Category Archives: DX

Gary DeBock’s XHDATA D-808 loopstick model

Many thanks to SWLing Post contributor, Gary DeBock, who shares the following:

The 7.5 inch (19cm) loopstick XHDATA D-808 model was designed to be the ultimate AM-DXing (or Longwave DXing) travel portable, and can be built for a construction cost of around $30 US. It has already been used by numerous DXers to track down transcontinental and transoceanic AM-DX during overseas travel, and the orange plastic loopstick frame allows full operation of the whip antenna for FM and Shortwave reception.

The modification procedure isn’t difficult, and the full construction article is posted at

https://dreamcrafts.app.box.com/s/5d0pi85jfptgmrj4pd0jsmaybgb6gteh

A video demonstration of its daytime DX performance (compared to the stock model) has been posted on YouTube:

Build one, and join the fun! 🙂

Many thanks for sharing this, Gary! Your ultralight DXing creations are simply amazing!

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Guest Post: A synchronous detector crash course!

Many thanks to SWLing Post contributor, 13dka, who shares the following guest post:


Revisiting the Belka’s “pseudo-sync detector”: A sync detector crash course!

by 13dka

“It’s usually hard to assess whether or not a sync detector helped with a particular dip in the signal or not, unless you have 2 samples of the same radio to record their output simultaneously and compare.”*

That’s what I wrote about the “pseudo sync detector” in my review of the Belka DSP last year.

Since I was recently upgrading to the Belka DX in order to pass on the Belka DSP to a friend, I had briefly two examples of almost the same radio on the table at the dike. I tuned them to the same stations and recorded some audio clips with one radio on sync detector, the other in regular AM mode, to answer the question whether or not sync has “helped with a particular dip in the signal”. Then I thought that demonstration would be an opportunity to try an explanation on what exactly (I think) sync detectors are all about anyway, hoping to find a middle ground between “technical” and “dumbed down beyond recognition”.

The trouble with sync detectors

Perhaps no component of a shortwave receiver is surrounded by so much misconception and confusion as sync detectors. Full disclosure: Until quite recently, I had an, at best, vague concept on what they do myself. It seems it’s not so much that people don’t know how they work, what they actually do when they work is where the ideas often diverge. Continue reading

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The Icom IC-705: Is this really a new holy grail SWL/BCL receiver?

Many thanks to SWLing Post contributor, 13dka, who shares the following guest post:


The Icom IC-705: Is this really a new holy grail SWL/BCL receiver?

by 13dka

When Thomas got wind of its development in 2019 he immediately asked “could the Icom IC-705 be a shortwave listeners holy grail receiver?”. I usually wince a little when I hear “holy grail” because it means very different things to different people, it’s also a moving target with many people aiming at the spot where it was decades ago. But Thomas certainly had a very level-headed assembly of technical performance, quality and practicality requirements in mind when he used that term, and I thought he might be onto something!

There are some excellent, trustworthy reviews of the IC-705 out there. The following is not one of them, I just want to share an opinionated breakdown on why I think this is an interesting radio for SWLs/BCLs indeed, also deliberately ignoring that it’s actually a transceiver.

Jumping shop

While the era of superhet/DSP-supported tabletop holy grails ended with the discontinuation and sell-off of the last survivors more than a decade ago, powerful PC-based SDR black boxes were taking over the mid-range segment and it became very slim pickings for standalone SWL receivers: Thomas just recently summed up the remaining options here.

Between the steady supply of inexpensive yet serviceable Chinese portables, upgraded with a least-cost version of DSP technology, and the remnants of the high end sector there’s very little left to put on the wish list for Santa – that doesn’t need to be paired with a computer that is.

No surprise that SWLs/BCLs in search of new quality toys with tangible controls are taking a squint over the fence to the ham transceiver market: Hams are still being served the best and the latest in radio technology in all shapes and sizes, and even entry-level rigs usually come with feature-rich general coverage receivers. But transceivers never had SWLs much in their focus in the past decades, and particularly not BCLs: Frontend adaptation, additional AM filters, switches and functions would’ve meant increasing costs and so transceivers were never perfected for that purpose. DSP and SDR technology allowed for improvements on that without actually adding (much) hardware and so some interesting alternatives surfaced in the past years, but most of them still come with little downers, at least for BCLs.

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Gary DeBock’s 2021 Ultralight Radio Shootout!

Many thanks to SWLing Post contributor, Gary DeBock, who shares his extensive 2021 Ultralight Radio Shootout.

This is truly a deep dive featuring five popular ultralight portable radios and examining mediumwave, shortwave, FM, and AIR Band performance.

The review is an amazing 40 pages long! In order to display the entire review, click on the “Continue reading” link below.


