Patricia hears a mystery signal on 7075 kHz

Many thanks to SWLing Post contributor, Patricia, who writes with the following inquiry:

I wonder if anyone has heard and identified the station or signal I heard on 7075 kHz at 0745 October 30, 2021 on my C. Crane Skywave, and I live in southern California. I would like to know where this signal originates, sounding something like a numbers station, no voice, but a whooshing sound. I have heard it may be a ham frequency or a signal from space. Any ideas?

Thanks,

Patricia G.

Thank you for your question, Patricia.

I believe what you’re hearing is the ham radio digital mode called FT8.

FT8 is a weak signal digital mode that is extremely popular in the ham radio world these days. The mode isn’t designed around relaying lengthy messages, rather it’s designed for short, very formulaic exchanges.

Each message of up to 13 characters takes 13 seconds to send. For FT8 operators to be successful, they try to keep very accurate timing on their computing device controlling the transceiver. When the whole group is coordinated well, you’ll hear groups of signal tones singing all at once in 13 second intervals with a couple seconds of space between messages.

Here’s what FT8 sounds like in SSB mode:

It’s possible it sounded quite different, however, if you were listening in AM mode.

If this doesn’t sound like what you heard, perhaps you can check the comments for any other possibilities, but my guess is it’s FT8 as it’s a pretty strong chorus of tones!

Great question, Patricia!

Spread the radio love

Radio Waves: Broadcast v Ham Radio, Marjorie Stetson’s Secret Wartime Work, Czech Republic MW Switch-Off, and PV RFI

3 Replies

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!

Alike, but Not Alike: Broadcast vs. Ham Radio (Radio World)

Experience in amateur radio can be a boon to the radio engineer

Starting in the 1920s and through the ’60s, almost every broadcast engineer was a licensed amateur radio operator. That has changed a bit, but the importance of being a ham has not.

Both environments involve getting an RF signal from Point A to Point B. But it is interesting to note that radio broadcast and amateur radio are similar and yet so different.

For those who don’t know much about ham radio, I’ll tell you that communicating locally or internationally, via licensed amateur radio, can be a fascinating and challenging hobby. There are about 700,000 hams in the U.S. and an equal number worldwide.

Physics

Broadcast and amateur radio operate under the same laws of science. Transmitters, transmission lines, antennas and receivers make up an RF path to convey a message.

Broadcast engineers know that signal propagation on AM and FM bands is dramatically different. It is because our FM band is roughly 100 times the frequency and 1/100th the RF wavelength of that on the AM band. Engineers also know that 950 MHz STL signals are line-of-sight and roughly a 10-times jump in frequency from FM broadcast frequencies. Each band has its own challenges in getting a useable signal through. [Continue reading…]

A Canadian opens up about her secret wartime work — eavesdropping on Japan (CBC)

Retired sergeant remembers what it was like on the ‘front line of the radio war’

At age 97, Marjorie Stetson has never told anyone her secret code number — until now.

That’s the identity code — 225 — that she typed on every page of her highly classified work for the Canadian Armed Forces during the Second World War.

The retired sergeant’s wartime work was so covert, she said, she had to sign 15 separate copies of Canada’s Official Secrets Act.

“Nobody knew where I worked,” Stetson told CBC News from her home in Massachusetts ahead of Remembrance Day. “Nobody knew what we did. Even my parents never knew what I did in the service.”

Her husband, an American sailor she met at a celebration marking the end of the war, passed away a decade ago. She never told him what she really did during the war.

Today, Stetson herself is only now learning about the true scope of her role and the significance of all those sheets of white paper she filled with encrypted messages from Japan. [Continue reading…]

Czech Republic: MW Switch-Off by 2021 (Radio Reporter)

Czech public radio ‘?eský Rozhlas‘ is stepping up its information campaign for listeners receiving mediumwave programmes, ahead of the planned switch-off of transmitters by the end of 2021. Since 1 November, more announcements have been broadcast to warn users and a call centre has been set up to explain the possible listening alternatives (from FM to DAB). In the run-up to Christmas, public radio will launch an intensive advertising campaign in the print media and online magazines on 22 November to promote the purchase of digital DAB receivers to replace analogue radio. [Continue reading…]

The impact of photovoltaics (Southgate ARC)

Seamus Ei8EP reports on the IARU Region 1 website that the 358 page Final Report on the Study on the evaluation of the Electromagnetic Compatibility Directive has now been published.

It is publicly available, free of charge, from the Publications Office of the European Union. The Political Relations Committee of the IARU Region 1 responded recently to a European Commission Roadmap on the environmental impact of photovoltaics.

The radio spectrum is an important finite natural resource which must be protected. While PV technology of itself is to be welcomed, the IARU submission pointed out the inherent problems of non-compliant installations, particularly the installation or retro-fitting of optimisers which can produce significant spectrum pollution for very limited efficiency increase.

