Grimeton SAQ

On July 2nd 2004, UNESCO put Varberg Radio at Grimeton radio (SAQ) on the World Heritage List, declaring:

The Varberg Radio Station Online at Grimeton radio in southern Sweden (built in 1922-1924) is an exceptionally well preserved monument to early wireless transatlantic communication. It consists of the transmitter equipment, including the aerial system of six 127-m high steel towers. Though no longer in regular use, the equipment has been maintained in operating condition.The 109.9-ha site comprises buildings housing the original Alexanderson transmitter, including the towers with their antennas, shortwave transmitters with their antennas, and a residential area with staff housing. The architect Carl Akerblad designed the main buildings in the neoclassical style and the structural engineer Henrik Kreuger was responsible for the antenna towers, the tallest built structures in Sweden at that time. The site is an outstanding example of the development of telecommunications and is the only surviving example of a major transmitting station based on preelectronic technology.

Ernst F. W. Alexanderson, the foremost one to be honoured, was unfortunately not credited with his full name in the UNESCO declaration. Without Alexanderson, designer of the radio equipment and the antenna system, SAQ would never have succeeded in attaining world heritage status; this publication will show his role. SAQ is unique in another way being the only world heritage object to be visited far away by DX radio reception.

It started in the 19th century
In the 1860’s James Clerk Maxwell, then at King’s College in London, wrote a letter to his cousin saying: “I have a paper afloat which, til convinced to the contrary, I hold to be great guns.” In the 1870’s, he published his theory on electromagnetic waves which was confirmed experimentally by Heinrich Hertz ten years later.

Nikola Tesla’s work on AC for power and light applications included high frequency alternators and already in the early 1890’s he foresaw transatlantic wireless telegraphy employing continuous waves (CW). In May 1895, Alexander Popow demonstrated a receiver to predict arriving thunderstorms. It is rumoured and may well be true that he had sent wireless signals to ships, a fact then concealed by the Imperial Russian Navy.

Physicists and other scientists considered that this electromagnetic radiation was an interesting phenomena, no more. Guglielmo Marconi, an engineer and entrepreneur, realized that these waves could be used for wireless communication. In September 1895, he made his first experiments and, in 1901, he covered the Atlantic. Marconi became regarded by all, including Popow, as the father of radio, and was awarded the 1909 Nobel Prize in Physics, shared with Karl Ferdinand Braun, “in recognition of their contributions to the development of wireless telegraphy.” The word “radio” (from Latin radius, spoke) was used already by Hertz, but it took some decades until it was generally accepted as the most common expression.

In the beginning, emissions were generated by electric sparks producing damped waves, i. e. the signal amplitude decreased with time until the next spark occurred after about a millisecond. All stations were on longwave (for intercontinental traffic VLF, Very Low Frequencies; for shorter distances LF, Low Frequencies). Shortwave transmitters (HF, High Frequencies) did not appear until the 1920’s.

This system was restricted to morse telegraphy and had a wide radio spectrum limiting the number of stations on the air. At the turn of the century, constant amplitude CW became possible with the Poulsen electric arc converter and Goldschmidt, Arco-Slaby, B├ęthenod-Latour and Alexanderson types of rotary machinery. In the 1920’s, transmitting tubes had arrived and the famous Rugby station used these from its start in 1925.