2021 Ultralight Radio Shootout

Five Hot Little Portables Brighten Up the Pandemic

By Gary DeBock, Puyallup, WA, USA             April 2021

Introduction   The challenges and thrills of DXing with pocket radios have not only survived but thrived since the Ultralight Radio Boom in early 2008, resulting in a worldwide spread of the hobby niche group. Based upon the essential concepts of DXing skill, propagation knowledge and perseverance, the human factor is critical for success in pocket radio DXing, unlike with computer-controlled listening. The hobbyist either sinks or swims according to his own personal choices of DXing times, frequencies and recording decisions during limited propagation openings—all with the added challenge of depending on very basic equipment. DXing success or failure has never been more personal… but on the rare occasions when legendary DX is tracked down despite all of the multiple challenges, the thrill of success is truly exceptional—and based entirely upon one’s own DXing skill.

Ultralight Radio DXing has inspired spinoff fascination not only with portable antennas like the new Ferrite Sleeve Loops (FSL’s) but also with overseas travel DXing, enhanced transoceanic propagation at challenging sites like ocean side cliffs and Alaskan snowfields, as well as at isolated islands far out into the ocean. The extreme portability of advanced pocket radios and FSL antennas has truly allowed hobbyists to “go where no DXer has gone before,” experiencing breakthrough radio propagation, astonishing antenna performance and unforgettable hobby thrills. Among the radio hobby groups of 2021 it is continuing to be one of the most innovative and vibrant segments of the entire community.

The portable radio manufacturing industry has changed pretty dramatically over the past few years as much of the advanced technology used by foreign companies in their radio factories in China has been “appropriated” (to use a generous term) by new Chinese competitors. Without getting into the political ramifications of such behavior the obvious fact in the 2021 portable radio market is that all of the top competitors in this Shootout come from factories in China, and four of the five have Chinese name brands. For those who feel uneasy about this rampant copying of foreign technology the American-designed C. Crane Skywave is still available, although even it is still manufactured in Shenzhen, China—the nerve center of such copying.

Prior to purchasing any of these portables a DXer should assess his own hobby goals, especially whether transoceanic DXing will be part of the mission– in which case a full range of DSP filtering options is essential. Two of the China-brand models use only rechargeable 3.7v lithium type batteries with limited run time, which may not be a good choice for DXers who need long endurance out in the field. A hobbyist should also decide whether a strong manufacturer’s warranty is important. Quality control in some Chinese factories has been lacking, and some of the China-brand radio sellers offer only exchanges—after you pay to ship the defective model back to China. Purchasers should not assume that Western concepts of reliability and refunds apply in China, because in many cases they do not. When purchasing these radios a DXer should try to purchase through a reputable seller offering a meaningful warranty—preferably in their own home country.

One of the unique advantages of Ultralight Radio DXing is the opportunity to sample the latest in innovative technology at a very reasonable cost—and the five pocket radio models chosen for this review include some second-generation DSP chip models with astonishing capabilities. Whether your interest is in domestic or split-frequency AM-DXing, FM, Longwave or Shortwave, the pocket radio manufacturers have designed a breakthrough model for you—and you can try out any (or all) of them at a cost far less than that of a single table receiver. So get ready for some exciting introductions… and an even more exciting four band DXing competition!

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Paul Walker featured as a DXer and broadcaster on ABC Newcastle

Our friend and contributor here on the SWLing Post and the Shortwave Radio Audio Archive, Paul Walker, has been interviewed and featured on the ABC Newcastle program Drive with Paul Turton. It’s a great segment! (Congrats, Paul!)

I’ve embedded the audio from this segment below, but you can also listen via the ABC Newcastle website:

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1933 Aluminum disc recordings from a DXer in England

Many thanks to SWLing Post contributor, Mark (AE2EA) with the AWA, who writes:

Your loyal followers might be interested in this video of airchecks
recorded on aluminum discs in England of US broadcast stations in late
1933, from the Antique Wireless Museum.

From the AWA description:

These audio clips were recorded on aluminum discs using more of an embossing than cutting action. Reading an AWA Facebook post that the AWA doesn’t have the equipment or experience to digitize the very fragile audio information on these discs, radiodave78@aol.com volunteered to do so. He did a great job is highly recommended for your consideration as a service for archival digitization and restoration.

The discs were in Peter R. Testan’s collection because they included recordings of station WBBC in Brooklyn, NY that his dad, Peter J, started. As well as being a broadcast owner and engineer, Peter J. Testan was also a ham operator. Pictures of his ham shack were featured in a recent issue of the AWA Journal.

While the calls are identifiable, the other programming in these recordings is difficult to listen to. The Creative Director of a New York City radio station remarked after listening: “”It’s so funny because I have DXers sending me EXACTLY the same quality audio as on these discs. Nothing has changed in nearly 100 years!!!”

The audio quality in this video has been enhanced from the original aluminum disc recordings through the use of bandpass filtering, noise reduction and compression, with the goal of removing some of the artifacts of the recording process.

