Author Archives: Thomas

Form follows function in the Tom Bihn Travel Tray

If you’ve been reading the SWLing Post for long, you no doubt know that not only am I radio geek, but a pack geek as well.

In a typical year––although, admittedly, this is not one––I do quite a bit of regional travel. I’m an minimalist traveler when I’m on the road, eschewing lots of unnecessary stuff, but I do still carry quite a bit of kit that’s important to me…in the form of radio gear.

Several years ago, I discovered Washington state pack designer and builder, Tom Bihn. Like Red Oxx (another favorite), Tom Bihn manufactures everything in their US factory, treats their employees like gold, and guarantees their gear for life. Breath of fresh air.

Yes, since it’s made on US soil, Tom Bihn gear can be pricey. But, hey, since it’s with you for life, I feel it’s worth the splurge.

I now own numerous Tom Bihn packs, bags, and accessories. But they make one product I use more than any other: the Travel Tray.

The Travel Tray (and don’t be fooled by the name; it’s definitely not for serving tea on a train) is an ingenious travel accessory––more of a pouch, really––that comes in two sizes: small ($22) and large ($25). I find the large size to be ideal.

So, what is it used for––? Let’s start with TB’s description:

Pop the Travel Tray out of your luggage when you arrive at your destination and drop in your keys, coins, wallet, cell phone — all that small stuff you don’t want to have wander off while you sleep.

Think of it as a babysitter for the miscellanea that ends up in your pockets: our Travel Tray keeps an eye on all that until you’re ready to face the world again. Unlike other travel trays, ours pulls shut with a drawstring so it can be used for more than just organizing the top of your bureau.

Need to depart with some degree of alacrity? Simply leave some or all of those little things in the tray, pull the drawstring, and hit the road.

The Travel Tray packs flat–in my GoRuck GR1 backpack, I store it in the inside front panel mesh pocket.

When I arrive at a hotel, B&B, AirBnB, or at a home I’m visiting, the first thing I do is pull the flattened travel tray out of my pack, pop it up (yep, it’s conveniently self-supporting), and throw in my keys, wallet, phone, earphones, passport, and everything else in my pockets. All kinds of little things land in there. If I pull something small from my pack, when not in use, it goes in the travel tray. This way, I’m way less likely to leave a small item in the hotel when I leave.

If you’ve ever been to one of my presentations, you might have even see me use a Travel Tray at the podium to keep track of any items I’ve brought to show. I’ve always carried a Travel Tray in both my EDC pack and my travel backpack.

And you know what? Since I’ve been using Travel Trays, I haven’t left even one small item in a hotel room.

Great! But what does this Travel Tray have to do with radio––???

Not only can it hold a small radio or two…The large TB Travel Tray is ideal for something else:  antenna cables, power cables, and connectors!

In fact, I just discovered that it’s the perfect portable storage for my recently-reviewed Airspy Youloop antenna!

The Youloop rolls up for storage, and it just so happens the diameter of the Travel Tray is nearly identical to that of the poly bag in which the Youloop was shipped.

That little organizer pouch in the middle of the bag? It contains the Youloop cross-over box and tee, along with some small patch cables. Tom Bihn actually sent the small pouch free with my recent order of yet another Travel Tray––they’re currently including one with every order (details here). Sweet!

I could easily fit an SDR and all associated cables in this pack, too. In fact, as you can see, the antenna only takes up a small fraction of the tray’s capacity when it’s popped up.

With the Youloop and all accessories inside, the Travel Tray packs flat

When I’m ready to travel, I just pull the drawstring, and squash the Tray flat! Then I have only to toss it in my pack…couldn’t be easier.

During the Covid-19 pandemic, I’m doing what I can to support small businesses that are important to me, such as this small American company. I purchased the blue travel tray above because…well, you can never have too many, right?

If you’d like to check out the Tom Bihn Travel Tray, here’s a direct link to the product page on the TB website. Note that shipping times vary because the company is taking serious precautions, and also diverting much of their factory work to producing much-needed face masks right now. Go, Tom Bihn!

