top of page

Polar Research vessel Oden gets a ZachTek WSPR transmitter.

Updated: Jul 4, 2019

WSPR is a great way to explore and test a wide range of stuff in our wonderful radio hobby.

Although I guess most of us use WSPR casually with no real intent behind it most of the time, we occasionally use it for real useful things like to find out if a new antenna is better or worse than an existing one by comparing it's WSPR spots and distances.

I find that kind of test-and-research aspect of WSPR to be a really interesting and exciting part of our hobby.

Because of that I was really intrigued when I got an order for a WSPR Desktop transmitter from someone working in a place were they do actual research.


I was contacted by Lars Lehnert - call sign SA2LLL in the spring when he inquired about purchasing a Desktop unit to be used on board he Swedish Ice breaker and research vessel “Oden”.

He ended up inviting me to come aboard and checkout his work place.

During the tour of Oden I learned a lot of what is going on there and got a few photos and impressions with me back home so I thought I share it with you my reader as I suspect you might find this interesting as well.


Oden is a Ice breaker that was built in the 80ies with polar research operation in mind at the time it was designed and because of that it is uniquely designed to handle these dual roles.

Technology on board.

Lars handles most of the technical stuff on Oden from radios to computers and research equipment. The technical equipment keeps him very busy while they are out on an expedition but he still finds time to work a bit of Amateur radio every now and then with his HF radio.

He also had some existing WSPR equipment that he wanted to replace with with my WSPR Desktop transmitter.

He intended to run the WSPR transmitter more or less continuously and do band hopping between the four bands 40m,30m,20 and 17m.

One of the first thing that struck me when I got on board was the amount of radio technology they were using.

It is truly amazing and as you can see in my photos below the amount of antennas is mind boggling!

I have to confess my mind started to race thinking of all of the equipment that could be interfered with if the output of my transmitter was not clean enough.

The WSPR TX Desktop and it's design focus of clean output.

It is in environments like this that the heavy output filtering of the Desktop WSPR transmitter really is useful.

The Desktop transmitter besides having at least 50dB of overtone suppression (in some cases/bands the suppression can exceed 60db) also employ an extra VHF low pass filter that suppress the far away overtones in the VHF and UHF range.

This extra filter is needed because of a common imperfection in standard low pass filters that is used to filter output amplifiers.

This imperfection makes the overtone suppression to start to roll off in their effectiveness when we get far away from the design frequency.

I noticed this effect when measuring the filters in early prototypes.

I then decided that the Desktop model witch is the “flagship” model needs to have an extra set of filters to kill of these frequencies effectively even-though the regulatory standards don't require it.

I often curse myself for that decisions when I have to wind the toridal cores for this filter as it is an extra step that takes time in the build process.

But boy was I happy to have made that decision when I was onboard Oden and saw the radio environment it would operate in!

Integration of the WSPR transmitter to an antenna tuner.

Lars had mounted the ZachTek WSPR Desktop transmitter in a rack cabinet that sits in a shipping container on the starboard deck.

The antenna is a end feed wire that is strung up as diagonally up to a railing on the upper deck some 20 meter away.

He had an existing antenna tuner that was used to tune the antenna but one complication was that it was not an auto tuner, e.g it did not automatically tune as needed, you needed to press a button on the front panel to make it tune anew frequency.

To solve this problem I ended up building a small integration board that we put inside the tuner together on a second visit. Here is a photo of it while the tuner is opened up and we do a test run before putting stuff inside the box.

In the end everything worked perfectly and Oden is now on the way to Greenland while creating lots of WSPR spots worldwide from the 0.3W transmitter that transmits on four bands.

Here is a screen shot of 24 hours of 20m WSPR spots while Oden was under way.

The red line is added by me to show the path it has taken from Sweden out on the Atlantic.

The advantage of using GPS for the WSPR position report in all ZachTek WSPR transmitters.

The fact that my WSPR transmitters updates the position from GPS before every transmission is a great benefit in this application as we can use the WSPR transmissions as a position tracker to follow the ship as it makes it way.

The four letter Maidenhead limitation in a standard WSPR transmission can be seen as the grid squares are pretty big but regardless of that one can easily see the route it is following.

Here are some pictures and more information on the equipment on board.

Seen from the port side in Helsingborg harbor. (short Video, click to start it)

Lets starts with a few pictures from the bridge.

The Bridge.

I was expecting more dials and levers but I guess that is an old view of how a ship is controlled.

It is computers nowadays that handles that like most of the stuff in our society. Although they still “talk” to the old industrial control system that is doing the actual control at the lower level. So no big problem if a computer would hang or act up.

There is still a lot of serial communication at the heart of many of the systems Lars told me. RS232, RS485 and so on.

They run Ethernet in many different networks trough out the ship and to interface with the industrial control system that is serial based they transport much serial traffic over Ethernet and then convert to serial whenever needed

Sonar station on the bridge.

The sonar equipment is really advanced and can produce many types of data of the sea and seabed below it. One result of their sonar operations is underwater maps.

There was a picture hanging next to the sonar operators station that I thought I had to include.

I was told that their equipment would produce other types of images but not exactly this kind.

Flight station on the bridge.

The next photo is taken where the person responsible for flight operations has his station.

He operates VHF Flight radios and outside his window is the Heli-pad were they operate a couple of helicopters. This person is also a meteorologist.

View from the flight operations window towards the aft, showing part of teh Helipad. The helipad would have two helicopters on the upcoming expedition so not much room for errors when landing and taking off I would imagine or you would hit the parked one.

Outside, antennas, antennas, antennas

Moving out on the deck we are meet with antennas galore!

