Tag Archives: Guy Atkins

Upgrade the encoder on your Xiegu G90 for about $8.00 US

Shortly after posting some of my initial impressions of the Xiegu G90, SWLing Post contributor, Guy Atkins, encouraged me to upgrade the stock G90 tuning knob/encoder with one that is highly recommended by the G90 community.

While I didn’t really have an issue with the stock plastic knob, I couldn’t resist a larger, slightly heavier aluminium encoder with a dimple.

The stock G90 encoder knob (before pic)

I’m so happy I splurged for this $8 upgrade. Not only is the encoder much easier to use now, but it also gives the G90 a proper face-lift:

The upgraded aluminium G90 encoder knob (after pic)

Thanks so much for the tip, Guy! I, too, highly recommend this affordable upgrade!

Get your upgraded encoder knob from:

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The AirSpy HF+ Discovery and a new era of portable SDR DXing

The following article first appeared in the January 2020 issue of The Spectrum Monitor magazine.


The AirSpy HF+ Discovery and a new era of portable DXing

I admit it: I used to be a bit of an old-fashioned radio curmudgeon. One of those, “I like my radios with knobs and buttons” likely followed by, “…and no other way!”

However, about fifteen years ago, many of my DXing friends started turning to the world of software defined radios (or in common parlance, “SDRs”). I staunchly opposed ever following in their footsteps. One of the reasons I for this––a good one––is that, since I spend the bulk of my day in front of a computer, why would I ever want to use a computer when I’m playing radio?

But then…gradually, I found myself playing around with a few SDRs. And I quickly learned that third-generation SDRs were capable of doing something very impressive (and fun), indeed:  making spectrum recordings.  Using this tool, I found I could record not only the audio of one individual signal, but the audio of entire swathes of radio spectrum.  And even more impressive, I learned that you could later load or “play back” the spectrum recording and tune through the bands as if in real time. Any time you want. Before long, I was hooked: SDRs had become my portal into radio time travel!

I quickly found that I loved many of the other advantages of using an SDR, as well, including visual ones––like the ability to view spectrum. The interactive interface allows one to actually see radio signals across the band in real time. I also found incredible value in waterfall displays, which show signals changing in amplitude and frequency over time. Cool stuff.

I purchased my first dedicated SDR in 2012, a WinRadio Excalibur. It was––and still is––a benchmark receiver, performing circles around my tabletop receivers and general coverage transceivers.

And today, although I own and love a number of legacy radios and still listen to them in the good old-fashioned manner to which I became accustomed, I find I’m now spending the bulk of my time DXing with SDRs.

And then, more recently, two amazing things happened in the world of SDRs. Strong market competition, together with serious innovations, have come into play. Thus, for less than $200 US, you can now purchase an SDR that would have easily cost $1,000 US only ten years ago. And now, in many cases, the $200 SDR of today will outperform the $1,000 SDR of yesteryear. We are, indeed, living in good times.

And now––no more a radio curmudgeon––I’m comfortable with my SDR-user status and time at the computer, and glad I was just curious enough about SDRs to let them into my radio (and computer) world.

Portable SDRs

Since I initially dived into the world of SDRs, I’ve tried to think of a way to take them into the field.

But first, let’s get an obvious question out of the way:

Why would you want to drag an SDR into the field, when a traditional battery-powered radio is so much easier to manage?

After all, you may say, portable and even mobile tabletop receivers require no computer, no hard drive, and are likely more reliable because there are less components to manage or to cause problems for you.

In answer, let’s look at a few scenarios where heading to the field with an SDR system might just make sense.  (Hint: Many of these reasons are rooted in the SDR’s ability to record spectrum).

Good Reason #1:  Your home location is not ideal for playing radio.

Photo by Henry Be

My good friend, London Shortwave, lives in the middle of London, England. He’s an avid radio enthusiast and DXer, but his apartment is almost a perfect storm of radio interference. Listening from his home is challenging, to say the least: he can only use indoor antennas and RFI/QRM simply inundated his local airwaves.

Many years ago, he discovered that the best way to DX was to go to an area that put urban noise and radio interference at a distance.  He found that by visiting large local parks, he could play radio with almost no RFI.

