December 31, 2018

A magical morning with SAQ Grimeton Radio

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I've been a radio enthusiast since the early 1980s, but it wasn't until recently that I finally got myself a receiver and antenna suitable for listening to VLF (3-30 kHz) (see my earlier blog posting here).

One of my goals with the new VLF setup was to receive one of the special CW transmissions on 17.2 kHz from historical radio station SAQ Grimeton in Sweden.

Grimeton Radio was built during the years 1922-1924 to provide a "longwave" wireless telegraphy transmitting and receiving station for transatlantic telegram traffic with the United States. The first transmitter used was a VLF machine transmitter invented and designed by Swedish engineer Ernst Alexanderson. Grimeton Radio went on the air in December 1924 with the callsign SAQ. Initially transmissions were done on the frequency of 16.1 kHz but this was soon changed to 17.2 kHz.

The Alexanderson alternator transmitter at Grimeton Radio (source)

After some years, new technology had made the Alexanderson machine transmitter obsolete for its original purpose; by the 1930s transatlantic communication had gradually started to switch to shortwave, and vacuum tube shortwave transmitters were used instead.  The Alexanderson transmitter was still used however to communicate on VLF with submerged submarines, and wasn't  decommissioned until the 1990s. Luckily the complete site of Grimeton Radio, including the original VLF machine transmitter, has been preserved as a historical monument. In 2004 the radio station was added to UNESCO's List of World Heritage Sites.

Like mentioned earlier, the original VLF machine transmitter at Grimeton Radio was designed by Swedish engineer Ernst Alexanderson. It consisted of an alternating-current generator (the so called Alexanderson alternator) driven by an electrical motor through a speed-increasing gearbox. When driven at high speed at the correct RPM, the alternator generates a signal on 17.2 kHz. Yes, this means that RF is generated without any electronic parts (like tubes or transistors) involved at all!
Although not in regular use anymore, two or three times a year on special days a CW message is transmitted by Grimeton Radio using this very same historical Alexanderson alternator transmitter!

Traditionally, one of the special transmissions is done in the morning of Christmas Eve, and so was the case this year. And I was extremely happy to manage to catch it! For the first time I was listening to this special station, to a Morse Code transmission generated by a historical, pre-electronic transmitter, the only one of its kind remaining! And on one of the most beautiful and magical days of the year! Goose bumps!

Grimeton Radion at  - 6ºC on the morning of Christmas Eve 2018 (source)

The signals were picked up at PA7MDJ with an SDRPlay RSP1A receiver and a MegActiv MA305FT E-field probe antenna. Below on my SoundCloud account you can listen to the recording I made this beautiful Christmas Eve morning, December 24th, 2018.

The transcript of the received Morse Code message reads as follows:

ON 17.2 KHZ =

The message was preceded by a "VVV VVV VVV DE SAQ SAQ SAQ" loop.

In 2003 I visited the Grimeton Radio site to look for a geocache (one of my other hobbies), unfortunately without the possibility to take a look inside the transmitter building, but that's another story.

See also:  - Video made at Grimeton Radio during the special Christmas Eve 2018 transmission

November 30, 2018

November 29, 2018

CQ World Wide DX Contest QRP Style!

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In the first years of my ham career, I used to be quite an avid "search and pounce" contester, not really for the competitive element, but for the opportunity the various contests offered me to add new DXCCs, US States, islands and other interesting locales to the logbook. The solar activity was still at its peak, and oh the feast it was, putting in the log one new DXCC after the other! I remember 10m bustling with activity and me feeling like a kid in a candy store!

Nowadays, I'm not the avid contester I once was. Most contests nowadays bring nothing new to me. Still there are some contests that I stay at home for though, they are the IOTA Contest and the CW editions of CQ World Wide DX and CQ WPX contests.

Last weekend was the weekend of the CQ WW DX CW contest. I was participating with my usual setup with 100 Watts and a HyEndFed 10/20/40 wire antenna, and worked some nice new stations on 40m and 20m including PY0F on Fernando de Noronha and PZ5T in Suriname. But after a while the search and pounce just got boring. I've worked the US and Caribbean stations on 40m before, and it just doesn't have the magic it once had. At one point, to bring back some excitement, I decided to continue QRP.

More and more these days the callsign PA7MDJ/QRP can be heard in the "ether". Some time ago I became a member of QRP ARCI, and recently I also bought an LNR Precision Mountain Topper MTR-3B transceiver. The MTR-3B is a small, lightweight, 40/30/20m CW-only QRP-transceiver, originally designed by famous QRPer Steve Weber KD1JV. It's really a wonderful little high-performance QRP rig, and it will replace my much heavier Yaesu FT-817ND on future SOTA activations.

