Mile Kokotov's video: SAQ VLF Transmitter on 17 2 kHz receiving in Macedonia on Friday February 13th 2015

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. 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, Béthenod-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 -- - - - - - - - - - - - - - - - The Varberg Radio Station at Grimeton is a VLF transmission facility at Grimeton, Sweden. It has the only working Alexanderson alternator rotating armature radio transmitter in the world and is classified as a World Heritage Site. The transmitter was built in 1922 to 1924 to operate at 17.2 kHz. The antenna is a 1.9 km flattop wire aerial consisting of eight horizontal wires suspended on six 127-metre high freestanding steel pylons in a line, that function as a capacitive top-load to feed energy to six grounded vertical wire radiating elements. Until the 1950s, the Grimeton VLF transmitter was used for transatlantic radio telegraphy to Radio Central in Long Island, New York, USA. From the 1960s until 1996 it transmitted orders to submarines in the Swedish Navy. The Alexanderson transmitter became obsolete in 1996 and went out of service. However, because it was still in good condition it was declared a national monument and can be visited during the summer. On July 2, 2004, the Grimeton VLF transmitter was declared a World Cultural Heritage site by UNESCO. It continues to be used on special occasions such as Alexanderson Day to transmit Morse messages on 17.2 kHz. Its call sign is SAQ. The Grimeton/Varberg site is still used by the Swedish Navy, transmitting on 40.4 kHz using call sign SRC using the vacuum tube transmitter. Since the naval transmitter uses the same aerial as the Alexanderson mechanical transmitter, a simultaneous operation of both transmitters, which would require an expensive high power diplexer, is not possible. Therefore the special transmissions from that machine transmitter are very rare. Recent transmissions from SAQ on 17.2 kHz took place on February 13, 2015, with a CW message had being sent at 15:00 UTC. With Alexaderson 200 kW alternator, on international UNESCO ”WORLD RADIO DAY” (WRD) on Friday February 13th 2015. Tuning up started from 14:30 UTC and a message had been sent starting from 15:00 UTC. The message concerning PEACE had been put together by over 200 citizens of Varberg via the “Varberg Calling for Peace” project, in Varberg, Sweden. Receiving with AIRSPY-SDR + VLF Up-converter + Mini-Whip 10cm homemade active antenna. Distance between SAQ transmitter in Grimeton, Sweeden and Macedonia is about 1850 km. Mini Whip is excellent and cheap DIY active antenna. Especially for lower frequencies! (VLF up to lower HF bands) Some people who report poor performance of this antenna did not followed the rules of proper installation! Grounding the outer conductor (shield) of the coaxial cable has to be done properly! Coaxial cable is part of Mini-Whip antenna and collect a lot of RF noise. You can treat Mini-Whip antenna as a vertical antenna feeding at the top where the impedance is very high. Outer conductor of the coaxial cable must be grounded at the bottom of antenna, where the coaxial cable touching the ground, and the second grounding have to be done at the point just before coaxial cable entering in the house. The RF isolating transformer is recommend also. In that way receiver ground is not physically connected to antenna ground but it is galvanic isolated from outer shield of coaxial cable. All this measures is not difficult to implement and cost almost no money, but the benefit is clear, noiseless VLF and HF reception! Mini-Whip antenna must be placed as far as possible from houses, buildings and power lines! Here is the link of my Youtube video, with schematics of the Mini-Whip and Power supply (power inserter, or Bias-tee for powering the antenna thru the coaxial cable): https://www.youtube.com/watch?v=DiAO8tCtefc 73, Mile Kokotov, Z33T