Being a computer guru, he started working on a portable SDR setup so that he could go to a park, set up an antenna, and record radio spectrum while he read a book.  His systems evolved with time, each iteration being more compact less conspicuous that the previous. Later, he could head back home, open the recorded spectrum files, and tune through these “time-shifted” recordings in the comfort of his flat. This allowed London Shortwave to maximize the low-RFI listening experience by reliving the time in the park.

Over the years, he tweaked and adapted his setup, often writing his own code to make small tablets and portable computers purpose-built portable-spectrum-capture devices. If you’re curious, you might like to read about the evolution of his systems on his blog.

Clearly, for London Shortwave, an SDR is the right way to capture spectrum and thus likely the best solution for his DX listening.

Good Reason #2:  Weak-signal workarounds.

Typically radio enthusiasts turn to field operation to work in a lower-noise environment and/or where there are no antenna restrictions, often to log new stations and DX.

SDRs afford the DXer top-shelf tools for digging weak signals out of the muck. SDR applications have advanced tools for tweaking AGC settings, synchronous detectors, filters, noise reduction, and even to tailor audio.

The WinRadio Excalibur application even includes a waterfall display which represents the entire HF band (selectable 30 MHz or 50 MHz in width)

On top of that, being able to see a swath of spectrum and waterfall gives one an easier way––a visual way––to pinpoint weak or intermittent signals. This is much harder to do with a legacy radio.

Case in point:  I like listening to pirate radio stations on shortwave. With a spectrum display, I can see when a new station may be tuning up on the band so can position the receiver to listen in from the beginning of the broadcast, and never miss a beat.

Or, in another example, the visual aspect of spectrum display means I can easily locate trans-Atlantic DX on the mediumwave bands by looking for carrier peaks on the spectrum display outside the standard North American 10 kHz spacing. The signals are very easy to spot.

Good Reason #3: DXpeditions both small and large.

Mark Fahey, scanning the bands with his WinRadio Excalibur/Surface Pro 2 combo at our 2015 PARI DXpedition

Whether you’re joining an organized DXpedition or you’re simply enjoying a little vacation DXpedition, SDRs allow you to make the most of your radio time.

Indeed, most of the organized DXpedition these days heavily incorporate the use of SDRs specifically so DXers can record spectrum. Much like example #1 above, doing this allows you to enjoy the noise-free optimal conditions over and over again through spectrum recordings. Most DXpeditioners will have an SDR making recordings while they use another receiver to DX in real time. Later, they take the recording home and dig even more weak signals out of the mix: ones that might have otherwise gone unnoticed.

Good Reason #4: Sharing the spectrum with like-minded listeners.

Earlier this year, Mark gave me this 8TB hard drive chock-full of spectrum recordings.

One of the joys I’ve discovered  in making field spectrum recordings is sharing them with fellow DXers. Most of the time when I go to shortwave radio gatherings (like the Winter SWL Fest), I take a couple hard drives to exchange with other SDR enthusiasts. My friend, Mark Fahey, and I have exchanged some of our favorite spectrum recordings this way. I give him a hard drive chock-full of terabytes of recordings, and he reciprocates. Back home (or on the train or airplane) I open one of his recordings and, boom! there I am in his shack in Freeman’s Reach, Australia, tuning through Pacific stations that are not easily heard here in North America, maybe even turning up some gems Mark himself may have overlooked…just as he is doing with my recordings from the southeast US.

I’ve also acquired DXpedition spectrum recordings this way. It’s great fun to “be there” through the recordings and to enjoy some of the benefits of being on the DXpedition in times when I couldn’t actually make it there in person. For a DXer with a consuming job, busy family life, or maybe health problems that limit their travel, an SDR recording is the way to go.

Good Reason #5: Family time

Photo by David Straight

I’m a husband and father, and no matter how much I like to play radio when we’re on vacation, my family comes first, and our family activities take priority.

Having a field-portable SDR setup means that I can arrange a “set it and forget it” spectrum capture device. Before we head out the door for a family visit, tour of the area, or a hike, I simply set my SDR to record spectrum, then listen to what I “caught” after I return, or after I’m home from vacation.

This practice has allowed me to enjoy radio as much as I like, without interrupting our family adventures. Can’t beat it!

Past challenges

With all of these benefits, one might wonder why many other DXers  haven’t been using portable SDRs in the field for a while now? That’s a good question.