So, I left the shack and instead comfortably settled on the couch with my Mountain Topper, and continued my participation in the CQ WW contest. The couch set-up was complemented with a Palm Pico Paddle, and a small 9.9V 2100mAh LiFePo4 battery to power the MTR-3B. The rig was connected to the same HyEndFed antenna mentioned above. With the MTR-3B connected to 9.9 V it delivers a power to the antenna of approximately 2.5 to 3 Watts. I wondered what I would be able to do in the contest with this little power.

The QRP "Couch set-up"

As expected I was easily working some European and Russian stations on 40m, then much to my surprise succesfull 40m contacts followed with entities like Asiatic Russia, the Canary Islands, Algeria, and Morocco. Then at one point on 40m I managed to work the first US East Coast station! And more followed, New York, New Hampshire, Pennsylvania, North Carolina, Florida! Unbelievable, I'm sitting on my couch with a transceiver about the size of a deck of playing cards working the US on 40m with less than 3 Watts on a wire antenna! Suddenly the magic was back!

On 20m the next day with the same QRP "couch set up" I also managed to work Senegal on 20m and Kazakhstan on 40m!

This was an unbelievable succes, and QRP has brought back the excitement in contesting! This time I just sent in a checklog, but next time I might consider entering the contest in the QRP category.

November 28, 2018

How low can you go? Explorations of the MF, LF, and VLF bands.

Last edited: 01.12.2018

I've always been fascinated by ELF, VLF and the lower part of LF, and both the man-made signals and Natural Radio emissions occurring on these bands have always intrigued me. I never had a suitable receiver and antenna for this part of the RF spectrum though.

This changed when some time ago I bought an RSP1A SDR-receiver, and more recently a MegActiv MA305FT E-field probe. This receiver / antenna combination for the first time enabled me to seriously explore the mysterious realm below 100 kHz, all the way down to about 9 kHz (the lower limit of the frequency range of the MA305FT)!

It's really fascinating listening for the first time to the various Time Signal Stations and to the transmissions of the numerous naval stations using these low frequencies to communicate with submerged submarines. On VLF, radio signals are able to penetrate seawater to a depth of up to about 40 metres, depending on the salinity of the water (contrary to higher frequencies which do not penetrate seawater to any significant depth). On ELF the signals can penetrate even deeper, and the Russians are operating a transmitter known as Zevs near Murmansk to communicate with their submarines on a frequency of 82 Hz (yes, Hz, not kHz!). A similar system is (or was?) also in use by the United States on 76 Hz.

The Norviken VLF transmitter (callsign JXN) in Norway can be heard on 16.4 kHz. The station is used to transmit messages to submerged submarines. VLF antennas are huge; the antenna of JXN is made up of three wires spun between two mountains and spanning a distance of over 2 km! (source)

The MegActiv MA305FT E-field probe is manufactured by NTi in southern Germany close to the Swiss border. It's an active antenna of the popular so-called Mini Whip type. Probably the most well known mini whip is the original Mini Whip designed by PA0RDT, and most other mini whip designs are more or less based on the same principal.
Some time ago I already bought a mini whip kit from Van Dijken Electronica, but I never got round to building it. Then, while visiting the yearly VERON Ham Radio Convention in Zwolle early November, I noticed the stand of Bonito with various active E-field (mini whip) and H-field (loop) type antennas for sale. Bonito is closely involved in the designing and testing of the various antennas made by NTi. The MegActiv MA305FT caught my eye, was looking very well built, and was offered for 20 euros below the normal price. I checked the internet and found that the antenna in various reviews was scoring very well. I decided to buy one.

I bought the MA305FT mainly for exploring the VLF, LF, and MF bands, and this is where the antenna really shines, as you'll see later on.

At the University of Twente they have a mini whip antenna in use for their WebSDR. Their mini whip is performing extremely well, and their WSPR reception has become the high standard reference for me for doing rx antenna evaluation. WSPR reception results can easily be compared by checking the spots of the University of Twente (callsign PI4THT) on When doing WSPR reception comparisons, on all bands from LF through to HF 20m (I never checked the higher bands) the mini whip of PI4THT always outperforms my HyEndFed 10/20/40 sloper wire antenna.

