on the shortwave frequencies got me involved in DXing digital utility stations. I wrote an article here on monitoring DSC stations: https://swling.com/blog/2022/11/guest-post-monitoring-digital-selective-calling-dcs-with-yadd/).

But DSC is just one of several digital modes that I’ve been playing around with. The one that I’ve found most interesting – and the one that has yielded hundreds of new stations in numerous countries – is ALE.

Now, I am not an expert at monitoring ALE. I’m just an advanced beginner. But I think I know enough to help other beginners get started. And if you are an ALE expert reading this, I welcome your additions, corrections, and even criticisms to the comments section. I still have a lot to learn, too.

What is ALE?

Ever since the early days of radio, one of the most important uses of the shortwave spectrum has been two-way communication. It provides a means for an organization’s far-flung offices or bases to communicate without relying on external infrastructure. That remains true even today because satellites can malfunction and evil powers can cut undersea cables.

But shortwave isn’t consistent. The frequencies that work best between any two points will vary by time of day, time of year, solar conditions, and a host of other factors. In the old days, radio operators had to understand radio propagation to make an educated guess as to the best frequency to use to reach a particular distant station. Sometimes they guessed wrong, and stations would struggle to communicate or maybe not even connect. ALE, or Automatic Link Establishment, was designed to make two-way shortwave communication as simple as making a telephone call. Depending on your point of view, it has taken the guesswork out of frequency selection … or made it so easy that any dummy can be a radio operator.

In an ALE system, each station is assigned a unique identifier and the network has a set of preconfigured frequencies spaced throughout the shortwave spectrum. For example, here’s a partial list of frequencies and stations for the United States Air Force, one of the most active ALE networks.

USAF Common Frequencies: 4721, 5684, 5702, 6715, 6721, 8968, 9025, 11181, 11226, 13215, 15043, 17976, 18003, 23337, 27870 kHz

Most Active USAF Stations

ADW Andrews Air Force Base, Maryland, USA
AED Elmendorf Air Force Base, Alaska
CRO Croughton Air Base, United Kingdom
GUA US Air Force Base, Guam
HAW Hawthorn Air Force Base, Ascencion Island
HIK Hickman Air Force Base, Hawaii
ICZ US Air Force Base, Sigonella, Sicily, Italy
JDG US Air Force Base, Diego Garcia Island
JNR US Air Force Base, Salinas, Puerto Rico
JTY US Air Force Base, Tokyo, Japan
MCC Beale Air Force Base, California, USA
OFF Offutt Air Force Base, Nebraska, USA
PLA Lajes Field, Azores

The key to the system is a piece of software called the ALE controller. At periodic intervals, the ALE controller at a particular station, say PLA, will loop through the frequencies and send a “sounding” out on each one. That’s just a short digital identification burst saying “This is PLA!” Here’s a recording of an ALE sounding.

That’s not the kind of signal that anyone would enjoy listening to all day. Fortunately, no human being has to do that. Instead, all the other controllers in the network are monitoring every frequency and automatically make note of how well PLA is received (or not) on each channel. Now, if someone at Offutt Air Force Base needs to send a message to Lajes, they just go to their ALE controller and enter “PLA.” The system will select the best frequency to use based on the most recent observations. That’s the basic explanation. If you want to understand more, see the links at the bottom.

Monitoring ALE

You can’t DX ALE with your ears. A computer program has to do it for you. There are several hobby programs that do the job, and I’m going to look at two of them. The first one will get you started, and the second one will take your ALE DXing to the top.

I began with Sorcerer, a free program that decodes several dozen digital modes. See the links below for downloading. The program doesn’t need to be installed. Just unzip the file and place the executable in a suitable location. Next, you need an SDR and an SDR application. I prefer SDR-Console for digital work, but any SDR program will work if you can feed the audio into a virtual audio cable. And that’s the other thing you need – a direct audio connection from the audio output of your SDR application to Sorcerer. There are several similar products available, but I recommend VB-Cable. Your first VB-Cable is free, and you only need one to run Sorcerer. If you want to expand, you can buy more VB-Cables later.

Here’s the main window that opens when you start Sorcerer.