Power

The WinRadio G31DDC, like many SDRs of the era, has separate data and power ports

In prior years, DXers and listeners might have been reluctant to lug an SDR and its requisite apparatus out with them. After all, it’s only been in the past decade or so that SDRs haven’t required a separate custom power supply; some legacy SDRs either required an odd voltage, or as with my WinRadio Excalibur, have very tight voltage tolerances.

Originally, taking an SDR to the field––especially in places without grid mains power––usually meant you also had to take a pricey pure sine wave inverter as well as a battery with enough capacity to run the SDR for hours on end.

Having spent many months in an off-grid cabin on the east coast of Prince Edward Island, Canada, I can confidently say it’s an ideal spot for DXing: I can erect large wire antennas there, it’s on salt water, and there are literally no locally-generated man-man noises to spoil my fun.  Of course, anytime we go to the cottage, I record spectrum, too, as this is truly a honey of a listening spot.

The view from our off-grid cabin on PEI.

The first year I took an SDR to the cabin, I made a newbie mistake:  it never dawned on me until I arrived and began to put it to use that my Goal Zero portable battery pack didn’t have a pure sine wave inverter; rather, I found it had a modified sine wave inverter built into it. The inverter could easily power my SDR, sure, but it also injected incredibly strong, unavoidable broadband noise into the mix. It rendered my whole setup absolutely useless. I gave up on the SDR on that trip.

Both the Airspy HF+ (top) and FDM-S2 (bottom) use a USB connection for both data transfer and power. Photo by Guy Atkins.

Today, most SDRs actually derive their power from a computer or laptop through a USB cable, one that doubles as a data and power cable. This effectively eliminates the need for a separate power system and inverter.

Of course, your laptop or tablet will need a means of recharging in the field because the attached SDR will drain its battery a little faster. Nowadays it’s possible to find any number of portable power packs/banks and/or DC battery sources to power laptops or tablets, as long as one is cautious that the system doesn’t inject noise. This still requires a little trial and error, but it’s much easier to remedy than having two separate power sources.

Portable computers

Even a Raspberry Pi 3B has enough horsepower to run SDR applications.

An SDR is nothing without a software application to run it. These applications, of course, require some type of computer.

I the past, SDR applications needed some computing horsepower, not necessarily to run the application itself, but to make spectrum recordings.  In addition, they often required extra on-board storage space to make these recordings sufficiently long to be useful.  This almost always meant lugging a full-sized laptop to the field, or else investing in a very pricey tablet with a hefty amount of internal storage to take along.

Today we’re fortunate to have a number of more portable computing devices to run SDR applications in the field: not just laptops or tablets, but mobile phones and even mini computers, like the eminently affordable $46 Raspberry Pi. While you still have to be conscious of your device’s computing horsepower, many small devices are amply equipped to do the job.

Storage

64-128 GB USB flash/thumb drives are affordable, portable storage options.

If you’re making spectrum and audio recordings in the field, you’ll need to store them somehow. Wideband spectrum recordings can use upwards of 2GB of data per minute or two.

Fortunately, even a 64GB USB flash drive can be purchased for as little as $7-10 US. This makes for quick off-loading of spectrum recordings from a device’s internal memory.

My portable SDR setup

It wasn’t until this year that all of the pieces finally came together for me so that I could enjoy a capable (and affordable!) field-portable SDR setup. Two components, in particular, made my setup a reality overnight; here’s what made the difference.

The AirSpy HF+ Discovery

Last year, AirSpy sent me a sample of their new HF+ Discovery SDR to test and evaluate. To be fully transparent, this was at no cost to me.

I set about putting the HF+ Discovery through its paces. Very soon, I reached a conclusion:  the HF+ Discovery is simply one of the best mediumwave and HF SDRs I’ve ever tested. Certainly, it’s the new benchmark for sub-$500 SDRs.

In fact, I was blown away. The diminutive HF+ Discovery even gives some of my other benchmark SDRs a proper run for their money. Performance is DX-grade and uncompromising, sporting impressive dynamic range and superb sensitivity and selectivity. The noise floor is also incredibly low. And I still can’t wrap my mind around the fact that you can purchase this SDR for just $169 US.