When I got home from Zwolle I immediately set up the MegActiv in the back of my small yard at a height of about 3 metres on a PVC pipe placed on a large tripod. The active antenna is powered over the coax feeding cable with the special coaxial power inserter that comes with the antenna. The inserter can be powered in several ways, including from for instance a laptop USB port. The antenna / inserter can be fed with a power source ranging from 5 to 15 Volts DC. I tried powering it with several of the 5 V power banks that I have, but all shut down after a while due to the power inserter drawing very little current and the powerbank thinking nothing is plugged in ( I recently saw a little device for sale at SOTABEAMS which in such a situation will prevent a powerbank from shutting down, and of course such a "keep alive load" could also be homebrewed very easily).

The MegActiv MA305FT active E-field probe. Frequency range 9 kHz - 300 MHz.

Once everything was set up, one of the first things I did was monitoring the 630m MF WSPR frequency (474.2 kHz dial). This looked very promising; the SNRs of the signals received often were not far below of the spots made by PI4THT, sometimes even better! The next day on November 5th I managed to receive the 5 Watt WSPR signal of AA1A in Massachusetts, USA! With this I really outperformed PI4THT, as no MF WSPR spots for US stations were made at all that day at the University of Twente!

Reception of the 630m WSPR signal of AA1A with the RSP1A and the MegActiv antenna

On VLF and the lower part of LF a lot of signals were received with excellent strength, mostly time signal stations and the naval stations mentioned earlier, but also various telecontrol signals and for example the RTTY weather reports from the Deutsche Wetterdienst DDH47 on 147.30 kHz.
In the 1990s I used to be an avid LF NDB DXer, and I really enjoyed rediscovering this part of the radio hobby wth the RSP1A and the  MegActiv. New to me in the field of NDB DXing are the DGPS stations, many of them actually being the old closed down maritime NDBs. I also had excellent reception of various coastal stations with NAVTEX weather and navigational warnings on 518 kHz, and I see some real DX potential here for the dark winter months. With MultiPSK I was able to decode the DDH47, EFR telecontrol, DGPS, and NAVTEX signals.

I'm looking forward to the next Morse transmission of the historical station SAQ Grimeton in Sweden on 17.2 kHz which I hopefully will be able to pick up with the setup described in this blog. The last time I tried it with a wire antenna and I failed. SAQ Grimeton was one of the reasons why I really wanted to improve VLF reception.

Reception with the MegActiv MA305FT on HF so far has been a little disappointing. I expected the reception on HF with the MA305FT at least to be on par with my HyEndFed, but on 40 and 20m WSPR and FT8 the HyEndFed was the clear winner. Compared to 40 and 20m WSPR reception of PI4THT the MegActiv just could not compete at all.
This doesn't mean the MA305FT can't do better on HF though. It could all be a matter of finding the best location and setup for the antenna. To work properly a mini whip type antenna should have the coax shield close to the antenna connected to an earth electrode. I don't have such an earth electrode available yet. At PI4THT they don't have an earth electrode, but the roof on which their mini whip is located contains a lot of metal which serves as the antenna's earth. I might install an earth electrode later on, and more experiments are needed to say something meaningful about the performance of the MegActiv on HF.

The MA305FT opened up. With a jumper an FM broadcast band notch filter can be switched in.

I've heard some people say that an SDR and an active antenna don't match very well, due to the antenna causing overloading very easily. Also I've heard people say that an active antenne like the mini whip is very prone to picking up the omnipresent electrical noise of an urban surrounding. I didn't notice any of this being much worse than with the other antennas I have in use though.

With the recent exploration of the RF spectrum basement, a new radio hobby door has opened up, and I got inspired to continue with more VLF, LF, and MF experiments. I would like to experiment with using special software and a PC soundcard as VLF receiver  (a soundcard with a sample rate of 48 kHz can receive radio signals up to 24 kHz*). One day I'll also built the mini whip kit and see how it compares to the MegActiv.
And who knows, maybe the future sees me transmitting WSPR on 630m MF myself, using the MF Solutions transmit converter described here and here (in combination with my QRP Labs U3S), and an earth-electrode antenna as in use by G3XBM and as described here.

And still the RF spectrum below 9 kHz and Natural Radio remains unexplored. Someday I will also buy or built myself a natural radio receiver.

* I was mistaken earlier and wrote 96 kHz, it should be of course 24 kHz.

See also:

November 16, 2018

Going Transatlantic on the Magic Band!

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On the 6m band at my QTH, an urban location, since a few years I have a lot of noise, making contacts on this band difficult to impossible, depending on the strength of the signals. Disappointed I already took down my 6m HB9CV antenna a long time ago.