Again, I prefer the large Travel Tray, but they also make a handy small Travel Tray. These come in a number of other colors, but I go for the bright colors because they stand out, meaning a quick scan of that hotel room or wooded campsite will always reveal just where I left my gear. You can even choose your preferred fabric weight––”halcyon” fabric or a 210 ballistic. I prefer halcyon because it’s lighter weight, yet still incredibly durable (both trays seen above are made with halcyon).

Got this Tom Bihn pouch? What do you use yours for? Feel free to comment below!


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love

Radio Waves: The Future of On-Air DJs, SDR Comparison, Radios That Never Were, and an Internet Radio Player for Linux

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Jack Kratoville, Dave Zantow, and Dennis Dura for the following tips:


Live From Everywhere? The American Radio DJ In An On-Demand World (1A)

iHeartMedia owns and operates 858 broadcast radio stations, serving more than 150 markets throughout the U.S. The company reaches over a quarter billion monthly listeners ?in America.

In January, news hit that iHeartMedia was reassessing its ability to adapt to the modern music industry. The company said that it plans to make “significant investments … in technology and artificial intelligence.”

However, its on-air DJs were caught off guard when they found out that the company’s restructuring plan didn’t include them.

Streaming platforms has ushered in the digital age of music where each person make their own playlists. What does that mean for the future of the on-air DJ in the United States?

Click here to listen to the audio.

A comprehensive lab comparison between multiple software defined radios (RTL-SDR.com)

Librespace, who are the people behind the open hardware/source SatNOGS satellite ground station project have recently released a comprehensive paper (pdf) that compares multiple software defined radios available on the market in a realistic laboratory based signal environment. The testing was performed by Alexandru Csete (@csete) who is the programmer behind GQRX and Gpredict and Sheila Christiansen (@astro_sheila) who is a Space Systems Engineer at Alexandru’s company AC Satcom. Their goal was to evaluate multiple SDRs for use in SatNOGS ground stations and other satellite receiving applications.

The SDRs tested include the RTL-SDR Blog V3, Airspy Mini, SDRplay RSPduo, LimeSDR Mini, BladeRF 2.0 Micro, Ettus USRP B210 and the PlutoSDR. In their tests they measure the noise figure, dynamic range, RX/TX spectral purity, TX power output and transmitter modulation error ratio of each SDR in various satellite bands from VHF to C-band.

The paper is an excellent read, however the results are summarized below. In terms of noise figure, the SDRplay RSPduo with it’s built in LNA performed the best, with all other SDRs apart from the LimeSDR being similar. The LimeSDR had the worst noise figure by a large margin.[]

Radios that Never Were (N9EWO)

Dave Zantow (N9EWO) shares a new page on his website devoted to receivers and amateur transceivers that never quite made it to the marketplace. []

Shortwave: A Modern Internet Radio Player for Linux (It’s Floss)

Brief: Shortwave is a modern looking open source Internet Radio player for Linux desktop. We take a quick look at it after its recent stable release.

Shortwave is an interesting open-source radio player that offers a good-looking user interface along with a great experience listening to the Internet stations. It utilizes a community-powered database for the Internet stations it lists.

Shortwave is actually a successor of the popular radio app for Linux, Gradio. Its developer Felix joined GNOME and discontinued Gradio to create Shortwave from scratch in Rust programming language. If you were using Gradio as your preferred Internet radio station player, you can import the library as well.

Recently, Shortwave released its first stable version and seems to push new updates after that as well.[]


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love

The Airspy Youloop is a freaking brilliant passive loop antenna

Before I start talking Youloop, I have a little confession to make up front:

At the Winter SWL Fest when I gave a presentation about Portable SDR DXing, not only did I give attendees the wrong name of the Airspy Youloop antenna, but I also configured it incorrectly, hence the poor performance via my Miscrosoft Surface Go tablet PC.

I had assumed the the crossover component of the antenna was the transformer component. I realized the mistake I made when I saw some of the first promotional photos of the Youloop antenna a few weeks ago.

The crossover connects both sides of the loop while the tee junction contains the transformer.