The HF+ Discovery compared in size to a DVD

In terms of portability, it’s in a class of its own. It’s tiny and incredibly lightweight. I evaluate and review SDRs all the time, but I’ve never known one that offers this performance in such a tiny package.

Are there any downsides to the HF+ Discovery? The only one I see––and it’s intentional––is that it has a smaller working bandwidth than many other similar SDRs at 768 kHz (although only recently, Airspy announced a firmware update that will increase bandwidth). Keep in mind, however, that the HF+ series SDRs were designed to prevent overload when in the presence of strong local signals. In fairness, that’s a compromise I’ll happily make.

Indeed, the HF+ Discovery maximum bandwidth isn’t a negative in my estimation unless I’m trying to grab the entire mediumwave band, all at once. For shortwave work, it’s fine because it can typically cover an entire broadcast band, allowing me to make useful spectrum recordings.

The HF+ Discovery is so remarkably tiny, that this little SDR, together with a passive loop antenna, can fit in one small travel pouch. Ideal.

The antennas

My homebrew NCPL antenna

Speaking of antennas, one of the primary reasons I’m evaluating the HF+ Discovery is because it has a very high dynamic range and can take advantage of simple antennas, in the form of passive wideband magnetic loop antennas, to achieve serious DX.

AirSpy president and engineer, Youssef Touil, experimented with several passive loop antenna designs and sizes until he found a few combinations ideally matched with the HF+ Discovery.

My good buddy, Vlado (N3CZ) helped me build such an antenna per Youssef’s specifications. Vlado had a length of Wireman Flexi 4XL that was ideal for this project (thanks, Vlad!). The only tricky part was penetrating the shielding and dielectric core at the bottom of the loop, then tapping into both sides of the center conductor for the balun connections.  Being Vlado, he used several lengths of heat shrink tubing to make a nice, clean, snag-free design. I’ll freely admit that, had I constructed this on my own, it wouldn’t have been nearly as elegant!

Click here for a step-by-step guide to building your own NCPL (Noise-Cancelling Passive Loop Antenna.

Youssef also sent me a (then) prototype Youloop passive loop antenna. It’s incredibly compact, made of high quality SMA-fitted coaxial cables. It can be set up in about 30 seconds and coiled to tuck into a jacket pocket.  The AirSpy-built loop has a lower loss transformer than the one in the homemade loop, which translates into a lower noise figure for the system.

Click here to read my review of the Youloop.

Let’s face it: SDR kit simply doesn’t get more portable than this.

The computer

My Microsoft Surface Go tablet on a hotel bed.

In the past, I used an inexpensive, circa 2013 mini Windows laptop with an internal SSD drive.  Everything worked beautifully, save the fact that it was challenging to power in the field and the internal capacity of the hard drive was so small (16GB less the operating system). In addition, it was a few years old, bought used, so the processor speed was quite slow.

This year, on the way back from the Huntsville Hamfest, I stopped by the Unclaimed Baggage Center in Scottsboro, Alabama. This center has a wide variety of used portable electronics at discount prices. I felt pretty lucky when I discovered a like-new condition Microsoft Surface Go tablet and keyboard with original charger for $190. The catch? The only data port on the tablet is a USB-C. But I grabbed a small USB-C to standard USB 3.0 dongle (for $2!) and took a risk that it would work with the HF+ Discovery.

Fortunately, it did! Score!

While the Surface Go is no powerhouse, it’s fast enough to run any of my SDRs and make spectrum recordings up to 2 MHz in width without stuttering. The only noise it seems to inject into the mix is a little RFI when I touch the trackpad on the attached keyboard.

Power

One of my LiFePo batteries

The HF+ Discovery draws power from the Surface Go tablet via the USB port. With no additional power supply, the Surface Go may only power the HF+ Discovery for perhaps an hour at most. Since I like doing fully off-grid operations and needed to avoid RFI from inverters, I needed a portable power solution.

Fortunately, the Surface Go has a dedicated power port, so I immediately ordered a DC power cable with a standard car lighter plug.

At the Huntsville Hamfest I also purchased a small 12V 4.5 Ah Bioenno LiFePo battery and paired it with a compact Powerpole distribution panel kit I purchased in May at the 2019 Dayton Hamvention.

The LiFePo battery is small, lightweight, and can power the tablet /SDR combo for hours on end. Moreover, I have noticed no extra noise injected when the DC power is applied.