Last summer however I decided to do some WSPR experiments on 6m with my QRP Labs U3S standalone WSPR transmitter. I wanted to see what Sporadic E (Es) could do for me, and where I would be heard with the less than 100 mW the U3S puts out on the Magic Band. On TX only, the noise I experienced on 6m would be no problem.
So, I built a simple 6m dipole wire antenna and put it up indoors in the attic. Amazingly, I was quite successful with it and managed to have my WSPR signals spotted all the way in Morocco (read more about it in my blog posts here and here)!

While the 6m dipole was there, why not use it to see if I can make some 6m FT8 contacts with it? With the noiseblanker of my transceiver, the pulsating noise could be reduced a bit, and with favourable Sporadic E conditions with the indoor dipole I was making 6m FT8 contacts all over Europe easily!

Over the summer I had seen the reports of European hams making long haul 6m FT8 contacts with Canada and the USA on days with good multi-hop Es conditions! Amazing, I thought!

July 22nd was such a day with good transatlantic multi-hop Es conditions, and with the indoor 6m dipole on 6m FT8 I saw many Europeans working Canadian and Stateside stations. Amazing! At one point I even started receiving US and Canadian stations myself! Amazing!
Ok, why not try calling one? I called VE1PZ over in Nova Scotia, Canada, and not much later I saw a red line appear with VE1PZ coming back to my call.Wow, I nearly fell off my chair; I was using only 25 Watts and a simple indoor dipole antenna! AMAZING! The conditions must have been outstanding! It was my first transatlantic 6m contact. Later that day I also managed to make a 6m FT8 contact with 9K2BM in Kuwait.

The contact with VE1PZ resulted in the wonderful QSL-card shown above and below. It will always be one of the most special contacts I ever made. Well, after all it's the Magic Band, and I must admit, although it still is not my favorite weak signal mode, also a little bit the Magic Mode, FT8 :-)

November 08, 2018

The National NC-183D receiver - You can't log 'em if you can't hear 'em!

Last edited: 02.01.2019

On October 27th I set out on a long car trip to the southern part of the Netherlands, to Roermond, to pick up this old beauty that I had bought at an online marketplace site. It's a National NC-183D general coverage / amateur band receiver from the 1950s. It's in perfect condition, both cosmetically and technically. Listening to the NC-183D is such a treat; CW, SSB, but especially the full and warm sound of AM broadcast stations! The AM sound is exceptionally good, and I believe no modern amateur receiver will ever be able to match it. The whole experience of using this old radio, visually, auditory, olfactory, to me it brings back the magic I felt when I started out as a radio hobbyist as a young teenager in the early 1980s. Finding a NC-183D outside of the United States is not a very common occasion.

I'm a sucker for old amateur rigs and communication receivers, but mostly I can resist the urge to buy them (so far I had been able to keep the collection constrained to a Yaesu FTdx-100 transceiver and a Signal Corps BC-312-M receiver). But this one I really had to have. The predecessor of this particular model, the National NC-173, which in appearance is almost identical to the NC-183D, was used in 1947 by the two radiomen aboard the balsa raft of Thor Heyerdahl's legendary Kon-Tiki expedition across the Pacific. The photos and film footage I've seen of this radio in use aboard the raft had left an unerasable impression! See also my blog entry about amateur radio aboard the Kon-Tiki raft here.

With its 30 Kg the NC-183D definitely fits in the category "boat anchors" which vintage radio enthusiasts often affectionately like to call their old radios.The NC-183ND was manufactured by the National Company Inc. of Malden, Massachusetts, USA between 1952 and 1959. The radio's new price was about US$ 380, which at the time was about one fifth the price of a new car! 

I have some old QST magazines from the 1950s in my collection, and one of them (the October 1953 issue) contained this wonderful National advertisement for the NC-183D shown in the pictures below. Coincidentally this issue on page 31 also contains an article on "How To Tune S.S.B. on Any Receiver". SSB was a novelty in those days, and even though a receiver was equipped with a BFO for CW reception, getting a clear, intelligible SSB signal from the radios of this era wasn't as straightforward. As I found out with the NC-183D, and as suggested by the QST article, turning down the RF Gain does the trick!

Imagine the signals this radio might have picked up during its lifespan! Did it pick up the signals of the Sputnik-1 in 1957*? Did its owner listen to broadcast stations playing the first Rock and Roll songs? Did it hear amateur signals from countries that no longer exist? From countries across the Iron Curtain? The NC-183D grew up during an exciting time in world history, just imagine the endless possibilities of exciting signals this radio might have picked up....

