Tag Archives: Crystal Radio

Radio Waves: Colorado Inmate Radio, Experimental Radio News 4, BBC World Service to Ukraine, DIY Radio, and When the World Tuned to Shortwave

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!


Inmate-produced radio station streams beyond prison walls (NBC News)

Inside Wire, available 24/7 to incarcerated people in Colorado and to online listeners around the world, is said to offer a chance for prisoners and those they harmed to heal.

LIMON, Colo. — Herbert Alexander stares at the sound waves jumping on the computer screen in front of him, his shaved head partially covered by headphones. He’s editing a short audio feature on incarcerated fathers, a subject with which he is intimately familiar.

His two sons will soon hear his voice and his story because Alexander, 46, an inmate at Limon Correctional Facility, is preparing a segment for Inside Wire: Colorado Prison Radio, billed as the first radio station to be produced inside a prison and available to the world outside.

Other radio stations created in prisons generally air only within the walls of their lockups, but Inside Wire, which premiered March 1, reaches all 21 prisons in the state and beyond, online and by app, making the first of its kind in the country, organizers said.

“In spaces where isolation continues, this medium can cut through that,” said Ryan Conarro, general manager and program director of Inside Wire and creative producer for the University of Denver Prison Arts Initiative, which oversees the program in partnership with the Colorado Department of Corrections. [Continue reading at NBC…]

Experimental Radio News 4 (Experimental Radio News)

This issue of ERN includes novel aeronautical experiments, life-detecting radars and non-wearable health monitoring, the latest on those mysterious shortwave trading stations and more.

Click here to read a wide variety of topics in Experimental Radio News 4.

BBC World Service resurrects shortwave broadcasts in war-torn Ukraine (TPR)

The BBC has resurrected an old school way of broadcasting in order to reach people in the crisis area of Ukraine: Shortwave radio. What is shortwave, and why has the BBC decided to begin using it again? Continue reading

Spread the radio love

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

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

Spread the radio love

Bill’s first DX contest using a Panasonic RF-2200 and a hombrew diode/loop radio

Many thanks to SWLing Post contributor, Bill Hemphill (WD9EQD), who shares the following guest post:


My First DX Contest

by Bill Hemphill, WD9EQD

Being a recent new member of NJARC, this is my first time competing in this contest.  I have always been a big fan of BCB DXing and have recently got back into it – especially with the amateur radio bands being in such poor conditions.  The acquisition of a couple of Loop antennas plus two Panasonic RF-2200 radios have just enhanced my enjoyment.

For the contest, I used two completely different radios.  First was the RF-2200 and second was a spur of the moment creation.

The RF-2200 was its usual good performer. While the RF-2200 has a beautiful built-in rotating bar antenna, I enhanced it with the 27” Torus-Tuner Loop Antenna as made by K3FDY, Edmund Wawzinski.  I think I had picked this antenna up at one of NJARC’s swap meets.  So I wish to thank whoever it was that was nice enough to bring it and sell it at the meet.  I have really enjoyed using it.  With this setup, I was hoping that I might be able to pull in Denver, Salt Lake City and maybe even a Mexican station, but it was a complete bust on them.  But I did have a nice surprise in receiving the Cuban station Radio Enciclopedia on 530 in addition to the usual Radio Reloj time signal station.  Following is photo of it in operation:

Originally, I had thought that my second contest entry would be done with a 1962 Sony TR-910T three-band transistor radio.  This radio has a fairly wide dial along with a second fine-tuning knob which would be a big help.  I would have again used the 27” hula-hoop antenna.

But I made the nice mistake of running across Dave Schmarder’s Makearadio website:

http://makearadio.com/

Dave’s site is a wonderful resource for creating your own Crystal, Tube, and Solid State radios as well as Audio Amplifiers and Loop Antennas.  While going down the rabbit hole of his site, I ran across his Loop Crystal Set, #19 Crystal Radio:

http://makearadio.com/crystal/19.php

What grabbed my attention was the wood frame loop antenna which is similar to one I had acquired a couple of years ago at a ham fest:


It was a really nicely constructed, nice swivel base.

I replaced the tuning capacitor with one that has a 6:1 ratio.

At this point I started thinking that I could create something similar with my loop.

I randomly grabbed a diode from my parts box.  Not sure what the exact model is.  (I later found out that it was an IN-34 which is what I was hoping it was.)  Then quickly soldered the diode, a resistor and capacitor to a RCA plug:

I then proceeded to use some jumper cables and just clip it to the tuning capacitor on the antenna base:

The RCA plug was then the audio out (I hope) from the radio.