My HF+ Discovery-based portable SDR kit

My portable SDR kit on a hotel balcony.

Now I have this kit, I couldn’t be more pleased with it. When all of the components of my SDR system are assembled, they work harmoniously. The entire ensemble is also incredibly compact:  the loop antennas, SDR, Surface Go tablet, battery, and distribution panel all fit in a very small travel pack, perfect for the grab-and-go DX adventure.

The entire kit: SDR, cables, Youloop antenna, connectors and adapters all fit in my Red Oxx Lil’ Roy pack.

In November, I took the kit to the coast of South Carolina and had a blast doing a little mediumwave DXing from our hotel balcony. We were very fortunate in that I had two excellent spots to hang the homemade loop antenna: on the main balcony, and from the mini balcony off the master bedroom. Both spots yielded excellent results.

What impressed me most was the fact that the SDR# spectrum display and waterfall were absolutely chock-full of signals, and there was very little noise, even in the popular resort area where we were staying. I found that my portable radios struggled with some of the RFI emanating from the hotel, but the HF+ Discovery and passive loop combo did a much better job mitigating noise.

Check out the AM broadcast band on the spectrum display.

But no need to take my word for it.  If you would like to experience it first hand, why not download an actual spectrum recording I made using this setup?

All you’ll need to do is:

  1. Download the 1.7 GB (.wav formatted) spectrum file at this address
  2. Download a copy of SDR# if you don’t already have an SDR application that can read AirSpy spectrum files.
  3. Install SDR#, and run it.
  4. At the top left corner of the SDR# screen, choose “IQ File (.wav)” as the source, then point it to where you downloaded the file.
  5. Press the play button, and experience a little radio time travel!

This particular recording was made on the mediumwave band on November 17, 2019, starting at around 01:55 UTC.

My portable SDR kit capturing spectrum during a hike in Pisgah National Forest.

I’ve also taken this setup to several parks and remote outdoor locations, and truly enjoyed the freedom of taking spectrum recordings back home to dig through the signals.

Conclusion

I finally have a portable SDR system that allows me the flexibility to make spectrum recordings while travelling. The whole setup is compact and can easily be taken in a carry-on bag when flying.

The glory of this is, I can tune through my spectrum recordings in real time and DX when I’m back home, or even on the way back home, in the car, train, or airplane. It’s simply brilliant.

If you don’t already own an SDR, I can highly recommend the AirSpy HF+ Discovery if you’re primarily interested in HF and MW DXing. If you need a wideband SDR, I could also recommend the recently released SDRplay RSPdx, although it’s slightly heavier and larger than the AirSpy.

Thankfully, I am now an SDR enthusiast that can operate in the field, and this radio has had a lot to do with it. I’ll be logging many hours and miles with the AirSpy HF+ Discovery: its incredibly compact footprint, combined with its brilliant performance, is truly a winning combo.

Click here to check out the Airspy HF+ Discovery

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More info about Eneloops and avoiding counterfeits

Following our post yesterday regarding Eneloop rechargeable cells, SWLing Post contribtors Guy Atkins and Ivan Cholakov both warned of numerous fake and counterfeit batteries available from sellers on eBay and elsewhere. Ivan notes:

Please be aware Eneloop batteries are widely copied and there are many many fakes out there. You should only buy them from a reputable source.

Thank you for that warning, Ivan!

Guy also comments:

I use Eneloop Pro AA batteries in small portables. The newest version of the “Pro” comes in a 2500 maH size and retains 85% of the charge for one year. The downsize is that this model is “only” good for 500 recharges. A useful comparison chart is here: https://en.wikipedia.org/wiki/Eneloop

[…]Here is a FAR more comprehensive page of Eneloop model & version comparisons, charts, FAQs, tips, warnings, etc.: https://eneloop101.com/batteries/complete-lineup/. This web site also contains warnings about Ebay fake Eneloops, and other useful details…probably more than most people want to know but if you want to make the most informed choice, check it out!

Many thanks to both of you for sharing. I agree that purchasing Eneloops from a reputable seller is incredibly important. For one thing, if you plan to invest in Eneloops, there is no rationale to buy something sub-standard. Additionally, I do worry about counterfeit cells having an unstable chemistry which could result in overheating or fire.

