Category Archives: How To

Pavel fixes a stereo lock in the Eton E1

Many thanks to SWLing Post contributor, Pavel Kraus, who shares the following guest post:

Eton E1 – fault in stereo reception

I recently became the owner of an Eton E1 receiver, which I obtained on eBay from the USA.

The receiver is great, everything worked, error-free display. The only problem was that even FM and strong local stations did not play stereo even though stereo reception was set in the menu. The stereo text on the display flashed several times when the stations were not tuned in precisely, but after the stereo tuned, the text went out. I know that stereo reception is not the most important thing for this receiver, but it bothered me that there was a defect at all.

The Sanyo 3335 stereo decoder is used in this radio. The stereo reception switching threshold can be set with a 10kohm potentiometer which is connected to terminal 4 of the integrated circuit:

I disassembled the radio by loosening the screws on the back of the radio. The receiver is divided into two parts. I removed the XM module and disconnected the part of the radio with the display from the flat wires on the second printed circuit board of the radio.

I then removed the screws on the circuit board located at the back of the radio.

I removed the printed circuit board and found a matching resistor trimmer on the other side of the circuit.

Then I connected these two points with a wire (when running on batteries) so that I could turn on the receiver:

After tuning in to a strong local transmitter, I carefully turned the trimmer until the stereo sign lit up and listening to the headphones made sure the sound matched the stereo. I repeated this at several local stations.

The receiver now plays stereo perfectly and the settings do not affect other parameters of the receiver. After assembling the radio, I was able to enjoy quality stereo reception.

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Guest Post: “Tinkering with History”

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Many thanks to SWLing Post contributor, Bob Colegrove, who shares the following guest post:

Tinkering with History

By Bob Colegrove

One of the attractive aspects of radio as a hobby is that it has so many specialties to channel our time. Just for the sake of classification, I would group these into two categories, listening and tinkering. I think the meaning of each category is fairly intuitive. Probably few of us approach our interest in radio in the same way. Most of us have dabbled in more than one listening or tinkering specialty. Perhaps we have been drawn to one particular area of interest, or we may have bounced around from one to another over a period of time. I know the latter has been my case.

Tinkering might start with a simple curiosity about what makes the radio play, or hum, or buzz, and progress to an obsessive, compulsive disorder in making it play, hum or buzz better. Unfortunately, over the past 30 years or so, the use of proprietary integrated circuits, as well as robotically-installed, surface-mounted components have greatly short-circuited what the average radio tinker can do. For example, I have noticed a lot more interest in antennas over that period, and I think the reason is simple. The antenna is one remaining area where a committed tinker can still cobble up a length of wire and supporting structure and draw some satisfaction. But the complexity and lack of adequate documentation have largely kept newer radio cabinets intact and soldering irons cold. Bill Halligan knew you were going to tinker with his radios, so he told you how they were put together. The fun began when you took your radio out of warranty. If you did get in over your head, there was usually somebody’s cousin not far away who could help you out. The following is a sample of how one resolute tinker managed to overcome the problem of locked-down radios in the modern age. Continue reading →

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Giuseppe’s portable multi-loop homemade shoe rack antenna

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Many thanks to SWLing Post contributor, Giuseppe Morlè, who writes:

Dear Thomas,

I’m Giuseppe Morlè iz0gzw from central Italy on the Tyrrhenian Sea, Formia.

I am sending you this umpteenth project of mine built with poor materials…it is a test bench, loops / capacitors to find the best tuning.

The frame is a shoe rack in beech wood, very light, to take anywhere or to try out at home.
On the frame, there are 4 different loops of different sizes and 3 variable capacitors with different capacities. Only one signal transfer link to the receiver for all loops.

With alligator plugs I can use the different combinations of loop / variable to find the best tune

This test rig can tune the whole HF frequency range and medium wave.

I’ve attached 3 videos where you can see from the beginning to the last test on the balcony of my house.

Videos

Note that the following videos are in Italian, but you can turn on closed captioning and in the settings of the video have it auto-translate into the language of choice:

Click here to view on YouTube.

All, as always, spending very little and employing used materials!

Thanks to you and a warm greeting to the whole SWLing Post community.

I remain available for any clarification.

Greetings to all and good experimentation!

Thank you for sharing this Giuseppe! I love your ingenuity and spirit of experimentation! What a fun project that obviously yields excellent results!

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Presentation: Crystal Radio History, Construction, and Contesting

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Many thanks to SWLing Post Contributor, David Day (N1DAY), who shares the video presentation below, offering even more insight into his most recent guest post on the topic of crystal radio DXing.

David has also posted this presentation on his website and notes that he’s happy to share the presentation slides without copyright. David notes:

[…]I have purposely not copyrighted this work so that anyone is free to modify it as they see fit. The only thing I ask is that if you make changes that you do not copyright the derivative work as your own intellectual property so that others can benefit from your knowledge and build upon it as well.

That’s brilliant, David! Thank you.

Presentation:

Click here to view on YouTube.

Click here to check out N1DAY’s website.

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Guest Post: Pavel’s Raspberry Pi-based homemade multimedia internet radios

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Many thanks to SWLing Post contributor, Pavel Kraus, who shares the following guest post:

Raspberry and internet radio

by Pavel Kraus

Raspberry and Volumio

I recently read an article about a Raspberry microcomputer here and I would like to introduce you to an idea that is easy to implement, not too expensive and does not require special computer knowledge due to the number of detailed instructions on the Internet. With Raspberry and the Volumio free software audiophile system, it is possible to design devices that allow you to play music files from connected or network storage or listen to Internet radio, etc. You can also play music from Spotify using the available plugins.

The system can be controlled by touch from the built-in display, from a mobile phone or tablet or by remote control. There are a huge number of internet radios, you can search them by genre or by country. For example, radio stations in the United States are categorized by state, in each state by city, and we can select individual stations in that city.

Volumio is the name for the project, which is presented at https://volumio.com/en/.

There is also the option to download this software and install it on a microSD card. Detailed documentation is available at https://volumio.github.io/docs/, so I will not describe it in detail here, the installation itself is not complicated. I used the following components to make this device: Continue reading →

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Guest Post: Crystal Radios – Construction, Listening, and Contesting

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Many thanks to SWLing Post contributor, David Day (N1DAY), for sharing the following guest post:

Crystal Radios – Construction, Listening, and Contesting

By David Day – N1DAY

The date was November 2, 1920 and the world was about to change forever when radio station KDKA out of Pittsburgh PA made its first broadcast of election results from the 1920 presidential election. For the first time in history people knew who won the election before reading about it the next day in the newspaper. Radio had arrived!

However, hearing the election results was not as easy as powering up an AM radio receiver because radio electron tubes had only been invented a few years earlier and they were still too expensive for most people to afford in a radio set. After KDKA’s historic broadcast, large 50,000 watt stations began popping up in all major cities around the world. Even though a tube-driven radio was not yet commonplace, many people listened to these stations on their crystal radios. The frenzy around radio in the 1920’s was not unlike the excitement around cell phones and the internet today. If you didn’t have one, you were simply living in the past.

A family listening to a crystal radio in the 1920’s

Fortunately, in the early 1920’s the crystal radio had been around for a while and it was easy to make or purchase a completed set on a limited budget. The beauty of the radio was that it was a passive device needing no power source other than the radio station’s broadcast that was received by a good antenna about 50 feet long and 15 or so feet above the ground. Crystal radios derived their name from use of galena crystals as detectors. Continue reading →

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