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

FTIOM & UBMP, November 14-20

Travel radio decisions: Jack seeks your input!

31 Replies

Many thanks to SWLing Post contributor, Jack Kratoville, for the following guest post:

Important travel decisions…

For the first time, (in a very long time), I’ll be traveling outside the country. This will be my first visit to Germany, and while I’ve already put Thomas’ packing skills to the test domestically with moderate success and confidence, I thought I would ask for assistance on what radio to bring.

The following is what I have, along with my current personal pros and cons regarding each one for this specific trip. I’m traveling with my wife, daughter & mother-in-law and staying with her family. This probably excludes a lot of alone time dedicated specifically to radio listening and DXing.

Now, from what I’ve been reading, MW and LW have been eliminated in favor of digital signals. This changes the equation a bit. Lack of SSB is NOT a deal-breaker. The amount of time I spend listening is miniscule. Here’s the receivers:

CC Skywave

The CC Skywave

This has been on every domestic trip I’ve taken since its purchase in 2015. Perfect size (even with the hard case) and excellent performance. Two quality AA batteries will last for 2 weeks easily. However, my favorite feature, WX, is useless there. Best MW reception in an ultralight, but does that matter in the land of DAB? Assuming there’s no LW to listen to either, the Skywave’s lack of it shouldn’t factor in. I like the Skywave’s super-fast scanning, but I think I’ll wish I had the ETM feature of other radios. I’ve used the Air Band, but I won’t be staying anywhere near an airport and I doubt I’ll be sitting in an airport with an extended antenna anytime soon. Non-digital audio control gives me exact control to go “unnoticed” if others are sleeping. The lack of ETM may keep this unit home.

Tecsun PL-360

Another favorite travel companion that does feature ETM, this radio is small and compact – and my unit still works like new. I can recharge the batteries with a computer cable, not that it’s ever shown high power consumption. I had thought this was a front runner, but tinny audio and that extra antenna to lose is giving me second thoughts. It’s physical build lends to more hand-held than bedside table use and that is definitely a factor worth considering. Analog audio control, but it has gotten noisy.

Digitech AR1780

The Digitech AR1780

Has it all: LW/MW/Air/FM(RDS)/SSB and fantastic audio. For positives, it checks all the boxes. It is a slow scanner – and that is a persistent downside. Further considerations, I’m committed to carry-on travel only (European dimensions!) and this receiver will command more real estate in the bag. Now if I didn’t need to pack socks for a couple of weeks… I may also be shoving a radio in my pocket for those “here’s-what-we-have-planned” moments and I don’t want to look like I’m obviously addicted to my hobby. With that non-existent charging cord, four replacement double-A’s might also be an issue if I do use it for any reasonable amount of time. I had considered this a shoe-in when we first talked Germany prior to pandemic, but it seems more unsuitable every time I weigh the pros and cons.

Tecsun PL-310ET

The PL-310ET

A radio gifted to me that was immediately assigned to basic alarm clock duty bedside – now surprisingly is part of the discussion. Not enough sizzle to replace my favorites domestically, but it may have the right combo for a few weeks in Germany. Quick scanning, ETM, multiple tuning modes, a decent speaker. Unlike the PL-360, you can’t “fast-tune” with the knob, but you can direct-input frequencies. I would miss RDS on FM, but I’ve scanned most of my life without it. Now, I’ve had a few other Tecsuns (along with the Grundig G8) and they all eventually fail with tuning and volume knobs (the PL-360 is the honorable exception). Since I haven’t used this unit much, I’m confident it’s well before its failure phase, if it ever does. I am not a fan of digital volume knobs, but this one seems to be better balanced than most. Not sure how it does on 3 AA consumption, but I’m testing rigorously. I would have never guessed, but this is the front-runner at the moment.

Eton Traveler III

The Eton Traveler III

While I’ve enjoyed RCS and the adjustable lighted dial at the beach, I’m not impressed. Sounds and looks nice, but lack of user-friendly functionality has kept this unit from any serious travel. Not to mention a battery hog with 4 AAs!

What do you think?

While I might fantasize about making room for the Eton Executive Satellit or putting batteries back in my G5, I’m limiting choices to the above! I appreciate all input and any thoughts on radio listening in Germany. Please comment!

Any SW frequencies I should direct input? We’ll be staying just outside of Kiel, which could include a day trip to Denmark.

Now it’s off to Hodinkee for GMT watch suggestions.

