The Arctic King rules the frigid North

By On · 4 Comments · In Amateur Radio
The Arctic King - 160 meter transmit antenna
The Arctic King – 160 meter transmit antenna

The Arctic King is finally built.

The project has taken more or less two years, it has consumed an incredible amount of heavy duty hardware and an enormous amount of hard work.

I enjoyed some assistance from my neighbors Finnbjörn and his brother Jón from Litlaeyri.

The antenna is designed by Villi, TF3DX and it will eventually work on both 160 and 80 meters and it will be possible to switch between vertical and dipole modes, which will give a choice of low and high angles of radiation.

Testing of the antenna will now begin, I have no doubts that the antenna will give me a strong signal on Top Band.

The efficiency of the antenna is in the vicinity of 75%, with 1.5 ohms in ground losses, this will later be confirmed  when final measurements have been carried out.

Note: Measurements have been made which confirmed this.

Due to the Salt Water propagation path for more than 180° and the closeness of the sea, the radiation angle is extremely low, this should help with very long distance contacts.

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  • Dave Arruzza W1CTN

    Any pics of the inside of the tuning box at the bottom of the antenna? I am assuming it is a tuner.

    73
    Dave
    W1CTN
    Radio Ansonia

    • http://tf4m.com TF4M

      There are pictures from the inside of the box in the Gallery.
      King29 refers.

      http://tf4m.com/nggallery/page-153/album-21/gallery-192

      The box does not contain any tuning devices yet – it will eventually do so for the other modes of operation.

      The resonance adjustments and matching are completely separate for the main purpose of the antenna – the vertical mode for 160m.

      For the vertical mode both vertical wires are tied together and the elevated radials are also tied together. The antenna is resonant on 1832kHz and R is matched with a UNUN transformer at the feedpoint. Later, the antenna will be fed in Differential Mode instead of Common Mode and will then work as a Dipole. Matching will then be performed with either a capacitor or an inductor between the vertical wires at a high impedance. (The antenna is also very close to resonance in Differential Mode). The UNUN transformer takes care of DC conductivity to ground.

      The stand-off insulators will be used later to enable connections to be made for measuring current in both vertical wires and each of the elevated radial wires in addition to enabling relay control band/mode switching and carry remote metering signals to the shack.

      The coil of wires seen to the back of the false bottom in the feedpoint box is 8 conductors of control wiring that goes all the way to the shack. I am aware that these wires may be too close to the antenna wires, this will be corrected soonest along with a general tidying up inside the feedpoint box.

      73
      Thor

  • Nigel G3TXF

    Hello Thor,

    Looks fantastic! In which direction is the immediate sea take-off? It’s hard to get a sense of scale in your photos without a person standing there! What are the dimensions of the vertical sections, the horizontal top sections and the horizontal radials?
    73 – Nigel G3TXF

    • http://tf4m.com TF4M

      hello Nigel,

      broadside to the antenna looking at the sea behind it is looking more or less due East.

      The antenna has a Salt Water propagation path for more than 180° east of a North/South line.

      We think that the ground near the antenna to the west is soaked with sea water and that should give a reasonable signal to the west, but that remains to be seen.

      Due to the extremely low angle of radiation, I do not even expect to have a strong signal for local signals, like for example EU.

      It is hard to get a photo of the antenna even with a super wide angle lens :-)

      The pole itself is 27m tall, weighs 3 tonnes, has a diameter of 50cm at the platform and 36cm at the very top. It was sunk 2.5m into solid rock. And is guyed in three directions. The guy anchor out in the sea was made by breaking a 2m deep hole into the solid rock and then filling up the hole with 2cubic meters of concrete, weighing around 5 tonnes.

      The working platform is at 3.5m, with the feedpoint box 115cm above that. The insulators are 1 meter in length and weigh around 30kg each.

      The vertical antenna wires measure 18.6m, the top loading radials – current sinks – are close to 23m and the elevated radials – the bottom current sinks – are 33.1m long.

      I estimate the strain on the antenna wires to be around 100-200kg, the weakest wire in the system has a breaking strength of around 1000kg, most of the construction can handle considerably more strain.
      Some earlier photos show me climbing the King during the construction, those photos demonstrate the scale of things quite well.

      The Arctic King is a serious antenna for a serious band.

      73
      Thor

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