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PostHeaderIcon Princess Marconi visits Marshall radio site

There are no translations available.

A princess came to town last Wednesday. She was dressed in sensible black heels, thick pantyhose and a silken neck scarf. Eighty-eight-year-old Elettra Marconi Giovanelli, her hair a soft nest of fading blonde curls, was visiting West Marin to bear witness to her father’s electric legacy.

The princess is not the daughter of a king. She is royalty by marriage, having wed Prince Carlo Giovannelli in 1966. But her father, the legendary Italian inventor Guglielmo Marconi, looms large in history as the inventor of the radio.

Mr. Marconi founded his telecommunications company in 1897, the same year he sent out the world’s first open-sea wireless message.

In 1912, Mr. Marconi’s company acquired a number of radio stations in America, among them station KPH, in San Francisco. In order to create a signal powerful enough to cross the Pacific, a receiving station was built in Marshall and a transmitting station in Bolinas.

After World War I, the government sought tighter control over radio communication and in 1920 formed the Radio Corporation of America, which bought out Marconi’s holdings. Maritime service continued in Marshall until 1939.


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PostHeaderIcon A Remote Controlled WiFi Antenna Switch

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This article describes the design and construction of a remote WiFi Antenna Switch for HF that is an order of magnitude more economical than any wireless remote switch available today. It is limited in its power handling and frequency bandwidth, but I believe it is of great use for most of ham radio operators.


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PostHeaderIcon Low-Cost 2,4 GHz Duplex Telemetry

There are no translations available.

by Reinhardt Weber, DC5ZM

The idee of this project was the wish puting my sat-rotor YAESU G-5600 in the attic avoidung two heavy control cables. This requires a radio controlled duplex telemetry connection for sending the key status and get back the analog values of meters for azimuth and elevation.

The project schown is an universal implementation with 4 digital und 4 analog channels for general apllications and is not restricted to rotors.


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Click here to construction of PCB's


PostHeaderIcon RadioRivista report

There are no translations available.

The first ham radio presentation in this conference trip, I had with CN2017 in Ladek Zdroj, Poland, in the premises of a tourist resort “Zamek na Skale” (means “the Castle on the Rock”). While traveling to that event, I used a train from Krakow (Krakau) to Wroclaw (Breslau). The ride took around 3.5 hrs, so I spent that time by experimenting with Polish APRS network. Although my equipment included SCS Tracker / DSP TNC, I could not use it on the train because it could not get its power supply from the USB ports of my laptop. Instead I used 'Plan B': It was a USB interface RIGblaster Plug'n'Play for making the laptop's sound-card a packet modem, and Taiwanese GPS-mouse YIC GU93030SM-USB (Fig. 1). Having in mind travel conditions such as the 'Faraday cage' of the train construction, high voltage power lines over the railway composition, a relatively high speed of the train – circa 120 km/h, and geographical configuration of surrounding terrains and so on, it was not expected that signals sent by a small hand-held radio ADI AF-16 will reach many recipients, if any (Fig. 2 & 3).

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PostHeaderIcon Samuel F.B. Morse Sent the First Telegraphic Message May 24, 1844

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What was the first telegraph message? Sent by inventor Samuel F.B. Morse on May 24, 1844, over an experimental line from Washington, D.C., to Baltimore, the message said: “What hath God wrought?” Taken from the Bible, Numbers 23:23, and recorded on a paper tape, the phrase had been suggested to Morse by Annie Ellsworth, the young daughter of a friend. The success of the experiment would change forever the national communication system. But Morse wasn’t just interested in the telegraph.

Morse was also well respected for his paintings of people, like the self-portrait on the previous screen and this one of Mrs. David C. De Forest. He painted his subjects with honesty and insight. It was while returning from Europe to take his position as an arts professor at New York University that Morse came up with the idea of a communications system using the electro-magnet and a series of relays through a network of telegraph stations. In order to transmit messages in this system, he invented Morse Code, an alphabet of electronic dots and dashes. The system made communication across the country faster than ever before.

Western Union completed the first transcontinental telegraph line in 1861, dooming the Pony Express, but aiding forces in the Civil War. Mobile telegraph stations, like this one with hastily strung wires, connected scattered military units. President Lincoln kept up with events of the war through frequent dispatches from General George McClellan. One Confederate attack failed when soldiers became tangled up in Union telegraph wires strung from tree stump to tree stump. Morse probably never expected telegraph wires to be a booby-trap!

A generation or two ago, people would send telegrams to announce important news such as a new birth in the family. Ask your family if they have ever sent a telegram.



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