The first time you use Sorcerer you will need to connect it to your VB-Cable. On the menu select File then Options. Find the cable under the Soundcard list and save.

Open your SDR application and tune it to 11181 kHz. Set to USB mode with a filter value of around 2.8 kHz. That is one of the most heavily used frequencies by US Air Force bases around the world. Wherever you are, something should be received. Next, set the audio output of your SDR application to go to VB-Cable. In SDR-Console that’s done by a drop-down box under the current frequency. Next, slide the volume level all the way up.

Now go back to Sorcerer and confirm you are getting audio from the SDR application.

Now select Add Decoder from the top menu in Sorcerer. Then select SELCALL on the left side and scroll down and double-click to select MID-STD 188-141A ALE from the options.

That will open a large decoder window, which you can resize as needed.

Now, go get a cup of coffee and come back in about thirty minutes.

Sample Sorcerer Output

Let’s take a look at some sample output from Sorcerer. These loggings were made on 7915 kHz, a frequency used by the Carabineros (National Police) in Chile. First, Sorcerer shows the time and date the decoding was done per the current time on the laptop. If you are monitoring live, those are the correct date and time of the reception. For the record, I was decoding from SDR spectrum recordings in these examples, so the times and dates are not the real ones. (I got the real ones from the spectrum recordings.) TWS stands for “This Was” and EOM for “End Of Message.” ILLAPEL and TALTAL are the station identifications, which in this case correspond to two Chilean cities. Note that sometimes the end of the ID can be cut off if reception isn’t clear.

These next loggings are from the national police of Colombia on 7560 kHz. Villavicencio is a city east of the Andes, and Sumapaz is a national park in the remote mountains south of Bogotá.

Here is a string of loggings on 7527 kHz, a frequency used by the US Coast Guard and other US government agencies. But here we have a TO, which means someone is trying to call X09. That happens to be a C-27J Spartan, a medium-range surveillance aircraft used by the US Coast Guard. Who’s doing the calling shows up in the final line. TIS (“This Is”) is a variation on TWS. LNT is the identification for CAMSLANT, the big US Coast Guard station in Portsmouth, Virginia.

The Limits of Single Frequency Monitoring

DXing live and monitoring one highly active frequency at a time with Sorcerer makes for a good introduction to ALE. However, if you just stick to monitoring easy frequencies like the USAF ones, you’ll get a lot of logs, but it won’t take long until you feel as if you’ve gotten everything. There are hundreds more ALE frequencies out there, such as the Chilean and Colombian police ones. But those are less active and might only be received at your location when conditions are just right. If you go after those by live monitoring with your SDR parked on a single frequency, you’ll spend a lot of days without getting a single hit.

What is needed is a way to cast a wide net to catch all the activity in a particular band. The idea I came up with was to use the Spectrum Analyzer feature of the SDR-Console program. See my article on this highly useful feature for an understanding of how this works.

Using an Airspy HF+ Discovery, I would make several hours of spectrum recordings and then use the Spectrum Analyzer to visually find the ALE signals. Here’s a string of three long ALE bursts on 7953 kHz and a single weaker one on 7991 kHz. (Some other digital modes look the same on screen.)

I just had to click on a signal to play it into Sorcerer to get the ID. The process worked really well, and I found a lot of stations this way. But it was also tedious and time-consuming. I wanted something better … something that did the hard work for me. That’s what technology is for, right?

Stay tuned for Part Two …

Mystery Station … Solved

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By Don Moore

About two weeks ago I reported a mystery station identifying as the Duyen Hai Vietnam Information Station broadcasting in Thai on 8101 kHz. There is now enough information to identify who is behind the station and where it is coming from.

First, thanks to California DXer Ron Howard for his Internet sleuthing. Ron found a PDF file that specifically lists 8101 kHz as being used by the Hai Phong station in the Vishipel network, the Vietnam Maritime Communications and Electronics Company. This is a government-owned company that provides various services to the maritime industry. One of those services (and the one we’re interested in) is a network of thirty marine radio stations strung along the Vietnamese coast from north to south. The stations provide two-way marine radio communication and twice-daily scheduled weather broadcasts. All the stations use VHF and seventeen also use HF.