Doh! I’m trying to forgive myself for making such an obvious mistake, but in my defence–and in the spirit of full disclosure–my antenna was a very early sample prototype without instructions, diagrams, etc. so I set it up imagining it being similar to the homebrew loop Vlado and I built. (FYI: When I say “Vlado and I built” it, I really mean, “Vlado built it.”) 

So obviously I made a poor assumption.

Once I assembled the antenna correctly? Wow. Just. Wow!

Youloop: The ideal travel antenna for high dynamic range SDRs

The Youloop, Airspy HF+ Discovery, SDRplay RSPdx, and all cables easily fit in my Red Oxx Lil Roy pack.

The Youloop is truly the travel antenna I’ve always wanted for portable SDR DXing. Here’s why:

  • It’s incredibly portable and can be rolled up to fit in a small travel pouch
  • It has all of the low-noise characteristics of other magnetic loop antennas
  • It’s wideband unlike many passive loop designs
  • It requires no variable capacitor or tuner
  • It’s made of quality components
  • It requires no external amplifier nor power source
  • It takes one minute to assemble
  • It’s affordable (~$35 USD shipped)

The only caveat? To take advantage of the Youloop, you must use a high dynamic range receiver.

Airspy HF+ Discovery SDR

I can verify that this antenna works brilliantly with the Airspy HF+ Discovery.

The AirSpy HF+ SDR

It will also pair well with the Airspy HF+  if you shortcut R3 via the R3 modification.

SDRplay RSPdx SDR

I’ve also used it numerous times with the new SDRplay RSPdx while using SDRuno in High Dynamic Range (HDR) mode. With the RSPdx, I can make spectrum recordings of the entire AM broadcast band. Note that HDR mode is only available on the RSPdx at 2 MHz and below, using the SDRuno app.

I have not tested the Youloop with other SDRs yet. I will soon test it with my WinRadio Excalibur.

So how well does the Youloop perform?

Listen for yourself!

I’m doing a little cargiving family members today. Their home is swimming in RFI (radio interference/noise). In the past, I’ve struggled to make good mediumwave recordings at their home–certainly an ideal situation for a mag loop antenna.

This morning, I wanted to record one of my favorite local AM stations (WAIZ at 630 kHz), so I set up the Youloop in the middle of a bedroom, hanging off a large bookshelf set against an interior wall. In other words: not an ideal situation.

When I plugged in the Airspy HF+ Discovery and loaded the Airspy SDR application, I fully expected to see a spectrum display full of broadband noise.

Instead, I saw signals. Lots of signals:

Sure, there’s some noise in there, but it’s low enough I could even do proper mediumwave DXing on most of the band if I wished.

In fact, if you’d like to experience the HF+ Discovery/Youloop pairing in this compromised, less-than-ideal DXing setup, why not tune through one of the spectrum recordings I made?

Click here to download the spectrum file [885.7MB .wav].

The recording was made on March 30, 2020 starting around 10:50 UTC. You’ll need to open this file in AirSpy’s free application SDR# or a third party SDR app that can read AirSpy .wav files.

I can’t wait to try the Youloop in other locations. Since we’re in lock-down due to Covid-19, I won’t be able to try the Youloop in a hotel any time soon. Almost all of my 2020 travel plans have been canceled.

Highly recommend

If you have one of the SDRs mentioned above, go grab a Youloop. At $35 USD, it’s a fantastic deal.

Click here to check out the YouLoop at the RTL-SDR.com store ($34.95 USD shipped).

Click here to check out the YouLoop at Airspy.US ($29.95 + shipping).

Click here to search for AirSpy distributors in your region/country.

If you don’t have a high dynamic range receiver, note that Airspy is exploring the idea of making a pre-amp for the Youloop. If interested, you might drop them a note of encouragement!

Do you have a Youloop? Please share your comments!


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love

“BBC to provide free DAB radios to over-70s”

(Source: IBC via Tony Robbins)

  • BBC Radio to provide free DAB radios to over-70s
  • Radios to be given away due to isolation caused by coronavirus
  • Broadcaster partners manufacturers, retailers and charity for giveaway

The broadcaster’s local radio unit will give away free DAB radio units to over-70s nominated by local listeners, as part of the BBC’s Make a Difference campaign.