Click here to read our original Eneloop article with links to reputable sellers.

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SDR Console Version 3: A Holy Grail SDR application for the radio archivist

Encouraged by SWLing Post contributors Guy Atkins and Ivan Cholakov, I recently installed the latest version of SDR Console on my PC.

I had not tried SDR Console in many, many years, but after Guy announced that SDR Console had moved from preview to Beta, I decided it was time to try it once again.

All I can say is: WOW!

As someone who evaluates a number of software defined receivers and who regularly makes off-air audio and spectrum recordings, I’m simply amazed by SDR Console’s versatility.

The recording functionality, as Guy previously stated, is phenomenal–perhaps the best of any SDR application I’ve used to date save, perhaps, that of the Titan SDR Pro (which is proprietary).

Though I still haven’t logged a lot of hours on SDR Console, I can already mention several powerful features that I love:

Virtual receivers

So few SDR applications allow you to run multiple virtual receivers and–especially–make independent recordings from them simultaneously.

When I started writing this post last night, I was listening to and recording the Voice of Greece on virtual receiver #1,  Radio Guinea on #2, and WRMI on #3 using the brilliant little AirSpy HF+.

Audio recording options

When you start a recording of an active virtual receiver, a dialog box pops up allowing you to make a custom file title–it pre-populates the date, start time, frequency and mode. This is a simple but time-saving feature as most SDR applications save files according to global application settings–not for each individual recording. With the SDR Console dialog box, I can insert the name of the broadcaster in the file title which makes organizing recordings later a breeze.

Additionally, you can choose between MP3, WAV or WMA file types for each recording. I know of no other SDR app that gives you this flexibility.

Scheduled recordings

I’ve yet to use the scheduler feature, but based on Guy Atkins’ feedback, I know this will be an invaluable resource for collecting off-air recordings while I’m away from home.

So many features to discover…

As both Guy and Ivan have shown us in past posts, SDR Console allows for multiple application “instances”–meaning, you can run two independent SDRs simultaneously. This is a fantastic feature for those of us who make multiple spectrum recordings. Of course, it’s an ideal platform to compare SDR hardware as settings can be easily matched between both units (something very difficult to do when using different SDR applications).

I’ve so much to learn about SDR Console, but I can tell I’ll be spending a great deal of time with the application this year, attempting to learn every nuance.

I took Guy Atkins’ suggestion for new users of SDR Console and downloaded Paul Jones’ (NN4F) PDF manual.

I sent a donation to Simon (G4ELI) last night after having only used SDR Console for a few minutes. SDR Console is totally free, but I’m a firm believer in supporting creators who are doing amazing things! If you use SDR Console, consider sending Simon a donation as well.

I’ve a little free time this morning and plan to set up SDR Console to run my Elad FDM-S2, RTL-SDR dongle, SDR Play RSP1A and RSP2. It’ll be a bit revolutionary to have one SDR application to unite them all!

Post readers: Any other SDR Console fans out there?  What are your favorite features?

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An EDC Bag for the Classic Sony ICF-SW100 Receiver

In a 2014 article, this site’s administrator Thomas Witherspoon introduced readers to the CIA’s Survival Kit which is housed in a superbly sturdy waistpack, the Maxpedition M-2. Thomas observed that the M-2 pouch is perfectly suited to holding the diminutive Sony ICF-SW100 receiver.

I was intrigued by that possibility, but only recently tried to combine the two after I resurrected another ICF-SW100 that fell silent to the chronic broken ribbon cable problem. Indeed, the radio is a perfect fit and the M-2 is impressively solid and well designed. I was not aware of the Maxpedition firm prior to learning of the M-2 bag, but I see in various forums they are a major player in well-made gear for the survivalist and outdoor enthusiast crowds. The M-2 is a very popular item, and one or more of the four available colors are sometimes out of stock at the manufacturer. Fortunately there are many sellers on Amazon and Ebay who have these waistpacks available.

What is EDC you may ask? It refers to “Every Day Carry”, the essentials that an individual deems necessary for their lifestyle or a particular activity. For me, an EDC bag is taken along on hikes or other outings to the countryside and typically contains a compact shortwave radio and related accessories. It’s always fun to stop for lunch or a break in a remote location and be able to search for interesting stations whenever the mood strikes.