Vishipel’s weather broadcasts are listed on the DX Info Centre website and I had been monitoring those in my travels here in Southeast Asia. I suspected Vishipel was connected to this station but Ron found definitive proof that they use 8101 kHz and that the frequency comes from their station in Hai Phong. He also found this map showing all the coastal stations in the Vishipel network.

I’ve been wanting to record the station again, but my current location is not suitable for DXing. Since December 15th, I’ve been staying in the old city in Chiang Mai in northern Thailand. But a few days ago, I made a two-day DXpedition to a rural location outside the city and made a terabyte of spectrum recordings with my three Airspy HF+ Discovery SDR receivers.

It will take me a while to go through all that DX, but I’ve already checked for Duyen Hai. I had a very good signal from it on 8101 kHz at 1214 UTC on 08 January 2026. This broadcast was eleven minutes long, which is a few minutes shorter than the ones previously monitored. Here’s a recording of the entire broadcast.

The reception was good enough that Google Translate had no problem turning the spoken Thai into written English. The program was about new EU requirements around animal welfare. But the broadcast content wasn’t my focus. This was the first time I had good copy of the entire broadcast and I wanted to hear the ending. Here is a translation of the sign-off announcement.

Hello, ladies and gentlemen, today’s broadcast is over. Thank you for your attention, fishermen and audience. Our program is broadcast daily on the frequency 8101 kHz at 07:05, 19:05, and on the frequency 7996 kHz at 12:05. People can also contact their families and relatives via these two frequencies on all days of the week. I wish you all safe and effective sea trips. Hello, and see you again.

The wording is important for those of us who like to neatly categorize things. It proves that this is an intentional scheduled broadcast to an audience and not just a utility station unofficially relaying a broadcast. It’s the difference between whether it can be counted as a shortwave broadcast (SWBC) station or as a utility station. This ticks all the requirements to be counted as SWBC. Indeed, as a broadcast from Vietnam in Thai to a Thai audience it could even be considered as an international broadcaster!

The times in the announcement are local for Southeast Asia and correspond to 0005 and 1205 UTC on 8101 kHz and to 0505 UTC on 7996 kHz. I also found the program in my spectrum recordings coming on at 0019 UTC on 09 January. Obviously, they don’t care too much about beginning on time. Every broadcast I’ve monitored has begun ten to fifteen minutes late.

Unfortunately, I can’t check for the 0505 UTC broadcast as I didn’t make any spectrum recordings in that frequency range at that time (local noon). I’ll be sure to get some at my next opportunity. I also have questions about the 7996 kHz frequency. It isn’t listed in the Vishipel PDF, but it was listed as being used by the Nha Trang station in the 2017 Klingenfuss Utility Guide (the most recent I have).

Unless you’re in Southeast Asia, you won’t get a signal as good as the recording. But the Duyen Hai always uses the same woman announcer and the same musical interludes. Even if you just have a weak static-ridden signal, you should be able to match the music to that in the recording. So, can you catch this one at your location?

LINKS

Schedule of HF marine voice weather broadcasts at DX Info Centre. The Vietnamese listings are found under frequencies 7906 and 8294 kHz. https://www.dxinfocentre.com/marineinfo.htm
PDF file with full schedule for Vishipel stations. Times are local (Southeast Asia) times. Subtract seven hours to get the UTC time. This also includes the frequencies such as 8101 kHz that are normally used for two-way voice communication. https://vishipel.com.vn/pic/general/files/Bang%20Tan%20so%20TTDH.pdf
This 35th anniversary video from 2017 shows several of the Vishipel stations. https://www.youtube.com/watch?v=oTSKzsA3IXE
Four-minute English slide show on YouTube about Vishipel. It moves fast so you will need to pause to actually read the slides. https://www.youtube.com/watch?v=0htHphnnFgk
Vishipel English website (loads very slowly) http://en.viship

Don Pushes Portable Antennas Further: Loop Size, Performance, and Real-World Limits (Part 2)

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Many thanks to SWLing Post contributor Don Moore–noted author, traveler, and DXer–who shares the following post:

Two Portable Antennas for Remote DXing (Part Two)

By Don Moore

In my initial comparison of the PA0RDT mini-whip and the MLA-30+ MegaLoop, the mini-whip performed best on medium wave and the lower shortwave bands, while the loop worked better on the higher bands. But, I wondered, why should the MLA-30+ be restricted to that small steel loop? The wire loops I use with my Wellbrook ALA-100LN typically range from twenty to fifty meters in circumference.