The project is running across all 39 of the BBC’s local radio stations in England, with partners – including Argos, Currys PC World, John Lewis & Partners, Pure and Roberts Radio – setting aside thousands of radios to give away.

The radios will be distributed by loneliness charity Wavelength, while manufacturer Duracell has agreed to provide batteries for free for the radios.

Tony Hall, the outgoing director-general of the BBC, said: “Local radio is a lifeline at this time and has never been more important as a source of trusted local news and information, and also as a companion for people who are isolating.

”Make A Difference is already having a huge impact right across the country with 28,000 thousand calls in just five days. It is offering support and practical solutions to people who have nowhere else to turn.

“We want everyone who needs access to the radio to have it, that’s why we’re giving away DAB radios. I’m proud we’ve been able to coordinate this initiative with our partners who have been so generous in offering their resources.”[…]

Click here to read the full article.

Spread the radio love

Radio Waves: ACMA Report, Maine Stations Close, The National Emergency Library, and RAF Bombing Disrupted Propaganda

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’sRadio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Alan, Bill Mead, Bill Hemphill, and Gregg Freeby for the following tips:


The future delivery of radio (Australia Communications and Media Authority)

The ACMA released an issue paper in May 2019 to hear from industry about the delivery of radio.  We also wanted to consider if there needs to be any changes to support radio services into the future.

Following this, we conducted a public consultation, receiving submissions from across the industry. We found that live radio across different platforms is important to Australians. This is especially relevant during emergency situations, such as the recent bushfires. We also determined that a mix of platforms is crucial to bringing radio to listeners.

Our report identifies four broadcast spectrum planning priority activities to help support radio:

    • converting commercial, community and national radio broadcasting services from AM to FM where available
    • improving the coverage of radio broadcasting services where spectrum is readily available
    • making digital radio channel plans for regional DAB+ where there is a planned rollout
    • supporting trials of new broadcasting technology.

Report to the Minister Future delivery of radio (319.59 KB)

WOXO says farewell to listeners; Gleason Radio Group to go silent after 45 years (Sun Journal)

AUBURN — On Maine Big Z’s “The Breakfast Club,” Mark Turcotte interviewed local business owners, entertainers, activists, and once last summer, a mixed martial arts cage fighter and state senator one hour apart.

“Had to shift gears pretty quickly that morning,” quipped Turcotte, the morning show host since December 2018.

On Wednesday, he was abruptly down to two final shows.

Gleason Radio Group announced that its five stations will go off the air at 7 p.m. Sunday. They include Norway, Paris, Rumford, Mexico and Auburn.

“This feels like the end of an era in Maine radio,” Turcotte said.

Kathy Gleason has run the business with WOXO station manager Vic Hodgkins in the year since her husband, founder and former Auburn Mayor Dick Gleason, died.

“I feel that I tried very hard to keep it going and at the same time have it be for sale,” Gleason said. “It didn’t sell, it may sell. The coronavirus was kind of like the last straw as far as finances go.”

Hodgkins said a combination of low receivables and slow payments, combined with a projected drop in advertising because of COVID-19, has resulted in the need to close the stations.[]

Announcing The National Emergency Library (Internet Archive)

To address our unprecedented global and immediate need for access to reading and research materials, as of today, March 24, 2020, the Internet Archive will suspend waitlists for the 1.4 million (and growing) books in our lending library by creating a National Emergency Library to serve the nation’s displaced learners. This suspension will run through June 30, 2020, or the end of the US national emergency, whichever is later.

During the waitlist suspension, users will be able to borrow books from the National Emergency Library without joining a waitlist, ensuring that students will have access to assigned readings and library materials that the Internet Archive has digitized for the remainder of the US academic calendar, and that people who cannot physically access their local libraries because of closure or self-quarantine can continue to read and thrive during this time of crisis, keeping themselves and others safe.

This library brings together all the books from Phillips Academy Andover and Marygrove College, and much of Trent University’s collections, along with over a million other books donated from other libraries to readers worldwide that are locked out of their libraries.