Spread the radio love

Radio applications for an Oiiwak Digital Endoscope

Jock reviews the BHI Compact In-Line Noise Eliminating Module

18 Replies

Many thanks to SWLing Post contributor, Jock Elliott, who shares the following guest post:

The noise, the neighbor, and the box

By Jock Elliott, KB2GOM

Imagine the annual meeting of an international corporation called SWLing Inc. (or SWLing LTD). The CEO, looking splendid in his custom-tailored suit, is addressing the assembled multitudes. On the giant screen is an equation showing signal-to-noise ratio. The CEO aims his laser pointer at the word “signal.” We want ALL of this, he says. Then he points at the word “noise,” and says, “and NONE of this.”

Then he looks at the audience and says, “Got it?” And he walks off the stage.

That, whether they want to admit it or not, is the mindset of every single SWL, international music fan, overseas program listener, and DXer. Period. They want as much signal as they can get, and as little noise as possible. That’s what drives radioheads to buy amplified loops, to string long wires, to build towers and yagi antenna arrays, to lay out beverage antennas hundreds of feet long, and to build ferrite sleeve loop antennas . . . it’s all about the signal to noise radio. More signal, less noise.

And it was noise that was bothering me . . . a kind of hiss, hash, eggs-frying sound. It was that noise that prompted me to create the horizontal room loop to try to boost the signal coming into my Grundig Satellit 800 over the noise normally received on the Satellit’s whip antenna.

And it worked; there was more signal on top of the noise . . . but that hiss, hash, whatever you want to call it, was still there. I could hit the attenuator, and some of the noise would go away, but it was still there. After a while, it was just plain tiring on the ears. Poking around the internet, the wisdom seemed to be that the source of the noise was likely electric/electronic gear in my radio room. So I killed the power to everything in my radio room, powered the Satellit 800 off internal batteries, and the noise was still there.

So I called my neighbor. He’s (a) a really good neighbor, (b) a ham with a serious station, and (c) technically knowledgeable. I explain the problem. He says, “Meet me outside.”

We meet between the yards, and he has a Sony 7600 portable shortwave radio in his hand. He switches it on. “Is this the noise you’re talking about?”

“Yup,” I say. “That’s the atmosphere,” he says. Well, nuts.

More poking around the internet reveals that an amplified receive-only magnetic loop antenna might be significantly quieter, and there are several manufacturers of them. I’m thinking about one of those loops when I run across a review of a relatively inexpensive ham transceiver that is reported to be excellent at pulling difficult signals out of the noise because of the superior “digital signal processing” (DSP) that is built into the transceiver.

Digital signal processing . . . that sounds promising . . . after all, if you take a step back and think about it, there are two ways to improve signal-to-noise ratio. One way is to improve the signal with better antennas and the like. The other way is to reduce the noise, and one way to achieve that might be through digital signal processing.

So, are there any companies that make external digital signal processors that could be used with an HF receiver? There are several, it turns out. Some of the units are large, studded with knobs and look complicated to operate, and almost all of the offerings require an external power supply.

But I wanted something that could be easily transferred between receivers and might even be used with a portable receiver when I was doing my horizontal DXing in bed. A big box that requires an external power supply was going to be awkward, cumbersome, and inconvenient. And that’s when I ran into a British company called BHI. They make noise cancellation products, gizmos that use digital processing to remove noise from an audio signal. They serve amateur radio, commercial, marine, medical, and even covert surveillance markets.

One of their products is the Compact In-line Noise Eliminating Module. It can be run off AA batteries and isn’t much bigger than a deck of cards (in fact, its footprint is almost exactly the same as my CCrane Skywave SSB). It has just two knobs and is easy to set up: you just plug it in between your HF receiver and your headphones or external speaker. It even comes with a cable to connect your receiver to the Noise Eliminating Module.

I order one from DX Engineering in Ohio. The cost, delivered to my door, including tax, is just over $260 American dollars. It arrives two days later, just in time for the bands to be sizzling with noise (apparently) produced by a solar coronal mass ejection (CME). The amount of noise is brutal, about as bad as I have ever heard in decades of hamming and SWLing.

Plugging the BHI in-line module into my Satellit 800 and clamping the headphones over my ears, I begin tuning the 20-meter ham band. Part way up the band, I run into a Canadian ham chatting with someone. His signal is barely above the noise and copyable, but the noise is really annoying. I punch the button for the BHI device, and . . . the noise disappears. Wow! I press the right-hand button (to bypass the BHI device), and the noise comes back full force.

Quickly, I grab my Tecsun PL-880, extend the whip antenna, tune to the same frequency, and plug the BHI in-line module into the 880. The noise sounds even worse on the 880 (the Canadian ham is barely copyable), probably because of the shorter antenna. But when I engage the BHI device, the result is even more dramatic; a very pleasant signal emerges as the BHI unit suppresses the noise, with just a bare hint of hiss still audible.

Then I take hold of my CCrane Skywave SSB to see how the BHI in-line module will behave with that. It doesn’t take long to realize that, apparently because of the solar activity, all the bands are noisy on the Skywave. Not just shortwave, but AM, FM, weather, and Air were all uncharacteristically affected by hiss or noise. The BHI Compact In-line Noise Eliminating Module reduced the noise and made each of them more pleasant to listen to, without exception. I am “officially” impressed.