This photo shows what I’m able to carry in the Maxpedition M-2 bag; a coffee mug is shown for size comparison. Contents of the “kit” include:

  • The Sony ICF-SW100 receiver
  • Zero Audio Carbo Tenore In-Ear Monitors & soft pouch
  • Sony AN-71 reel-up antenna
  • Panasonic RR-XS400 Digital Voice Recorder
  • Short 3.5mm male-to-male stereo audio patch cable
  • Two extra AA batteries for the Sony receiver
  • An extra AAA battery for the Panasonic Digital Voice Recorder

A few comments on the contents. The Zero Audio Carbo Tenore In-Ear Monitors (IEMs) provide excellent audio quality for their price. They are among a handful of IEMs regularly recommended by budget-minded audiophiles on the popular Head-fi.org site. I like these IEMs not only for the audio quality, but also their small size (in the cloth bag) which barely fits into the M-2’s main compartment along with the ICF-SW100. Larger earbuds or IEMs might not fit the M-2 without being mangled by the hefty YKK zippers. One caution: the similar Carbo Basso model by Zero Audio is deemed by many to be overly heavy on the bass frequencies. I find the Carbo Tenore to be more than sufficient for bass heavy genres like Electronica.

The Panasonic RR-XS400 digital voice recorder has been out of production a few years, but is a highly capable and compact recorder. It contains a hidden USB plug for charging and data transfer, has a fully featured and backlit LCD display, built-in stereo microphones, switchable LINE/MIC inputs, and other useful features. In excellent used condition the RR-XS400 is worth about $50 USD in 2017, despite some Amazon sellers trying to move them at the original $280 price.

The extra AAA battery for the recorder slips into the front pouch of the M-2 bag along with the Sony AN-71 antenna. The additional AA batteries for the radio, however, are held in the two “pen loops” on the left and right of the M-2. Despite these loops being open-bottomed tubes, the fit is tight enough to hold the batteries securely.

Like every portion of the Maxpedition M-2 bag, the belt loop is proportioned perfectly and sewn with precision. With the Sony ICF-SW100 EDC “kit” secured to my belt on a hike, I’m assured of quick access to a DXing opportunity, such as when hiking the Naches Loop Trail near beautiful Mt. Rainier:

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

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A New Approach to FSL Antenna Construction

Introduction

I’m very fortunate to live across town from my good radio hobby pal Gary DeBock. He has been responsible for the rapid growth in Ultralight radio DXing and the construction of Ferrite Sleeve Loop (FSL) antennas. Living near each other as we do, I’ve benefited a lot from his expertise and creativity in the hobby. We’ve enjoyed visiting about Ultralight radios and antennas many times over a leisurely lunch. If you’re unfamiliar with Gary’s efforts, just do a YouTube search on his name and see just a few of the many FSL antenna variations he’s built!

Gary uses PVC tubing, “Fun Noodle” foam cylinders, sections of curved foam, and rubber plumbing adapters almost exclusively as the core supporting structures for his FSLs, from small 3-inch models to 17-inch monsters. Gary certainly has perfected his own techniques with these raw materials; he’s an expert in combining them. He even makes PVC table structures to support his FSLs during Oregon coastal DXpeditions, as seen in some of his YouTube videos.

These materials work well, but over time even FSLs as small as 7 to 8 inches in diameter begin to sag and lose their perfectly circular shape. This seems to be caused by the shifting of individual segments of foam which are wrapped around a “Fun Noodle” core and center PVC tubing.

What possibilities are there for other materials in FSL antenna construction? It would be a fun challenge to build a small to medium sized FSL antenna that would have these qualities:

  • Maintain a circular cross-section without sagging
  • An appearance less like a threatening explosive and more like a commercial product
  • Use alternate construction methods for those not skilled with cutting & gluing PVC tubing

I began to keep my eyes open for likely candidates as I visited hardware stores, department stores, and office supply outlets. Eventually some ideas began to gel.

Raw Materials

Here is a visual and descriptive list of what I used in this alternate design of Ferrite Sleeve Loop antenna. I won’t go into great detail about dimensions, quantities, and measurements, as other DIYers should be able to easily follow the general idea presented here. This article is mainly to get you thinking about other ways to construct a ferrite sleeve loop antenna.

