Currently viewing the tag: "160M"

The Arctic King adjusted for resonance

By On · Leave a Comment · In Amateur Radio

The resonance of the Arctic King was made slightly high to enable accurate adjustments of system resonance to be made at the feedpoint.

A small choke was inserted in series with the elevated radials with the resulting SWR curve shown.

Resonance is adjusted completely separately from matching the resulting resistance (R) which is done with a 50 ohm to 12.5 ohm UNUN transformer.

The Radiation Resistance at resonance is 17.5 ohms (+/- 0.5ohms), which accounts for the slight SWR (1.4:1 at feed point) at resonance.

Modelling gives approximately 75% radiating efficiency and less than 1dB in ground losses.

High Tide

By On · Leave a Comment · In Amateur Radio

The great Arctic King is built right on the edge of the sea.

This accounts for his extremely strong signal and low angle of radiation towards more than half of the horizon.

In addition, the salt water impregnates the ground around the King and ensures excellent ground conductivity and very low ground losses.

I would like to clarify that the Arctic King is only used for transmitting – I receive with an array of Beverage antennas ranging from 170 meters to 400 meters long in various directions.

I would also like to clarify that the downward angles of the top radial wires and the in-land angle as well, were dictated by the shape of the small peninsula that the Arctic King is built on and on the availability of large wooden poles.

Slightly better performance would have resulted if it had been possible to have the top radials horizontal and in-line.

Such poles are not easy to come by in Iceland, in fact the King – the 27m pole – is the largest pole in Iceland.

The Beverage antenna pointing towards Japan is the shortest Beverage in my arsenal – 170 meters long.

I intend to build a larger Beverage towards Japan to decrease the beam width and reduce the noise level even further.

160 meters at TF4M – 07 November 2009

By On · 2 Comments · In Amateur Radio

Today was not spectacular.

I heard JA7OEM while still in broad daylight and worked him on the first call.

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Later I spent a long time listening for FK8CP who was barely readable today and then I called CQ for a while.

The band was quite noisy and some Russian contest caused a bit of QRM across the band…

I have observed that a lot of the weekend warriors have limited receive capability.

They come on a busy frequency and immediately start calling CQ and it is quite obvious that they are most likely using their transmit antenna to receive with…it´s quite sad really.

This is the main reason that I would really like to see 160 meters free of contesting – except for the Stew Perry, of course….  and free of SSB too, while I´m at it.

Nevertheless, a few JA stations were added to the log, some incredibly weak signals which were quite difficult to copy, I have a feeling that my receive antenna system is being tested with QRP signals from Japan… :-)

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First !! QSO with 9M2AX !

By On · Leave a Comment · In Amateur Radio

Today there is a light breeze and I took some photos of the King.

I called CQ on 160 meters between 1700 and 1800 local time, still in daylight and was called by 9M2AX and we had the first QSO between West Malaysia and Iceland on Top Band to the best of my knowledge.

I was also called by Jack, VE1ZZ and 24 QSOs were made with Japan during this fine hour.

One or more  of the JA stations was QRP.

You may listen to the contacts:

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Kyo, JR9OPJ made a recording of our QSO

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I later called CQ between 1945 and 2051 leading up to JA sunrise with another 54 JA stations being worked for a total of 78 JA stations worked in one day.

Considering that working Japan from Iceland on 160 meters was considered impossible until I built my antennas, I am quite pleased.

The highlight of the evening was when VK6ANC called immediately followed by VK6VY.

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JA3FYC who worked me with only 5 Watts, sent me a recording of the QSO

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I would like stations who call me using QRP to understand that I do not log their calls with /QRP.

I would also prefer they do not indicate QRP with their call signs as this makes things harder than necessary.

It is difficult enough to pull the call signs out of the noise, without the added complexity of /QRP, when stations call with low power.

All recordings on my website may be downloaded if desired from tf4m.com/audio

Top Band 05 November 2009

By On · 3 Comments · In Amateur Radio

Conditions today have been poor.  No trace of TX3A either on 160 meters or on 80 meters.

I did call CQ on 160 meters with only a few JA stations being added to the log.

The band was very noisy which is unusual here, as can be heard in the recording.

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The Arctic King proves his mettle in battle

By On · 3 Comments · In Amateur Radio

The TX3A Chesterfield Islands DXpedition is QRV.

They were listening for JA below 1825 with a massive JA pile up which I could hear well and above 1825 for everyone else, but I was not hearing the EU and NA stations well.

I heard ON4UN and GM3POI calling in the pileup – those two have some of the strongest signals out of Europe, but I was not really able to find out where TX3A was listening or to discern his pattern of listening.

So I did the smart thing, I joined the JA pile up and I made the QSO in less than 5 minutes !

I can imagine that the  JA wall must have been MASSIVE at TX3A.

I could sense that TX3A did not really believe that TF4M was for real !

The Arctic King rules the North !

Of course, the on-line logs will determine whether or not I am in the log.

Update: The TX3A on-line log confirms that I am in the log.

QSO with TF4M in the log

QSO with TF4M in the log

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The Arctic King on fire

By On · 2 Comments · In Amateur Radio

Initial testing indicated a problem with the King.   My Emtron DX-3 amplifier would fault above a power level of approximately 700W.

I fired up the Harris KW amplifier and was able to determine that there was a problem.

Inspection of the feedpoint box showed that the antenna wires had made near contact with the control wires and there had been a small fire inside the box.

I dressed all leads and replaced coax jumpers to the box and between the isolation transfomer and the  UNUN transformer for good measure, with freshly made new cable.

I sealed the feedpoint box for the winter and now everything works properly.

I think conditions are poor now, even so the Arctic King provided me with 70 QSOs to Japan and one QSO to Australia on the first day of operation.

I am amazed to put it mildly.

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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Nearly there

By On · Leave a Comment · In Amateur Radio

I lowered the attachment points of the elevated radials by 50cm.   This was done to increase the distance between wires and the environment.

To accomplish this, I had to drive 70km to the nearest hardware store to buy two 16mm nuts which I was unable to find in the workshop.

The battery in my cordless drill died during the drilling of the King, I managed to borrow a battery and continue the work.

My hacksaw blade was dull as well, and once I gave up using it and went home to get a new blade, everything went well.

It took me 4 hours to install the eye bolts for the radials…

I measured the antenna with my CIA HF antenna analyzer at the feedpoint and the point of lowest SWR and X was now close to 1770kHz.   Removing 1 meter from each end of the elevated radials resulted in an increase to 1793kHz and by this time darkness and driving rain was upon me.

I hope to finish the resonance adjustments tomorrow and perhaps install the big insulators on the radials the day after, weather permitting.

It´s very close now, this is getting exciting :-)

I called CQ on a rather noisy band using about 100 Watts only and was called by several stations which were barely audible with my Beverage antenna system.

I then answered OZ8ABE´s  CQ after reducing power to around 5W.   He came right back to me and gave a 599 report, which was confirmed during the QSO.

This is  a completely new experience for me on Top Band and it indicates that the King radiates well.

Once the antenna has been adjusted for resonance and low SWR it will be possible to run full power to it.

I would be very interested in comments on my transmitted signal.

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