Below you'll find a list of selected links to webpages containing more information about the National NC-183D. More will be added over time.

"You can't log 'em if you can't hear 'em! No matter what else a receiver does, it must pull ém in! And that's just what the NC-183D does!" is how National in 1953 advertised the radio, and amazingly this one after more than 60 years still does!

*The Sputnik-1 was the world's first artificial satellite. It was put in space by the Soviet Union and signalled the start of the "space race" between the US and the USSR. The Sputnik-1 transmitted a 1 Watt signal on 20.005 and 40.002 MHz. It could be easily picked up by amateur radio operators around the world. Even the US time signal station WWV halted its 20 MHz nighttime broadcasts to avoid interference to the Sputnik signal! Some more interesting links can be found below.

See also:

September 14, 2018

QSL card in the Spotlight: SV2ASP/A - Mount Athos

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I can't express just how incredibly happy I am with this wonderful QSL card from the legendary Monk Apollo of Mount Athos! I've written about the autonomous monastic state of Mount Athos before. Mount Athos forms a separate DXCC entity, and about the only chance of adding it to your list of DXCCs worked is Mount Athos resident and ham radio operator Monk Apollo. You can read more about it in my blog post here.

At least since I've been an amateur radio operator, Monk Apollo hasn't been very active on the ham bands, and when he is he's usually gone before you know it! And during those rare moments that Monk Apollo is QRV, the massive pile-ups that the elusive DXCC generates, make the chance of getting that QSO even slimmer.

But this summer, during the last weekend of my summer vacation, Monk Apollo suddenly and surprisingly spent a very large part of both the Saturday and Sunday making CW QSOs on the 20m band! If you still needed Mount Athos, this was your chance! It definitely was mine, and I took it! I was ecstatic when I finally succeeded in making that long dreamt of QSO with that wonderful, magical, mysterious, and elusive place! It was not only the thrill of working a new DXCC, but even more so of having my signals being picked up in magical Mount Athos, and of making a contact with the honourable and legendary Monk Apollo himself!

August 31, 2018

Recommended Website

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Wow, I really love this site by Julian W. OH8STN, and I wonder why I haven't heard about this site before. It's packed with information, innovative ideas, and inspirational videos for the off-grid, outdoor, and QRP radio operator. Go check it out:  HAM RADIO & OFF-GRID POWER -


August 30, 2018

QRP Shopping

Last edited: 11.11.2018

I'm a QRP enthusiast and every now and then I like to browse the various sites of vendors selling QRP stuff, to get some inspiration for a new QRP homebrew project, or to find that special QRP gadget to complement or perfect my QRP and outdoor radio setup. I'm always looking for smaller and lighter! Problem is that I always forget those URLs and vendor names (there are many).
So I've decided to compile this list of links, for myself, and for other QRP enthusiasts that happen to stumble across my blog site. Happy shopping!

Four State QRP Group  (of HI-PER-MITE CW AF filter fame)

QRPme  (of RockMite QRP CW transceiver fame)



QRP Labs  (of Ultimate3S WSPR transmitter and QCX QRP CW transceiver fame)

Kanga Products

EMTECH  (of ZM-2 antenna tuner fame)


QRP Club of New England (of NEScaf AF filter fame)

NorCal QRP Club

LNR Precision Inc.  (of Mountain Topper QRP CW transceiver fame)

KD1JV Designs (the famous Steve Weber of Appalachian Trail Sprint and Mountain Topper QRP CW transceivers fame)

Pacific Antenna


Palm Radio  (of Palm Mini / Pico Paddle fame)    new!

Lambdahalbe / Informationstechnik    new!

More links will be added to this list over time. If you have suggestions for sites to be added, just let me know, or post your links in a comment.

August 16, 2018

EME Conference 2018

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The 18th edition of the International EME Conference will be hosted by the Netherlands. It will take place on August 15-19 in Egmond aan Zee. Every two years the International EME Conference is the place to be to meet fellow "moonbounce" enthusiasts from all over the world.

It has always been my dream to one day make an EME contact, and a couple of years back my dream came true; with a low-budget moonbounce set-up (a single 10 el. yagi and 100 Watts) from my small backyard I managed to make two 2m EME contacts, one with I2FAK and one with KB8RQ. To me, EME is the ultimate DX, the ultimate in a ham's carreer.

So, I believe I'm entitled to say that I belong to the EME "incrowd". I will be attending the EME Conference on Saturday. I'm looking forward to meeting some of the EME experts and to learning more and being inspired during the various and numerous lectures.