I threw a twenty-five-meter wire over a tree branch and formed it into a delta with the MLA-30+ in the bottom center. Remember, I was testing in the northern Chicago suburbs. My SDRs were completely overloaded. Medium wave was useless and I had strong MW stations all over the shortwave bands. The MLA-30+ doesn’t have the same strong-signal handling capabilities as the Wellbrook. And there are a lot of strong medium wave signals in the Chicago suburbs.

So I took that wire down and replaced it with a loop of twelve meters circumference.

That did the trick. I had lots of signals on medium wave without the overloading. Here’s what the upper end of the MW band now looked like with the MLA-30+.

For comparison, here’s the same wire loop using the Wellbrook ALA-100LN. The Wellbrook has a slightly lower noise floor but otherwise the signals are about the same.

Out of curiosity, I replaced the Wellbrook power unit with the Bias-T from the MLA-30+ but left the Wellbrook antenna head unit in place. With this hybrid setup there’s no visible difference with the full Wellbrook.

I was satisfied with my findings but I still wondered how much wire the MLA-30+ could handle. A few weeks later I ran some more tests in Kansas, where I knew the dial wouldn’t be as crowded. The MLA-30+ easily handled a 25-meter delta loop without overloading.

Two weeks after doing the Kansas tests I was at a DXpedition in rural western Pennsylvania. The MLA-30+ worked fine with a 40-meter circumference loop, other than being a tad noisier than the Wellbrook with the same wire. So how much wire you can use with the MLA-30+ components depends on how strong your local medium wave stations are.

Findings

From the SDR images above it would be easy to conclude that with the right length of wire an MLA-30+ is just as good as a Wellbrook ALA-100LN even though it is significantly cheaper. But that’s not the full picture. Back in the 1990s my Drake R-8 cost about three times what my Sony ICF-2010 did. All other things being equal, I would say that 95% of the DX heard on the Drake could have been heard equally well on the Sony. I wanted the Drake for the other five percent.

I have no doubt that if I did a very careful head-to-head comparison of the two units under serious DX conditions on the same wire that the Wellbrook would get things the MLA-30+ couldn’t. But I suspect the difference would be around that five percent mark. I’m willing to accept that tradeoff for an effective cheap light-weight travel antenna. And the MLA-30+ is like having two antennas in one. I can use it with the steel loop in limited space situations or with a larger wire loop when I have access to some garden space with a tree. Together, the MLA-30+ and the PA0RDT make the perfect DX travel antennas.

The only thing I didn’t like about the MLA-30+ was that pre-attached coax cable. It’s not the best quality and I’d rather carry my own cable. I’m not very handy with a soldering iron in tight spaces but at our recent DXpedition my friend Bill Nollman replaced the coax with a BNC jack for me.

The MLA-30+ now looks like this when connected to a wire loop.

Finally, I should address powering the MLA-30+ via USB. While it can be connected to a spare USB port on your laptop, I found doing that sometimes introduced a tad more noise. Instead I’ve been using one of those battery packs used for recharging cellphones. Mine is rated at 6700 mAh and it can power the MLA-30+ for over 48 hours before needing a recharge. But be sure to test yours before doing any serious DXing. I’ve read that some power packs have a minimum required power draw and will automatically shut off if the draw is too low.

Another Option?

While I was finishing this article I heard about another option from my friend Guy Atkins. This antenna is a combination of the YouLoop with a low-priced Chinese made clone of the LZ1AQ amplifier. Some users say it’s better than the MLA-30+. Guy says it works well on shortwave up to 16 meters but he hasn’t tried it on medium wave. Guy says it’s a “low price, good value” antenna. I’m traveling in Southeast Asia for the winter but will definitely have to try this antenna when I get back to the USA. So maybe there will be a follow-up article next summer.

Links

[Note: Amazon links are affiliate and support the SWLing Post at no cost to you.]