I quickly realized that I did not have a crystal headset or any headset that would reproduce any audio.  So I used an old Marantz cassette recorder to act as an amplifier.  Fed it into the mic jack and then tried to listen to the monitor out.  Bingo – I could pick up or local station on 1340 really weak.

So I then fed the audio from the Marantz into a Edirol digital recorder.  Now I was getting enough audio for the headphones plus could make  a recording of the audio.

At last I was receiving some signals.  To boost the audio some more I removed the resistor from the circuit.

I found out the I could only tune from about 530 to 1350.  I probably needed to clip the lead on one of the loop turns, but I really wanted to see how it would do at night.  I spent several hours and was just totally amazed at how well it performed and how good the audio was.  The hardest part was when there were very strong signals on the adjacent frequency.  What I found really interesting was that it was not linear in its tuning.  At the low end of the band the stations were more spread out than at the higher end.  This made tuning fairy easy at the low end and very touchy at the high end.  I was able to hear a couple of Chicago stations along with Atlanta and St. Louis.

Here’s photo of it in action:

I have created an audio file of the station ID’s heard with the diode/loop radio.  The audio file is on the Internet Archive at:

https://archive.org/details/bcbstationidsondioderadio

I had a lot of fun in the contest and especially enjoyed trying something really different with the diode/loop radio.  Now I have a whole year to try to think up something really creative for next year’s contest.


Absolutely brilliant, Bill! I’m so happy to see that your ham fest homebrew loop has served you so very well in a contest. I love how you pulled audio from your homebrew, make-shift diode radio as well–using your audio gear in a chain for amplification obviously worked very well.

Thanks so much for sharing your experience, Bill!

Spread the radio love

Andy seeks advice on directly coupling an AM loop antenna to a crystal radio

Andy would like to couple a similar antenna to a crystal receiver

Many thanks to SWLing Post contributor, Andy, who asks the following question in response to a previous post about building a Milk Crate AM Broadcast Loop Antenna:

All references to tuned loop antennas talk about no real connection to the AM radio, but merely inductive coupling.

However, I made a very elementary crystal radio which has no ferrite core or antenna.

I want this loop to be my primary (only) antenna, so I need to feed it directly to my tuning circuit. So I don’t know if I should take a wire from any particular part of the loop, with another wire to ground… and if these 2 wires should be in parallel or series with the tuning elements of the loop antenna.

Thanks!

Good question, Andy! Hopefully someone in the SWLing Post community can comment with some guidance!

Spread the radio love

Credit Card Crystal Radio

Many thanks to SWLing Post contributor, Paul Evans, who shares this article from Hackaday that highlights a crystal radio built completely on a smart chip credit card by Billy Cheung.

Hackaday notes:

This is possible because the smart chip on many credit cards contains a diode. It’s then a simple matter of hooking up the right pads on the credit card to the rest of a crystal radio circuit, and you’re all set. Of course, [Billy] goes the whole hog, building the entire radio on a single credit card. Other cards are cut up to create bobbins for winding coils to form a variable inductor, used to tune the radio. Doing this allows for a much cleaner, thinner design, rather than using a variable capacitor which is comparatively hard to find. Turning the dial allows stations to be tuned in, and with a high impedance earbud hooked up, you’re listening to AM radio. Oh, and don’t forget an antenna!

Cheung documented the whole process and even shares templates via links in the description of his YouTube video.

Many thanks to Paul and Hackaday for sharing this fun project!

Spread the radio love

AM radio from a hand-wound coil and an oxidized British penny

Many thanks to SWLing Post contributor, Paul Evans, who shares the following video and article via Hackaday:

There’s been a spate of apocalypse related articles over the last few weeks, but when I saw an AM radio made from a hand-wound coil and an oxidized British penny, I couldn’t help but be impressed. We’ve covered foxhole radios, stereotypical radios that are cobbled together from found parts during wartime.

This example uses a variable capacitor for tuning, but that’s technically optional. All that’s really needed is a coil and something to work as a diode. Surprisingly, copper oxide is a semiconductor, and the surface oxidation on a penny is enough to form a rudimentary diode.[…]

Click here to read the full article at Hackaday.

Thanks for sharing this, Paul. I absolutely love simple receivers like this one. In the past, I’ve built several crystal radios and had great success hearing local AM broadcasters. Indeed, the very first kit I ever built was a crystal radio, then later a foxhole style receiver.

Post readers: Have you ever built a radio similar to this one that uses an oxidized penny?  Please comment!

Click here to read posts from our archives that focus on crystal radios.

Spread the radio love

Back when Superboy encouraged kids to build radios with razor blades

Talk about hitting all of my nostalgia points! Hat tip to SWLing Post reader, Mitch, for sharing this ad from a 1960s comic book:


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