A new type of modulation: BALANCED SSB

 

We know the advantages and how a "balanced audio cable" works: 

The signal to be transmitted is split in opposite phases onto the two conductors 

of the cable and brought back into the same phase position in the receiver - 

thereby canceling out the interference that is introduced into the cable.

I wanted to transfer this concept to a type of modulation: At the transmitter, the signal is split in opposite phases onto the upper and lower sidebands (USB and LSB) of the same frequency (!).  At the receiver, one sideband is phase-shifted and added to the other -  thereby canceling out the interference.

 

 

Which disturbances can be eliminated in this way? 

 

- Amplitude disturbances such as "cracking," "rumble," "thunderstorm disturbances," 

 etc. 

 

Which disturbances cannot be eliminated in this way? 

 

- Phase and fading disturbances in the propagation channel.

 

 

I built the transmitter and receiver using "GNU Radio" as an SDR. 

The transmitter is a "Hack RF" and the receiver is a "USB-RTL dongle".

TWINWIRE - LOOP for the 80m amateur radio band (distributed c - antenna)

I've been using this "twinwire loop" with great success for the 80m amateur radio band. There's a 1:6 balun at the feed point. The dimensions can only be given approximately. Therefore, it's important to leave the two stub wires longer and then trim them. The antenna is very narrowband. I've tuned mine for the upper CW range. The entire antenna was made from 300 Ohm twinwire.

 

 

 Such an antenna was previously described as a "distributed C antenna" 

for other amateur radio bands.

 

 

The first test with 50 watts transmit power in telegraphy seems promising.

(reversebeacon.net)

Radio meteorites

 

Early in my career as a radio enthusiast, back in the 1990s, I occasionally heard a "chirping" sound with a decreasing pitch on the 11-meter CB band. I could hear this phenomenon primarily when receiving single-sideband (SSB) signals during times of good long-distance propagation. Even then, I suspected it was an ionophere phenomenon. 

With the advent of web-based SDR receivers, which display a waterfall plot of the frequency spectrum in addition to the audible signal, I was able to rediscover these signals, especially above 20 MHz. I then realized that a distinction must be made between the "chirping" of so-called "floating radio buoys" and the signals that are actually of interest. The radio buoys usually have a stronger, more regular signal, while the radio transmissions from burning meteorites typically have a weaker signal and leave different patterns in the waterfall plot. In the vast majority of cases, the frequency of the "chirping signal" decreases as its intensity diminishes.

What causes this phenomenon? 

In my opinion, burning meteorites have an ionized tail with a certain electron density within it. Perhaps through interactions with the Earth's magnetic field, internal instabilities, turbulent currents, or electrostatic discharges, the plasma is stimulated at its resonant frequency, generating these "radio bursts." Since the density of the ionized meteorite tail decreases continuously, both the frequency and the intensity decrease. The fact that this phenomenon can be observed in the frequency range around 28 MHz suggests that an ionized meteorite tail has an electron density (ne) of approximately 10⁷ cm³.

1* radio buoys / 2* radio meteorites (?) 

 

For this image I used the web-SDR of SM1OII in Hablingbo, Gotland Island, Sweden 

An expert at the Leibniz Institute for Atmospheric Physics in Kühlungsborn, Germany, was kind enough to read the article above. He pointed out to me that radio emissions from plasma have been observed. Despite extensive technical efforts and considerable antenna gain this phenomenon has only rarely been detected. Furthermore, reflections of radio signals from the ionized meteorite tail could be mistakenly interpreted as radio emissions. 

At this point, I refer to the scientific publication entitled "Association Between Meteor Radio Afterglows and Optical Persistent Trains" by K. S. Obenberger, J. M. Holmes, S. G. Ard, J. Dowell, N. S. Shuman, G. B. Taylor, S. S. Varghese, and A. A. Viggiano.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JA028053

Here you can find web-SDR: http://kiwisdr.com/.public/

Italian version of the famous WIRELESS RADIO SET 19

 

Apparently, there was a company in the Italian capital, Rome, called "Stirer," that modified the Canadian version of the famous transceiver. The writing on the front panel is in Italian, while the writings inside is in English.

30 Watt shortwave power amplifier

 

I recently ordered and tested a this shortwave amplifier for shortwave. Its technical specifications were consistently good and surprised me. For 25 euros, you get a well-designed product. For extended use, the heatsink should be additionally cooled with a fan or replaced with a larger one.

 

The amplification gain is in between 6,2 dB and 7,7 dB.

 

The impedance matching to 50 ohms is good. 

(top: through the amplifier / bottom: through)

 

An antenna for mobile communication on the 80-meter amateur radio band

The antenna element is two meters long and 12 millimeters in diameter. At its top is an 80 µH inductor. The top capacitance consists of two flat profiles, each 1 meter long and 10 mm wide screwed onto a ceramic insulator.  A good counterpoise should be ensured. The resonance can be adjusted with a clamp on the coil. Naturally, the antenna is narrowband...

 

... and works surprisingly well.

Manuale per analizzatori vettoriali di reti a radiofrequenze (VNA)

 

Questo manuale di ordine pratico è stato compilato a cura di IW3 AFT nel giugno 2025.

Tutte le informazioni che trovate in questo manuale è frutto di una ricerca in rete degli argomenti inerenti al VNA.

Le varie traduzioni sono state eseguite con l’ausilio di GOOGLE e adattate secondo la visione dell’autore.

            

Buona lettura!

Giorgio - IW3 AFT

 

P.S.: Il documento è a disposizione libera di tutti. Non si assume nessuna responsabilità per eventuali parti di copyright perché il tutto, come sopra, citato è a libera disposizione in internet.

 

LINK DOWNLOAD:  

 

https://drive.google.com/file/d/1b8lpNv-AVfuJfU6uftcVSGZ3HS8TD0Y7/view?usp=sharing

"Lichtenberg - Gerät" für die Gestaltung von Holzoberflächen

Mit einem 800 Watt 230 V / 2kV Transformator aus einem alten Mikrowellenherd als Kernstück, habe ich dieses "Lichtenberg - Gerät" aufgebaut. Der Fußschalter (links im Bild) aktiviert einen Schütz, der die Spannung an die Primärwicklung des Trafos gibt. Sekundärseitig wird die Spannung über Zündkabel an die Elektroden gegeben, deren Griffe isoliert sind. Die grüne Kontrollleuchte geht an, sobald das Gerät eingeschaltet ist und dient somit auch zur Kontrolle der Sicherung. Die rote Leuchte geht an, wenn die Primärspannung am Transformator anliegt.

Das deutliche anziehen bzw. abfallen des Schütz informiert den Benutzer auch akustisch über den Spannungszustand an den Elektroden.  

Das Gehäuse und der Fußschalter sind mit dem Schutzleiter verbunden.

 

Das Gerät wurde weder verkauft, noch für einen professionellen Tischler hergestellt. 

 

 

coffee can antenna - 2m tuned lamda/2

This fantastic antenna was featured in the May 1983 issue of "73 Magazine," pages 54-55. 

Assembly was straightforward and problem-free.

 

 

   

 

 

 

"Pressespiegel" - Box

 

RAI Südtirol always broadcasts the reviev of the newspapers at a time

when I'm on my bike cycling to the office. 

Since this "voice recording module" has recently become available that can record

17 minutes, I built this box, together with an Arduino UNO, a HW-84 real-time clock, and a TEA5767 FM radio module, 

which always plays the latest "press review" at the touch of a button.