The Core of the Matter

This 18-inch long, semi-rigid foam roller is six inches in diameter. It’s a workout and exercise aid which I found in the sports department of my local Walmart store. The cost was approximately $13. This one-piece foam is a perfect foundation for holding and protecting the fragile ferrite rods and keeping them in a circular arrangement; since the roller is in one piece there is nothing to shift around, or sag. When placed on this core, the final diameter of the FSL antenna is approximately seven inches.

So, what to put the antenna in? Something needs to suspend and protect the antenna as a substitute for the PVC frame previously used. This Sterilite tote box is the perfect size to hold the antenna. As shown in the photo, the dimensions are approximately 14-1/4″ X 9-5/8″ X 12-1/4″; the model number is 1896.

Early on, I decided that the flimsy “locking tabs” on the cover would not suffice for holding the relatively heavy antenna when carrying the tote by the handle. I drilled holes and attached a dozen small Nylon nuts and bolts to secure the cover. (Nylon avoids distorting the medium wave reception pattern of signals, as metal hardware could.)

An ample quantity of 200mm ferrite rods are needed, plus a air variable capacitor (preferably with a 8:1 reduction drive shaft), and Litz wire. 1162 strands/46 ga. Litz provides the most sensitivity but the coil will cover a greater width on the rods.

Gary likes to use waterproof medical tape, sticky side out, to hold the rods in place, but I like to use Gorilla brand tape, as it is extremely sticky and holds the rods better. My choice for the rod-to-coil spacing  material is two turns of 1/8″ thick bubble wrap.

This is the foam core, ferrite rods, bubble spacer, and coil assembly prior to fitting in the Sterilite tote container. Before assembly to this point you’ll need to cut the foam roller to length using a serrated knife or electric carving knife. Two sturdy cable ties help hold all of the rods in place. A better alternative might be strips of 1/2″ wide Velcro straps purchased from a fabric shop or home improvement store.

Another key item to this construction method is the use of plastic drywall anchor screws. These are meant to be pushed and screwed into gypsum wallboard for sturdy attachment of bolts or picture hangers on walls. When screwed through drilled holes in the side of the Sterilite tote, they secure and suspend the foam roller/ferrite sleeve loop assembly. The density of the foam roller is sufficient to give a good grip to the drywall anchors. Eight to ten anchors per side are enough to hold the assembly in place. See the photo at the beginning of this article for a good view of this mounting method.

Every good FSL antenna design needs an official sounding manufacturer! With tongue firmly in cheek I’ve appropriated the name shown on this self-produced label. Clearly, a Ferrite Sleeve Loop antenna from Naughtabaum Ferrite Specialties Ltd. stands a better chance than most of passing through TSA checkpoints, right?

I hope this article has given you some new ideas for FSL antenna designs. There’s certainly room for improvement, including making the antenna’s ferrite rods look less intimidating…less like a bundle of dynamite! Perhaps the entire assembly can be wrapped with something that shields the rods from view, or you could use an opaque tote container rather than a clear model.

Be on the lookout for useful materials to repurpose. Trips to your local home improvement stores, office supply, and other outlets will give you further ideas on how to design your own Ferrite Sleeve Loop antenna.

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

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Rare Hitachi KW-WSI WorldSpace Receiver on Ebay

This is the first and only “WorldSpace” satellite receiver I’ve seen on Ebay, currently offered at a $175 Buy-It-Now price from a seller in Australia:

http://www.ebay.com/itm/HITACHI-KW-WSI-DIGITAL-RECEIVER-WS-FM-MW-SW1-SW2-/282192383263

The radio is listed as in excellent condition with the original box and literature. Besides the long-gone WorldSpace satellite frequencies, the radio covers medium wave, FM, and most of the shortwave range. A brief PDF data sheet for the radio gives a description of features and operations.

hitachi-kw-wsi

Wikipedia describes this radio’s satellite service as 1worldspace, formerly known as ‘WorldSpace’, is a defunct satellite radio network that in its heyday provided service to over 170,000 subscribers in eastern and southern Africa, the Middle East, and much of Asia with 96% coming from India. It was profitable in India, with 450,000 subscribers.

I wonder if the Hitachi KW-WSI is a reasonable performer for shortwave listening? Does anyone know any technical details of this receiver?

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

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