The first International EME conference was held in New York City in 1966. Below a history of past editions in chronological order:

  • 1.    1966  New York City, USA
  • 2.    1968  Paramus, NJ, USA
  • 3.    1988  Thorn, Netherlands
  • 4.    1990  Trenton, NJ, USA
  • 5.    1992  Thorn, Netherlands
  • 6.    1994  Göteborg, Sweden
  • 7.    1996  Bowie, MD, USA
  • 8.    1998  Parigi, France
  • 9.    2000  Rio de Janeiro, Brazil
  • 10.  2002  Prague, Czech Republic
  • 11.  2004  Trenton, NJ, USA
  • 12.  2006  Würzburg, Germany
  • 13.  2008  Firenze, Italy
  • 14.  2010  Dallas, TX, USA
  • 15.  2012  Cambridge, UK
  • 16.  2014  Lannion, France
  • 17.  2016  Venice, Italy

For the local ham club I wrote a short article (sorry, only in Dutch) describing all the steps that led to the final result of my low-budget EME setup, and to the succesfull EME contacts I managed to make with it, hoping to inspire others to also try setting up a similar EME station. The article can be found here.

Below the QSL cards received for my EME contact with I2FAK and KB8RQ. Looking at them still fills me with pride!

See also: - The first Amateur Lunar tests and contacts (I love this site, check it out!)

August 07, 2018

Swedish icebreaker Oden and the mystery of SA2LLL/63

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This is the Swedish icebreaker Oden. Built in 1988 and originally used in winter time to keep open the shipping lanes of the Gulf of Bothnia, she was later modified to be used as a polar research vessel. The Oden has been on many expeditions both to the Arctic and the Antarctic, and she was the first non-nuclear surface vessel to reach the geographic North Pole! Seven more visits to the North Pole have followed since.

Currently the Oden is on a research expedition called Arctic Ocean 2018, a joint effort of the Swedish Polar Research Secretariat and the USA's National Science Foundation. At the beginning of August, the Oden left Longyearbyen, Svalbard and started the first part of the expedition to the north polar pack ice. At some point during the expedition, for the duration of about one month, the Oden will be moored at a large Arctic Ocean ice floe and will slowly drift with it towards the North Pole.

The good news for the ham community is that onboard the Oden is amateur radio operator Lars Lehnert SA2LLL (ex DL1LLL). According to his page and his special Facebook page, Lars will be active from the Oden with the special callsign 8S8ODEN, in PSK, SSB, and WSPR!

I noticed that at the end of July and on August 1st, Lars was already making WSPR spots from the Oden as SA2LLL/MM on the 20m band from grid JQ78tf (Longyearbyen, Svalbard) (Fig. 1). I was not aware of this, and unfortunately was not doing any 20m WSPRing during that time.

Fig. 1  Lars Lehnert SA2LLL/MM making spots on 20m WSPR from the Swedish icebreaker Oden in grid JQ78tf.

When I was doing a 20m WSPR monitoring-only session though on August 3rd, I did receive some WSPR transmissions from SA2LLL/63, three in total, all consistently on 14.097042 MHz and with a DT of around 4 seconds (which is unusually large) (Fig. 2). I have no doubt this was Lars WSPRing from the Oden in the Arctic Ocean, but I have no clue what the /63 stands for. My WSJT-X did not upload the spots to, or at the database were simply ignored, most likely due to the received messages not containing a grid locator.
I checked the database, but no SA2LLL/63 spots could be found at all made by any other listeners.

Fig. 2  PA7MDJ receiving SA2LLL/63 on 20m WSPR. Receiver and antenna used were an SDRPlay RSP1A and an EFHW wire antenna. Note the frequency and the unusual large DT!

Then some time later that same day I received what probably was the matching second part of the SA2LLL/63 compound WSPR message (Fig. 3). When transmitting a compound callsign in WSPR it will be done in a two-transmission sequence; one carries the callsign and dBm power level, and the other carries the grid locator. When both are received, the WSJT-X or WSPR software will match the two transmissions in the decode screen.

The grid received was JQ78tf, which, looking at the frequency and the fact that SA2LLL/MM already used this grid at the end of July / 1st of August I have no doubt this was also originating from the Oden (Fig. 3). Unfortunately my WSJT-X did not make the match with the SA2LLL/63 message part (probably a too long time between the last reception of the part containing the callsign and the second part containing the grid locator).

Fig. 3  PA7MDJ receiving the second part of the SA2LLL/63 compound message containing the grid locator. Note the frequency and the DT!