Info on ordering a quality PA0RDT from Roelof Bakker. (Other cheaper versions have had issues with quality control.)

https://dl1dbc.net/SAQ/miniwhip.html

There are various versions of the MLA-30+ and the original MLA-30. This is the version that Mark Taylor recommended and that I bought.

https://amzn.to/3MEKjPY

There are numerous YouTube videos on using and modifying both versions of the MLA-30+. This one shows how to replace the coax with a BNC jack.

https://www.youtube.com/watch?v=OAqh2Lawwdc

Here’s the Amazon link for the YouLoop/LZ1AQ antenna that Guy has.

https://amzn.to/4s1RB09

And the same antenna on Ali Express.

https://www.aliexpress.us/item/3256808527623276.html

Portable Antennas for Serious DXing: Don’s Field Tests from Parks to the Open Road (Part 1)

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Many thanks to SWLing Post contributor Don Moore–noted author, traveler, and DXer–who shares the following post:

Two Portable Antennas for Remote DXing (Part One)

By Don Moore

Once upon a time, I had a traditional DX shack with an L-shaped desk and shelves of receivers, radio gadgets, and DX books. Everything I wanted or needed as a DXer was right at hand. Then I retired and was finally able to pursue my lifelong itch for serious travel. But there was no way to carry that DX shack along with me. Fortunately, modern technology was there to help. SDRs are significantly more travel-friendly than my old Sony ICF-2010 (let alone the Drake R-8). Instead of books and bulletins, my DX reference materials are websites and PDF files on my laptop.

I spend several months a year traveling internationally with just a suitcase and knapsack. That doesn’t leave much room for DX equipment. Several years ago I described my approach to vagabond DXing in an article here.

https://swling.com/blog/2019/03/radio-travel-a-complete-sdr-station-for-superb-portable-dxing/

Since writing that article in 2019, I’ve continued to work on making my portable DX shack better and more compact. Recently, I replaced the Elad FDM-S2 with three Airspy HF+ Discovery SDRs. Not only are they smaller and lighter, but I can record three different band segments at once. Next up was rethinking my travel antennas. A wire loop with the Wellbrook ALA-100LN is still, in my opinion, the best travel antenna. But the components are heavy and are now irreplaceable since they are no longer made. So over the summer, I set about testing and comparing both old and new options. But you don’t have to wander the globe for my findings to be useful to you. This can be just as helpful for DXing from a nearby park. That’s how I did my testing.

I spent the past summer staying at an AirBnB in the north Chicago suburbs. I wanted a better location for testing so I checked out parks in the area and finally settled on Preserve Shelter B (42.26797, -87.92208) at the Old School Forest Preserve, east of Libertyville in northern Illinois. The shelter was entirely wood, with standard asphalt shingles (rather than steel), and had no nearby power lines. I made four daytime DXpeditions there to do some utility DXing and to run my tests. Here’s a photo of my setup.

I decided I should rerun the tests at least one other location. So while driving across the US in mid-October, I stopped for a few hours one morning at Park Shelter A (39.11144, -94.86629) in Wyandotte County Park, just west of Kansas City, Kansas. There, I just had a minimum setup.

The Antennas

So, what were the antennas I was testing? The first was the tried-and-true PA0RDT mini-whip from Roelof Bakker. The PA0RDT is described in my 2019 article and is probably the most portable quality antenna you can get. To power it I use a battery box and eight rechargeable lithium-ion AA cells.

For the traveling DXer, setting up the PA0RDT is as easy as it comes. I just attach the coax cable and throw it over a support, such as a picnic shelter beam or a tree branch.

But I’ve always believed that the best antenna is another antenna. That is, every antenna works differently, and therefore the more options you have, the more likely you will have something that works well in any situation. So if I wanted to leave the Wellbrook at home, what might complement the PA0RDT? I contacted my friend Mark Taylor, who I knew had a large collection of the various inexpensive Chinese-made amplified loops. With his help, I settled on the MLA-30+ MegaLoop from DmgicPro.

This antenna consists of a steel wire loop that connects to terminals on the amplifier box. The amplifier has a ten-meter coax cable, which in turn is connected to a small bias-T power supply, which gets its power via a USB connection. The MLA-30+ is designed to be used in a permanent installation with some sort of vertical support, such as a PVC pipe. Some users replace the wire loop with copper tubing.

