[DX-TREME PROJECT]
In 1997, a group of 11m DX’ers with passion for propagation and antennas had a dream. Building a gigantic directional antenna, with a multi kilowatt transmitter. Not for fun, but to move the boundaries of what is possible on 11m, create a laboratory for propagation research, and just to feel the adrenaline rush as you operate the most powerful radio station on 11m of the world.
We had to wait for almost 13 years before we had the possibilities, financially and technologically to make the dream come true. A group of seven people got together and formed “Team Navarone”, named after the movie “The Guns Of Navarone”.
With the world economy at tragic depths, and the construction world without any large projects, we saw a large numbers of tower cranes waiting silently for a new assignment. By accident we ran into a building project in Northwest Europe that was set on hold, because the project owner had ran out of financial sources. Two 55m tower cranes at the building site stood there silently. We got in contact with the contractor, who told us the project was on hold until March 2011. We discussed the possibility to rent one of the tower cranes, and told the contractor about our project. Luck was on our side, as the contractor was an ex 11m DX’ers from the early 80’s. He agreed to rent us the tower crane for at least 9 months for a symbolic price, and his help with constructing world’s largest rotatable 11m antenna. The project and location was kept secret very well.
After many calculations, we decided to build a 21 element Delta Loop with a 33m boom length. Scrap metal was very cheap in 2009, so we bought large amounts of used aluminium tubing, for constructing the individual elements. All elements were mounted on top of the tower crane, which took us more than 3 months to complete. The construction was finalized on March 27th, when we installed the last few directors.
Next issue was choosing the transceiver. We knew that the tower crane carrying the Delta Loop could be remote controlled via a TCP/IP internet connection. So we decided to take advantage of this internet connection, and put a remote controlled Kenwood TS-480HX (owned by one of the members) in the crane drivers box. The TS480-HX is a compact transceiver which can be fully controlled via the internet with a TCP/IP connection. This would allow us to operate our transceiver with TX and RX audio streams and rotate the antenna array from any location in the world. Only equipment to control the entire setup is a laptop with separate microphone, Kenwood's remote control and audio software, Liebherr's crane driving software, and a broadband internet connection.
Because we were aiming to build the most powerful station in the world, we needed a reliable HF amplifier. Now the renown Australian manufacturer of HF linear amplifiers, Emtron, built only a few DX4 amplifiers. What a coincidence that one of these 5000W PEP amplifiers is owned by one of the “Club Navarone” members, and was not used actively…! So this amplifier was moved to join the TS-480HX. Both the radio and amplifier were mounted into a large aluminium casing, preventing any HF radiation leaking out. To handle the full 5000W we constructed the spreaders of the radiating element of copper tubing 28mm and 22mm. The horizontal wire connecting both spreaders is made of 16mm² copper welding cable, supported with fibreglass tubing. The amplifier is connected to the radiating element with 7 meters of extreme low loss GSM antenna coax. The 21 element Delta Loop provides a gain of over 22dBi, setting the ERP (effective radiated power) at 800kW PEP, comparable with the largest commercial shortwave broadcast stations!
After intense testing in the past weeks, we managed to get all 21 elements tuned to the magical 27.555 MHz. Running only QRP and reduced QRO power, internet control and audio streams were established and tested thoroughly. On Monday, March 29th, we took the complete array on the air with the TS-480HX’ original 200W, with some scheduled QSO‘s in the early morning. A few insiders which have followed our project, reported us a “broadcast station quality” signal at the other end of the globe.
We decided to get together once again on Wednesday evening to do a final test at full power, 5000W. When the test succeeds, we will go live on the air on Thursday, with a first CQ DX on 27.555 USB. Here is our transmission schedule for next Thursday:
0600 UTC : Pacific and New Zealand, longpath South America
0900 UTC : Australia, Japan, Eastern Asia and Middle East
1200 UTC : Africa
1500 UTC : North America, Central America and West Indies
1800 UTC : South America, longpath Australia and New Zealand
The DX-treme project will give us extraordinary possibilities to research propagation, and to look for propagation paths that seem closed with “normal equipment” . Some of the research projects we have planned are:
The most interesting part for our 11m friends, is the possibility to have complete control of this extraordinary station. Via the internet you have complete control of the direction of the tower crane, complete control over the TS-480HX and DX4 amplifier. You can use your PC's speaker and microphone to operate the radio.
Do you want to become a member of the selected team of operator which will receive the necessary passwords and username to enter the control program? Just click the link below to get your access to the most powerful radio station on 11m in the world, and if selected a chat window will open, allowing us to have contact with you while download the control software, and get the necessary instructions to connect to our extraordinary station.
DO YOU WANT TO CONTROL THE MOST POWERFUL RADIO STATION ON 11M IN THE WORLD?