Strange thing is that on August 3rd the Oden according to the special Arctic Ocean 2018 web page was not in grid JQ78tf (Longyearbyen, Svalbard) anymore, but already was in another grid north of the Svalbard Archipelago (Fig. 4). It might be that Lars overlooked to update the grid locator (which is quite a hassle on a moving ship when not done automatically). What also puzzles me is why other monitoring stations (many of them equipped much better than I am) also failed to receive the complete matched compound transmissions (as shown by the lack of spots in the WSPRnet database).

Fig. 4  The position of the Oden on August 3rd, north of the Svalbard Archipelago.

Then I remembered that the official WSPR manual notes that when sending compound callsigns, an add-on suffix can be either a single letter or one or two digits. A single letter! So in WSPR TX the /MM add-on will not be possible! I started wondering if maybe the /MM add-on when transmitted would decode into /63.
I decided to do an experiment, and in the settings of my WSPR 2.0 program added /MM to my callsign. I let WSPR 2.0 do some TXing and with a virtual audio cable fed the audio to WSJT-X (please note, no actual RF transmitting was done!) And lo and behold, WSJT-X decoded the messages into PA7MDJ/63 (Fig. 5)! And also, WSJT-X failed to make a match between the two compound messages! I say no more, I guess the mystery is solved.

Fig. 5  The experiment with PA7MDJ/MM sent by WSPR 2.0 and decoded as PA7MDJ/63 in WSJT-X. No match between the two compound messages is made (normally with a match the dots in the < ... > part would be replaced by the callsign).

At PA7MDJ nothing has been heard from the Oden since August 3rd, but Lars mentions on the special 8S8ODEN Facebook page, that he can use the 8S8ODEN callsign as soon as they're in international waters. I'm now regularly monitoring 20m WSPR and anxiously await the special callsign to pop up in my WSJT-X decodes.

"Normal " satellite coverage (like INMARSAT) in the High Arctic is minimal to non-existent, and I guess any Facebook or other internet media updates from Lars during the expedition will be sporadic to none.

See also:

July 24, 2018

Stay tuned for HAARP WSPR transmissions!

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Ok, what are they up to at HAARP (the High Frequency Auroral Research Program in Gakona, Alaska)? Are they really going to do it? Some recent posts by HAARP Chief Scientist Chris Fallen KL3WX on Twitter (see below) suggest that they're really going to do some tests in WSPR mode during the summer research campaign coming up soon!
I like the thought of maybe being one of the initiators of these HAARP WSPR tests; I suggested using WSPR mode to Chris Fallen in a Twitter post long time ago, and I also suggested it in my blog post / open letter to Chris Fallen here.
I'm really excited about this news, and I'm really looking forward to catching some WSPR signals from HAARP soon.

During the last research campaign, in the spring of 2018, I was quite successful at receiving and identifying one of the HAARP transmissions. The observed odd off time of one of their transmissions on 9.500 MHz helped me identify with 100 percent certainty the received signal as coming from HAARP.

HAARP signal as received by PA7MDJ on 9.500 MHz on April 8th, 2018 made visible in Spectran and Argo which clearly shows the off time of 01:29:30 UTC, exactly as announced by Chris Fallen on Twitter (see below). This positively identifies the signal as coming from HAARP. Click to enlarge.

During one of their earlier campaigns I was already successful at receiving HAARP on 9.500 MHz, but then the observed off time of exactly at the hour left some room for doubt (although not much, see my blog post here).
The received HAARP signals consisted of a carrier only, and there was no other way to identify the signals than by observing the start / off times of the received signal and to see if they correspond to the announced start / off times. The HAARP WSPR signals without doubt will be a lot easier to identify.

If you're interested in my other blog entries about HAARP, take a look here.

July 16, 2018

Recommended reading

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Just some interesting articles I've recently discovered and that I'd like to share. One about the mystery of Long Delayed Echoes that every now and then are observed on the MF and HF bands, and one about Portable Amateur Radio in the 1960s and up until now.

The Five Most Likely Explanations for Long Delayed Echoes by Sverre Holm, LA3ZA, University of Oslo

Portable Amateur Radio, W7ZOI/7 by Wes Hayward, W7ZOI


Wes Hayward in 1967 operating W7ZOI/7 on the summit of Mt. Adams, Washington State (source)

Also make sure to check out Sverre Holm's excellent blog with lots of entries on QRP operation, Pixies, Altoid projects, Unusual HF propagation, and much more!

July 05, 2018

Magic Band Whispers - Morocco with 100 mW and an indoor dipole!