Those options aren’t practical for me, and simply hanging the antenna from the top would cause the steel loop to stretch and deform. So I came up with the idea of tying a strong cord from the top to the bottom of the loop so that the cord, and not the loop, bears the weight. To hang the antenna, I throw the cord over the support, attach the antenna, and then pull it up into place. That works well if you have rear support to hold it in place, such as the beams of a picnic shelter.

It’s a bit more difficult to mount the MLA-30+ in a tree.

Comparing the Antennas

I ran comparisons between the antennas several times at Old School Forest Preserve and then again at Wyandotte County Park. The results were practically the same every time. The images below were made at Old School unless otherwise stated.

The PA0RDT was designed to be a good performer on longwave and medium wave. Unsurprisingly, it shows a lot of signals on the upper end of the medium wave band, even during the daytime. Except for being non-directional, the PA0RDT is an excellent MW antenna.

The MLA-30+, on the other hand, isn’t good for much beyond hearing the strongest local signals on medium wave.

When I ran these tests in the late morning, WWV on 5 MHz was the only signal in the 60-meter band. It had a very listenable signal on the PA0RDT.

But on the MLA-30+, WWV was barely there.

Likewise on 49 meters, CFRX on 6070 kHz was very clear on the PA0RDT but barely listenable on the MLA-30+. But when I moved up to 31 meters, the difference between the antennas mostly disappeared, as in these images made in Kansas. The PA0RDT is top and the MLA-30+ on the bottom.

On 25 meters, the PA0RDT is picking up a lot of noise and the signals are not that strong. Nor were signals very strong on 19, 16, 0r 13 meters.

However, on 25 meters with the MLA-30+ there isn’t much noise and the signals are booming in. And 19, 16, and 13 meters likewise had strong signals.

So the PA0RDT is clearly the best antenna for MW and the lower shortwave bands, but it doesn’t do as well on the higher bands. This wasn’t a surprise to me as I’ve always felt that the PA0RDT underperformed above nine or ten Megahertz. The MLA-30+ was abysmal at the lower frequencies but worked better or just as well in the middle and higher shortwave bands. The best antenna is another antenna. Each one performs better in different situations. But I couldn’t help but wonder … was the problem with the MLA-30+ that small steel wire loop?

Look for Don’s Part 2 article next weekend on the SWLing Post!

Meeting WavViewDX Developer Reinhard Weiß, and Visiting Akihabara With Him (A Totsuka DXers Circle Article by Kazu Gosui)

Meeting WavViewDX developer Reinhard Weiß, and Visting Akihabara With Him

by Kazu Gosui

I first learned about WavViewDX in January of this year on the mailing list of the American radio club IRCA. It was described as “analysis software compatible with I/Q WAV recordings created with almost all SDR software,” so I was intrigued. I quickly downloaded it and tried it out, and I was immediately impressed.

In early February, I emailed the developer, asking, “I’m amazed at how easy it is to use and how powerful it is. It works fine with PERSEUS and AirSpy HF+, but are there any plans to support WiNRADiO’s DDC format?” Reinhard Weiß (hereafter referred to as Reinhard) responded that same day, “I’m actually currently working on adding support for WiNRADiO’s G33DDC. I should be able to send you a test version tomorrow.” The email carefully explained the import procedure and important points to note.

The text, the web page description, and the tone of the expression conveyed a sincere and attentive personality. The next day, I tried out the sample version and reported some concerns. Reinhard quickly fixed them, and where he couldn’t immediately fix them, he supported me by sending files via the cloud or screen capture videos. As I continued to request things like adding a shortcut for switching receive modes, I gradually became fascinated with WavViewDX and, before I knew it, became a heavy user.

