Category Archives: Antennas

Video: Giuseppe explains wiring/construction of DICA Homebrew Antenna

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

Dear Thomas and SWLingPost Friends,

I’m Giuseppe Morlè iz0gzw,

Many friends have asked for the DICA wiring diagram after my recent post and demonstration.

I’m not a technician but a simple passionate listener and qrp’er… I made this video with a drawing that I hope will be useful to understand the details and how it works…

[Please note that this video is in Italian, but you can use YouTube Closed Captioning; it can even translate the subtitles into English or any other language.]

Thank you all.
Giuseppe iz0gzw.

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D.I.C.A.: Giuseppe’s latest homebrew portable antenna

Many thanks to SWLing Post contributor, Giuseppe Morlè, who shares the following antenna project:

Dear Thomas and SWLing Post Friends ,

I’m Giuseppe Morlè, iz0gzw, from Central Italy, Formia on the Tyrrhenian Sea…
Some time ago I had drawn this minimal HF antenna on paper…

I took advantage of the New Year’s Eve rain to be able to build it with the usual leftover scraps…

The system consists of a 35 cm tube with two separate windings of telephone cable on it, 2.5 m on each side, green and white…in the center I connected the 4 ends to X…

The green lead with the white and the white with the green to the variable capacitor and the other two leads to the RG58 cable that goes to the receiver.

I started the test and noticed that the agreement was possible from 7 to 21 MHz…

I then placed a long ferrite inside the tube…

I noticed a strengthening of the signal and consequently of the noise picked up and the chord dropped to 3.2 MHz.

Tests inside my shack showed decent reception on all ranges…in the evening on the balcony on 80 m. I could perfectly listen to a QSO between Italian stations.

Everything is still in the experimental phase and I think I will try this minimal system also in QRP transmission.

In this first video I explain how this minimal antenna is made:

The second video concerns a 20 meter test by car. The antenna is placed on the dashboard of the car inside:

In the third video, I explain how it works without the ferrite and with the ferrite inside the tube:

In this video you can see the test on 40 m. outdoors on the roof of the house:

The tests are carried out at home in order to understand what can be achieved in an environment that is difficult to receive.

I will do more outdoor tests and I think this small minimal antenna will receive better. I will keep you informed.

Thank you all for your attention and I wish you all a new year full of satisfaction.

’73 de Giuseppe iz0gzw.

Fascinating, Giuseppe! I love all of these brilliant little antennas you design out of your “junk” drawer! We look forward to hearing more about this antenna and any modifications you make to it!

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Andrew Ikin of Wellbrook Communications has passed away

Mark Fahey’s Wellbrook Mag Loop antenna.

Many thanks to a number of SWLing Post readers who sent me this message–a re-post from the IRCA mailing list:

Death of Andrew Ikin- Wellbrook Communications
From: Tracey Gardner
Date: Thu, 04 Jan 2024 13:10:23 EST

I am the bearer of very sad news.

My good friend Andrew Ikin of Wellbrook Communications passed away on 25th October 2023 after a very short illness.

He was buried on 10th November, a day before his 79th birthday.

He is buried in the local churchyard in Beulah.

Andrew was internationally known and respected, his products were second to none and his reputation for customer service renowned.

I was lucky enough to count him as a friend and I will sorely miss him.
The amateur radio and radio listener fraternity have lost a true colossus.

73s Tracey G5VU

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Jack recommends antennas from Lowbander’s Antenna Mart on eBay

Many thanks to SWLing Post contributor, Jack Dully, who writes:

Happy Holidays to Y’all!!! Thomas, I have bought about 5 antennas from the eBay seller”Lowbander” over the last few years. […]They are well constructed, strong and really bring in signals on the fringe. He has a small operation, I believe, but dedicated to making the best antennas he can. His antennas will last through storms and such but grab signals like a fly on honey, no kidding. Perhps other SWLing Post members don’t know of these excellent antennas at what I think is a good deal and worth the cost for years in the air. Thanks.

Clic here to check out Lowbander’s antenna offerings on eBay.

Note: this is an eBay partnership link–purchases support the SWLing Post at no cost to you.