This is a response to the scores of inquiries from educators about the capacity of our lending system and the scale needed to meet classroom demands because of the closures. Working with librarians in Boston area, led by Tom Blake of Boston Public Library, who gathered course reserves and reading lists from college and school libraries, we determined which of those books the Internet Archive had already digitized.  Through that work we quickly realized that our lending library wasn’t going to scale to meet the needs of a global community of displaced learners. To make a real difference for the nation and the world, we would have to take a bigger step.[]

World War II’s Strangest Bombing Mission (Air & Space)

The RAF knew how to cut the power on propaganda.

eichsmarschall Hermann Göring was beside himself with anger. Years before, he had told the people of Germany that no enemy aircraft would ever cross the country’s borders. Now, on January 30, 1943, a national day of celebration marking the 10th anniversary of Hitler’s rise to power, Göring was made to look like a buffoon.

Dodging in and out of slate gray clouds, Royal Air Force bombers from No. 105 Squadron howled across Berlin. With bomb doors open and Merlin engines at their limits, the wail from a trio of de Havilland Mosquitos mixed with blasts from anti-aircraft batteries below. If everything went as planned, all that noise was going to be on the radio.

In Berlin, amid the grim news from the battlefronts in North Africa and Stalingrad, the January 30 celebration was intended to take German minds off their fallen soldiers and reversals of fortune. The Nazis were going to have a parade. Göring, one of the most powerful figures in the National Socialist German Workers’ Party, was about to deliver a speech to kick off the opening ceremonies in the capital city. British operatives knew it all. They even found out what time the Luftwaffe commandant was due to step to the podium at the Air Ministry Building—exactly 1100.

Royal Air Force leaders had dispatched orders to a pair of Mosquito squadrons experienced in low-level attacks. “I was playing [cards] in the crew room when my driver first told me we were going on an op,” Sergeant Richard Charles “Lofty” Fletcher later told reporters. “I must admit I was a bit shattered when I found out it was Berlin.”

The 400-mph Mosquitos were undertaking the RAF’s first daylight bombing attack on Germany’s largest city. Their target was not the parade route or even the Reichsmarschall himself, but something bigger. It didn’t take a top-level English spy to figure out that Göring’s remarks would be transmitted to the far corners of the Third Reich. The bombers banked and streaked towards Berlin’s Haus des Rundfunks—the headquarters building of the German State broadcasting company.

Göring and the radio building were slightly more than four miles apart—a distance that the Mosquitos could cover, going all-out, in roughly 40 seconds. And the cacophony they brought with them traveled even faster. As the mics went live and Göring began to speak, the roar of impending catastrophe became audible over the radio.[]


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love

First online ham radio exam in the USA

(Source: Southgate ARC)

The first remote all-online amateur radio Technician license exam was carried out in the United States on March 26, 2020

Marcel Stieber @AI6MS Tweeted:

Yesterday [March 26], our working group ran an “all-virtual” amateur radio technician license exam for the first time in history! Thanks to @W5YI for being supportive of this effort. Stay tuned, we hope to have a scalable solution available for broader use soon!
https://twitter.com/AI6MS/status/1243772831415988225

Joseph Talbot sat the exam and his FCC Technician license callsign KJ7NNU was granted on March 27. His entry in the FCC database can be seen at
https://wireless2.fcc.gov/UlsApp/UlsSearch/license.jsp?licKey=4267101

Since 2010 there have been other exams sessions carried out remotely but they have had an in-person proctor present at the exam session. This was the first remote online Technician exam session carried out with everybody online.

On March 15 Sam Hulick had tweeted Ajit Pai, Chairman of the USA’s communications regulator FCC, asking:

Please open up amateur radio exams/licensing remotely. People should not be attending physical classes to be able to obtain a license.
https://twitter.com/SamHulick/status/1239259361932906497

FCC Chairman Ajit Pai speedily tweeted his reply just 14 minutes later
Thanks for the suggestion. Let me look into this—stay tuned
https://twitter.com/AjitPaiFCC/status/1239262974939971585

On March 24 Stirling Mann @N0SSC reported Remote Testing Working Group Underway
http://n0ssc.com/posts/1044-anchorage-vec-remote-testing-results-in-a-new-extra-remote-testing-working-group-underway

Spread the radio love