They had a bewildering array of antennas that I had a lot of fun going over with Lars, so much cool technology!

You see two radars, Satellite links, VHF antennas etc.

Four stacked VHF Antennas, I don’t know if they were for Air or Sea communication.

They had a bunch of fold-able verticals on the forward deck. You can see one that is folded across the deck towards the camera. They must have been at least 7 to 10m long so I guess they were part of the old HF radio network. I counted four of these fold-able antennas at the forward deck.

A small sample of the “Antenna forest” as seen on the Starboard railing.

The Antenna that is being used for Lars WSPR transmission is a wire that can be somewhat hard to see in this picture. I have drawn a red line next to it so you can make it out.

It is strung from a corner of the cargo container up to a railing on the top deck.

It is sloping at about a 30 degree angle and is around 20 meters long.

The ground plane made of the steel ship and the ocean is the best ground plane you can ask for and is probably a big part of the great performance he gets out of his transmission even though the antenna itself is quite modest.

Here is a picture inside the container that holds the WSPR transmitter.

This space will be shared by Lars and other expeditions member when they are underway.

Not visible behind the camera is a rack cabinet that holds the WSPR transmitter and antenna tuner.

(Note the string on the chairs, this is a ship, everything loose has to be secured )

One of the many cranes. This emplacements were originally built to house desk guns or canons but they were never fitted Lars told me.

Most of the equipment is stored in regular shipping containers. They do that because their operation changes so much between expeditions.

This gives them an easy way to rearrange depending on the particular operation going on at the moment.

The surprising thing for me was that even things you might consider permanent fixtures were housed inside containers. One such example was this.

Lars opened this container on the aft deck to show me…

This heavy winch used to tow large vessels that found it hard to move in newly broken up ice. Oden would then break the ice and tow the other vessel at the same time.

The tow-line was surprisingly thin and light weight. It was designed so it floated on the water Lars told me.

Not your average tow-line I guess, probably expensive high-tech stuff.

Most of the stuff are so specialized at this place that you cant really make out what is going on just by looking at it.

Can you guess what this is ?

A steel wire, right?

Yes, it is the steel cable they use to lower the water sampling equipment down in the ocean down to several kilometers of depth.

But it is also a coax cable!

The coax runs both power and signals in both directions.

The power is used for measurement equipment and to open and close valves at different depth to take samples.

It also sends signals down to control everything and the equipment down in the water sends live measurements data up to the ship on the same cable. I guess we do not want to know what the price per meter is on that coax :-)

The water sampling equipment.

Lars is demonstrating the valves on the tubes.

Each of the twenty four tubes can be opened and closed by timer or remote control to take samples at set intervals/depth as the entire cage is being lowered.

This water is partially analyzed in real time while in the water. Full analyzes can then be performed onboard or at shore when the expedition is back home again.


Moving to the inside we see the cafeteria/mess

The small pub.

Peeking in to a standard cabin.

Lars “office” and one of the many equipment rooms. It might be called the server room for lack of a better word.

Lars in front of one of the many computers rack strewn around the ship. This one handles incoming high-res digital satellite weather images if I remember correctly.

Closing words

I got this picture form Lars and I just love the helicopter perspective from an arctic expeditions. I thought I share it here as well as it such a great photo.

When I was a kid we used to go out to the frozen ocean in the winter and jump between ice sheets.

We did this for fun and to show off, sometimes we got home wet and cold.

It seems adults can do that as well and get paid for it. :)

I learned quite a bit from speaking with Lars. One thing I learned is that while the South Pole has this big bedrock under the Ice – there is no land at all at the the north pole!

There is just ice.

Oden can actually travel right up to North Pole just by going north and breaking up the Ice until they arrive!

I had a really good time on board and I could have spent hours talking about all the different systems and how they operated. As a former IT manager I know what it takes to handle complicated interconnected machinery and Lars and his staff for sure had their hands full on Oden.

Lars was really friendly and easy to get to know and a great host.

I left thinking that he had a great workplace, so much complicated stuff to tinker with, just lovely :-)

It turned out that in an earlier employment he had he worked down in the German research station Neumayer III on the South pole witch was a bit of synchronicity because I remember being fascinated by the spots in the Antarctic a couple of years ago when I put my first WSPR transmitter prototype on the air.

First I thought it was someone that had the wrong Maidenhead numbers in their computers but after a bit of research I found out it was the German research station that has starting running WSPR down there.

Now it turns out Lars had been down there and knew of their operations and thought we should give them a bit of friendly competition on the WSPR side from the Swedish research station up here in the north.

I of course agree with him wholeheartedly! :-)

If possible I will see if we can operate some more stuff and bands in future campaigns and I already promised some free receivers in the name of Swedish research, hmm have to build a few more I think.

We also briefly talked of flying a WSPR transmitter on one of their helicopters if/when they were doing cargo lift operations, hmm let me think how we could do that, if we.....

OK all that fun stuff have to wait I'm afraid!

I have to build some more WSPW desktop transmitters now. So back to work:-)

A big thank you goes out to Lars and I will close by wishing all my other customers and readers a great summer!



PS About Lars:

DS About Oden:

1,010 views1 comment

Recent Posts

See All

1 Comment

Donald Giles
Donald Giles
Jul 04, 2019

Thanks for posting this very interesting article, Harry. We went to Antarctica on an Ex-Soviet Union ice breaker that had been converted for touring use. South America to the Falklands. Then to So. Georgia Is and down to the ice cap and back to the tip of South America. Quark was the company that provides these trips. (Norway company, I think.)

I will look for SA2LLL on the DxPlorer or WSPRNet websites.

bottom of page