Thank you for the tip, Jack!

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Radio Waves: The Discovery Dish Pre-Launch, China Radio International, Hackaday Prize, and Baseball Radio

Radio Waves:  Stories Making Waves in the World of Radio

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 Dennis Dura and Ulis (K3LU) for the following tips:


Discovery Dish Pre-launch: A Lightweight Dish And Feed For L-band Weather Satellites And Hydrogen Line Reception (RTL-SDR Blog)

For the past few years we have been working on finding the best way to help beginners get started with L-band weather satellite reception and basic radio astronomy. We have now come up with a solution that we’re calling the ‘Discovery Dish’ – a lightweight 65 cm diameter dish and active filtered feed set.

The Discovery Dish will be crowd funded, and we currently have a pre-launch page set up on Crowd Supply. So if you are interested, please visit the pre-launch page and click on the Subscribe button for updates.

Discovery Dish is a 65-cm diameter aluminum satellite dish and active filtered feed designed for receiving GOES HRIT, GK-2A LRIT, FengYun LRIT, NOAA HRPT, Metop HRPT, Meteor M2 HRPT and other weather satellites that operate around 1.69 GHz. The dish is designed to weigh under one kilogram, and it splits into three petals, making it easier to ship worldwide. The 1.69 GHz feed contains a built-in LNA right at the feed point, as well as filtering, which means that there is almost no noise figure loss from cables or connectors.

Note that the prototype images show an early non-petalized prototype with rough laser cut wind holes. The production version will obviously be a lot neater looking! […]

Click here for more details about the Discovery Dish campaign.

How China’s Propaganda Infiltrated Radio Stations in Europe (The Diplomat)

State-owned China Radio International is airing its content without attribution on commercial radio stations in Europe.

China has consistently and systematically pursued the dissemination of its narratives on the global stage, with the primary aim of shaping the international landscape to align with its strategic interests and ideological perspectives. These endeavors encompass a diverse array of tactics, including the acquisition of media enterprises, active engagement by Chinese ambassadors in both mainstream and fringe media outlets, the utilization of paid supplements, collaboration with pro-Kremlin media, and the steadily expanding presence of China across various social media platforms.

Recently, China Radio International (CRI), an official Chinese state media outlet broadcasting in multiple languages, has garnered attention for its establishment of partnerships with and provision of content to radio stations worldwide. Remarkably, CRI has effectively outsourced the production of China-related programming to local partners, often without transparently disclosing the sponsorship of content creation to the listeners. This strategy, known in Chinese as “borrowing a boat to go out on the ocean,” plays a pivotal role in laundering Beijing’s propaganda and fostering the acceptance of its messaging among local audiences.

One illustrative case of this approach within Europe involves two Czech radio stations, namely Radio HEY, a nationwide commercial radio station airing rock music, and Radio Color, which positions itself as “one of the last independent radios.” From 2019 to May 2023, these radio stations broadcasted a program titled “Barevný sv?t” (Colorful World), a nearly 30-minute segment aired six times a week, with the objective of acquainting Czech listeners with Chinese culture, language, and history. [Continue reading…]

Hackaday Prize 2023: A Software-Defined Radio With Real Knobs And Switches (Hackaday)

When cheap digital TV dongles enabled radio enthusiasts to set up software defined radio (SDR) systems at almost zero cost, it caused a revolution in the amateur radio world: now anyone could tune in to any frequency, with any modulation type, by just pointing and clicking in a computer program. While this undoubtably made exploring the radio waves much more accessible, we can imagine that some people miss the feeling of manipulating physical buttons on a radio while hunting for that one faint signal in a sea of noise. If you’re one of those people, you’re in luck: [Kaushlesh C.] has built a portable, self-contained SDR system with real knobs and switches, called SDR Dock 1.0.