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Mission accomplished: my 100 mW WSPR signal was received via Sporadic E (Es) on 6m in Morocco! This was one of the goals I had set for this Es season for 6m WSPR (see also my blog entry of  May 17th). The transmitter and antenna used were a QRP Labs U3S and a simple homebrew indoor dipole in the attic for the 6m band!

CN8LI in Morocco hearing PA7MDJ

12 hours period of 6m WSPR reception at CN8LI

Morocco is my 70th DXCC reached with WSPR with 200 mW of power.

CN8LI keeps an interesting blog on

May 18, 2018

Yaesu YF-122C CW filter / QRP CW contact with the Faroe Islands

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I'd been looking into buying a narrow CW filter for my Yaesu FT-817nd rig for some time, but the high price (about € 130) for both the YF-122C (500 Hz) and YF-122CN (300 Hz) had been holding me back. But this week I got the opportunity to buy a used YF-122C filter for less than half the price of a new one. I couldn't let this offer go.

My Yaesu FT-817nd last summer on the summit of Pilatus mountain in Switzerland

Today the filter was delivered by the mailman. I spent about half an hour on installing the filter, and after some initial tests I must say it's working great! Installation of one of the optional filters into the FT-817nd is easy; just take out some screws, remove the rig's top case, and push the filter board onto the designated pins on the main board of the transceiver!

The 500 Hz filter will definitely make CW QSOs with the FT-817 a lot easier, and I'm all ready to do some more SOTA activations with it coming summer.

Before installation. The filter goes onto the main board in the designated free space opposite of the tuning knob.

After installation

After installation of the filter I made a nice CW contact with the FT-817 with OY1CT on the Faroe Islands. The contact was made as PA7MDJ/QRP on 20m using just 5 Watts and my HyEndFed 10/20/30 wire antenna. You can listen to the contact below (sorry for the background noises, please don't pay attention to them, hi). This contact was made with the 500 Hz filter activated.

And while talking about the FT-817, one site I always like to return to for more information about this popular QRP and backpack rig is "The KA7OEI FT-817 pages". Another interesting site is "K6XX's FT-817 page". If you're a FT-817(nd) owner these sites might be of interest to you as well.

May 17, 2018

6m Sporadic E and the Maldives on 20m (WSPR chatter 5)

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It's May and that means that the Sporadic E (Es) season is upon us. I've always been fascinated by this unusual radio propagation phenomenon, and I have fond memories for instance of the 1990s when I did a lot of VHF band I TV DXing, with Es during spring and summer enabling me to catch TV stations from all over Europe and sometimes even beyond.

For this Es season I had planned to do some 6m WSPRing with my QRP Labs U3S. So recently I quickly built the U3S 6m LPF kit that had been lying around for some time, and I also made a simple 6m dipole. And with simple I mean really simple; just some wire cut to resonance, some pvc pipe insulators, and lots of hot glue. The antenna is placed indoors in the attic.

The centre insulator of the simple indoor dipole made for 6m WSPR

With my U3S on the HF bands frequency drift never had been a real issue (mostly 0 on the lower bands, and mostly 0 to 1 or an occasional 2 Hz on the 20m band), but now on 6m the drift was considerable, mostly 4 Hz, probably making decodes impossible or difficult. But setting the "park mode frequency" to mode 2 and 150 MHz (to keep the U3S' DDS warm in between transmissions) cured the problem and reduced the drift down to 0 to 1 Hz.

The power of the U3S on 6m is less than on HF; on the "Magic band" I measured it puts out less than a 100 mW.

Es conditions so far haven't been great, and I've also noticed that there isn't really much of a "WSPR scene" on 6m  (which I find very strange, as 6m is really interesting to do WSPRing on to study the unusual and fascinating propagation phenomena of this band). Nevertheless, a couple of days ago my tiny 6m Es WSPR signals were spotted for the first time thanks to SV2HNH in Greece. On HF it wouldn't be that special, but now I was really excited about it.

SV2HNH hearing PA7MDJ on 6m

I will be WSPRing on 6m this Es season on and off. There's a very active monitoring station in Morocco (CN8LI), and for the remainder of the season I've set my goal to having my WSPR signals picked up by this station at least once.

Further exciting news is that my 200 mW WSPR signals were picked up on 20m by 8Q7HI on the Maldives, my 69th DXCC reached with 200 mW WSPR (see my WSPR DXCC list here). TX was my U3S, and the antenna used was a HyEndFed 10/20/40.

8Q7HI hearing PA7MDJ on 20m

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