The Wikipedia entry for aluminum discs is pretty succinct: https://en.wikipedia.org/wiki/Aluminum_disc

If you enjoyed this video, consider becoming a member of the Antique Wireless Association at https://antiquewireless.org/homepage/membership/

Absolutely mazing! Thank you so much for sharing this, Mark!

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Michael pairs the Tecsun PL-990 and the AOR LA400

Many thanks to SWLing Post contributor, Michael Ye (BD4AAQ), for the following guest post:


In the Loop: PL-990 and LA400, a Perfect Match

by Michael Ye (BD4AAQ)

PL-990 and LA400

I have been a happy owner of Tecsun’s PL-880 world band receivers for years. In fact I have two PL-880 radios, one sitting at home and the other staying in my car. So, after Tecsun introduced the new model PL-990 in late 2020, it didn’t take me long to decide to purchase one. In this article I will discuss the Tecsun PL-990 receiver working with loop antennas, while referencing some relevant features of the PL-880.

Overall performance of the PL-990

Merely by its model number, it is easy to regard the PL-990 as an upgraded version of the already highly reputable PL-880. As expected, the PL-990 can very much be regarded as a combination of all the existing fine radio features of the PL-880 AND the music and bluetooth additions, with a number of improvements for instance in shortwave and medium wave performance. The ergonomic design of the PL-990 looks and feels different from that of the PL-880 in a number of ways. Although I may prefer the the more slim and elegant appearance of the PL-880, the PL-990 gives a more rugged and durable feeling, among other improvements over the older PL-880.

Working with loop antennas

The PL-990 and the PL-880 side by side

Living on the twelfth floor of a condominium in the crowded Shanghai, I have often been fascinated with loop antennas. As a licensed amateur operator, I have used the MFJ-1786X and have been impressed with its performance. On reception, I also find loop antennas appealing, as they are able to pull in weak signals while noticeably reducing electro-magnetic interference rampant in the urban environment. I have an unbranded shortwave loop antenna which I believe is based on and performs similarly with the AOR LA320. Despite its excellent performance, it is only good for the 5MHz – 15MHz shortwave range. So a few years ago when AOR launched the new LA400 wideband loop antenna, I bought one, which I often pair up with the PL-880 and other radios for shortwave listening, and get satisfactory results!

Antenna Switch on the PL-990

Now, back to the PL-990. When I first tried the PL-990 with the LA400, the results were generally good but not as good as as compared with using the same LA400 on my PL-880. This puzzled me for a day or so until I realised that the PL-990 actually has an antenna switch which the PL-880 does not have. The switch is used to toggle between an internal antenna (i.e. the built-in ferrite bar/telescopic antenna) and an external one (e.g. the AOR LA400). So a new PL-990 user who has often operated the PL-880 when first using the PL-990 could easily ignore the switch which should be pushed to “Ext” when plugging in an external antenna. This explains why the PL-990 may suddenly appear less sensitive than expected.

“Ext” antenna input for all bands

Contrary to the PL-880 whose external antenna socket is only good for shortwave signal input, the PL-990’s external antenna socket works with all bands, from long wave to FM. I found this to be an important and very useful change, and a pleasant surprise for my LA400, which covers a wide range of frequencies from long wave to medium wave to FM and up to 500MHz.

Once the LA400 is connected, the correct band selected, and last but not least the antenna switch turned to “Ext”, the PL-990 and the LA400 work like a charm in the indoor setting, remarkably better than the built-in telescopic antenna. With the loop connected, while there is not much to expect on the long wave band because of very few long wave stations remaining in the world, reception improves considerably on all other bands including on the medium wave and FM bands, as is also reflected on the upper right hand display of the signal strength and S/N ratio readings. Needless to say, performance on shortwave is as good as on the PL-880, if not better (again, remember to push the antenna switch to “Ext” when using it on the PL-990). Using the AOR loop on the PL-990 for FM reception is somewhat different as there does not seem to be a noticeable tuning point. Simply select the “Others” band, which appears to be broad enough for fair FM reception.

Tecsun AN-200 loop antenna

It is worth mentioning that I have a Tecsun AN-200 tunable medium wave antenna, which I have not used often. As its name suggests, it is for medium wave reception only. I tried it on the PL-990. Works great.

The AN-200 and the PL-990

It is hard to tell which one, the PL-LA400 or the AN-200, fares better, as the signal strength and S/M readings are quite close. They both perform better than the radio’s internal ferrite bar antenna to varying degrees, by improving the signal strength or the S/N ratio or both. The Tecsun loop is a passive antenna, meaning no power is required, making it easy to be used “wirelessly”, by simply placing the loop close to the radio, without having to be connected to the radio via a cable.

Chocolate, our house cat, tries to enhance reception with her tail

It should be noted that in the “wireless” mode of the AN-200 the antenna switch on the PL-990 should remain at “Int” so as for its built-in ferrite bar and the loop to couple with each other.

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