The heart of the system is a Raspberry Pi running GQRX, an open-source SDR program that supports many different RF modules. [Kaushlesh] used an Airspy HF+ Discovery, a compact receiver that can work the HF and VHF bands, but it’s easy to modify the SDR Dock to accept other types like those ubiquitous RTL dongles. A seven-inch LCD screen with integrated speakers forms the main output device, with everything powered by a 10,000 mAh lithium-polymer battery. [Continue reading…]

With the future of AM unclear, a look back at the powerful role radio plays in baseball history (Citizen Tribune)

Many baseball fans, especially older ones, originally fell in love with America’s pastime by listening to ballgames on AM radio

Click here to browse this gallery.


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Martin builds a simple ferrite rod to inductively couple radios to his external mediumwave antenna

Many thanks to SWLing Post contributor, Martin Tobisch, who shares the following guest post and videos from his home in Malta:


New AM Signal Coupler

Many AM medium wave listeners are looking for solutions to improve the reception performance of their radios.

After many attempts, which I don’t want to entertain anyone with, a coupler was created that feeds the external antenna directly into the ferrite antenna. I use my 66 foot long wire antenna on 50 ohm RG-58 cable, but other antennas will have similar success.

The clips available on YouTube speak for themselves:

 

Experiments with smaller ferrites and antenna rods met with no success. It is important that the coupler still works even at a distance from the ferrite antenna and without precise alignment.

With tube radios it easily bridges the distance from the housing to the ferrite rod Antenna
The finished coupler consists of 6 NiZn ferrite cores, which are connected with glue to form a rod. 8 turns of wire are wound over this and soldered to an RG-58 cable. Some electrical isolation tape and ready. So far I’ve just put it in a box. Of course there are finer solutions and it should be protected against shock. Ferrite cores are notoriously brittle.

Here is a link to the ferrites used (purchased at AliExpress).

Advantages: Advantages to what? Nothing comparable exists.

So there are advantages to feeding via an antenna socket. The signal coupler is also good for radios without an antenna socket. But in case of using an antenna socket, common mode wave interference picked up in the house goes unlimited into the radio. Due to the magnetic coupling to the ferrite antenna, common mode waves are completely suppressed. They do not create a magnetic field in the coupler.

No changes are necessary in the radio

The biggest advantage is, that you can listen to distant stations loud and clear, which previously only produced a quiet scratching noise.

I very much welcome reports of experiences.

[email protected]

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A review of the outdoor Planespotter antenna prototype

Many thanks to SWLing Post contributor, Zach R., who shares the following guest post:


A review of the outdoor Planespotter antenna prototype

When it comes to airband monitoring, the stock whip antennas that ship with desktop and portable scanners are not the greatest. They’re fine if you’re at an airport and only interested in communications specific to your immediate area, but if you are someone like me who lives well out from any major airport, quality listening in can be impossible without some help in the antenna department.

Ideally, you want something like a discone or similar for omnidirectional listening, mounted as high as possible. This is not always possible or practical, however. SWLing Post contributor Ron recently reviewed the indoor Planespotter antenna, and I have one as well that works better than any rubber ducky, and can be easily hidden away when company comes.

Recently, the creator has come out with a prototype outdoor model. It’s the same design as the indoor unit, but with a longer run (25 feet) of coax, terminating in a BNC connector.

Besides the longer cable, the only other obvious change is the antenna is house in a skinnier PVC tube from the indoor model. It’s also sealed at the bottom so moisture won’t get in.

It has the same small metal hook on top, suitable from hanging from various mounts. I’d like more mounting options, but the hook does make for quick installation and removal. The half-wave length isn’t ungainly to handle and if painted it could easily be mounted on the side of a home without many people noticing.

The indoor version definitely works best on the VHF air band and seems to roll off aggressively above and below that band. The outdoor version, in side-by-side tests, seemed to perform the same on the air band but notably better on the VHF public safety band. It also pulled in more UHF air band traffic than the indoor model, despite being basically the same design.

The new outdoor version is a good choice for someone looking for a simple, already assembled antenna that’s suitable for temporary use or stealth mounting.

Disclosure: The outdoor prototype was supplied to me for free in exchange for a review. While taking more photos of the antenna I noticed the weatherproofing had come undone from the bottom. Hopefully this issue can be addressed before the antenna goes into production.

[Zach R. is the owner and editor of the Alabama Broadcast Media Page.]

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