As I experiment with the BHI device in following days, during which atmospheric conditions improve, I continue to be impressed. Why? Because the BHI Compact In-line Noise Eliminating Module is effective at substantially reducing noise without a lot of fuss and bother.

As good as the BHI module is, though, it is not a miracle device; it does have some limitations. Sometimes it will not eliminate all the noise, even though the noise will be reduced substantially. If you crank up the level of filtering/noise cancellation too high, it can distort speech and make tuning single sideband difficult. Further, you sometimes hear artifacts of the digital signal processing. These artifacts sound to me like trickling water, and, frankly, I don’t find these sounds objectionable (they sure beat the heck out of the atmospheric noise), but some people, I suppose, might not like them.

Image via DX Engineering

The module is easy to operate. There are two knobs. Press the left one in to power up the unit, then turn the knob to adjust the volume. Press the right knob to activate noise reduction and then turn the knob to adjust the level of noise reduction. Sometimes, I find, the sweet spot for listening is with the noise substantially reduced – perhaps 85-90 percent – but not completely gone. Press the right knob again to bypass noise reduction and hear what the signal sounds like without the BHI module online.

Because the two knobs on the face of the BHI module are also push-buttons, if you are going to pack the device in your luggage, remove the batteries to prevent the unit from inadvertently turning on and draining the batteries.

Bottom line

The BHI Compact In-line Noise Eliminating Module is highly effective at reducing or eliminating noise. It works on international broadcasters, ham single-sideband signals, and utility stations, as well as AM, FM, and even NOAA weather radio when conditions are horrible. It can make weak signals easier to hear and strong signals more pleasant for long-term listening. It reduces audio fatigue. It is not a cure-all for all signal-to-noise or audio problems, but it is a big help. Further, it can be readily moved from location to location and from radio to radio and adds a new capability to receivers that do not have built-in digital signal processing.

I think it is a worthwhile addition to any shortwave listening post.

Spread the radio love

Radio Waves: Radio and Education, Border Blasters, FM Switch Delayed per DCMS, and A Quick Temporary AM Antenna

4 Replies

Radio Waves: Stories Making Waves in the World of Radio

Can Radio Really Educate? (JSTOR Daily)

In the 1920s, radio was an exciting new mass medium. It was known for providing entertainment, but educators wondered if it could also be used for education.

It was mid-1922 and America was in the midst of the radio craze. Commercial broadcasting had emerged in a handful of cities in 1920, but at that time, few people had a receiving set—except for amateur radio operators, who knew how to build one. It wasn’t even called “radio” back then—newspapers referred to it as “radiophone” or “wireless telephone.” But only two years later, there were several hundred radio stations on the air, and you could purchase a radio in a store—although hobbyists still had fun trying to build their own, with varying degrees of success. Meanwhile, the word “radio” had become the common term for that wonderful new invention that everyone wanted in their home.

Today, we tend to take radio for granted; it is one of many ways to hear music or news or sports. But in 1922, radio was unique: it was the first mass medium to take people to an event in real time, and listeners were amazed by it. Suddenly, they could hear a popular orchestra coming through the radio set. Without leaving their home, they could listen to a baseball game, or an inspirational talk from a preacher; some stations even had the latest news headlines. In an era when traveling from one city to another could take hours (the popular Model T Ford had a top speed of 40-45 mph, and superhighways had not yet come along), listeners could travel by radio, hearing stations from distant cities. Before radio, only the wealthy could attend a concert featuring a famous vocalist, but now, anyone who had a receiving set could hear that singer’s music. And in an America that was still racially segregated, radio gave some musicians of color the opportunity to be heard by thousands of listeners. In magazines and newspapers, radio inspired “utopian hopes and bold predictions.” Writers referred to it as a cure for loneliness—especially for people living in rural areas or on the farm. It was also praised for helping the blind gain greater access to the world around them. More than one writer claimed radio would bring world peace, since everyone would unite around their favorite programs. And of course, as a sign of American progress, it was something no home should be without, not even the White House: President Harding was an enthusiastic radio fan, and had a set installed near his desk, so he could listen whenever he wanted to. [Continue reading…]

Psychics once ruled the airwaves thanks to the Texas-Mexico border and the magic of radio (KUT)

A new book includes details of how powerful radio stations along the border helped former vaudeville actors reach larger audiences.

In the 1920s and ’30s, some of the most popular radio programs in the United States featured radio psychics. The most successful among them made hundreds of thousands of dollars reading the minds and predicting the futures of eager listeners. To do it, they took advantage of a new and mysterious medium: radio. Continue reading →

Spread the radio love