The first email also asked, “I’m planning to visit Japan in May or June. Are there any ham or BCL (Broadcast Listener; SWL) events in Japan around that time?” In response, I suggested that if Reinhard could come to Tokyo, we could hold an offline meeting with members of TDXC! Through our exchange, I realized that Reinhard is quite knowledgeable about Japanese affairs. He knows Akihabara very well, and even knows Hard Off as a good place to get BCL radios. He loves hot springs and enjoys talking about Japanese food. When I asked him, “Is your wife Japanese by any chance?” he replied, “Yes.” No wonder he’s so knowledgeable! He should have told me sooner! (lol) So, we made an appointment for an offline meeting in Akihabara, Tokyo, in late May.

On the day, we met at the Electric Town exit of JR Akihabara Station. Our four attendees were Hiroo Nakagawa, Satoshi Miyauchi, Fumiaki Minematsu and myself. When I arrived at the meeting point five minutes early, they were already there. When I asked him, “Excuse me, Reinhard-san?” he replied, “Yes, that’s right,” in Japanese. His Japanese was fluent! Up until now, emails had been in English, as I don’t speak German, so I had no choice but to communicate in English… I was completely surprised because I had been counting on the others and Google Translate on my smartphone to converse in English! You should have told me sooner, Reinhard! (lol) Needless to say, from then on, the entire conversation was in Japanese. The meeting venue was a pub near the station. He could read the Japanese menu, and thanks to his wife, who is apparently a good cook, Japanese food was also OK, so no problem.

We spoke about radio and BCL. Reinhard started medium wave DX about three years ago. He has been interested in radio since he was a child and actually worked as a BCL radio broadcaster. He has had a long career. His job is developing debuggers for testing and verifying the operation of in-vehicle electronic devices and measuring instruments. He says that both his work and his hobby are focused on developing easy-to-use hardware and software integration. He developed WavViewDX while studying the programming language Python, and runs it at home using two PERSEUS devices.

He said he would be happy if many people use it. Currently, WavViewDX has 200 users, 25 of whom are active worldwide. Incidentally, the mailing list has 102 subscribers (as of June 10, 2025).

Over lunch, we had the opportunity to use WavViewDX on the PC we brought with us, and it was extremely valuable to have the developer himself explain how to use it, provide an overview of its functions, and explain the development concept. We also received copies of the German BCL magazine “Radio-Kurier” (a radio delivery service?). This magazine apparently publishes an astounding 2,000 copies per month, demonstrating the depth of Germany’s BCL population. The most active BCLs are few, and 80% of the articles are written by one person. That’s impressive.

The second half of the meeting was a tour of Akihabara’s famous shops. We visited the Radio Center rental showcase, Uchida Radio, Radio Department Store, Rocket, Fuji Musen, and Akizuki Denshi. Reinhard has a keen interest in vintage Japanese BCL radios and boomboxes, and his eyes lit up as he looked at rare radios and boomboxes. At Uchida Radio, he even negotiated the price of a radio cassette player he was interested in. Unfortunately, the deal fell through, but he apparently toured Hard Off stores around Tokyo the next day, so he must be a die-hard enthusiast. He also seemed to love the Fuji Wireless and Akizuki Electronics stores on the second floor, saying, “Their unique products are what keeps them going, and I can see why they’ve survived.” He bought a large breadboard (brand new!) for 50 yen on the second floor of Akizuki and then we took a break for tea in the cafe.

We had a great time chatting there, too. Reinhard is, in a word, a nice guy. A German who speaks Japanese, loves radio and BCL, and develops software for BCL—an extremely rare and valuable person. He’s fluent enough in Japanese to even tell jokes, and he’d laugh along with us at our old-man jokes. He was friendly and fun to talk to, and we shared the same values as fellow enthusiasts. It felt like we were old friends.

He apparently returns to Japan every year with his wife, but he hasn’t done a DX expedition yet. Maybe the next one will be the Chigasaki expedition?! So we parted ways, hoping to see each other again next year.

(l-r: Kazu Gosui, Satoshi Miyauchi, Hiroo Nakagawa, Reinhard Weiß, Fumiaki Minematsu) —Hiroo Nakagawa photo

(l-r: Kazu Gosui, Hiroo Nakagawa, Reinhard Weiß, Satoshi Miyauchi) —Fumiaki Minematsu photo

These English translations were prepared for IRCA’s DX Monitor, and are used with the kind permission of IRCA as well as of the authors and the editor of the Totsuka DXers Circle publication, PROPAGATION.