November 24, 2019

Surf's Up!

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Excited to have my 200 mW WSPR signals picked up last weekend all the way on Hawaii! I was one of three Dutch stations to be heard by AI6VN/KH6 on 30m on the island of Maui that day. The other two Dutch stations were using 5 Watts. Hawaii is my 71st WSPR DXCC at 200 mW (see the complete list here).

I used my QRP Labs U3S transmitter and a homebrew indoor magnetic loop antenna (see also the blog entry here).


 




Maui, Hawaii (source)

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:

CQ CQ CQ DE SAQ SAQ SAQ =
THIS IS GRIMETON RADIO / SAQ
IN A TRANSMISSION USING THE ALEXANDERSON 200 KW ALTERNATOR
ON 17.2 KHZ =
WE WISH YOU ALL A MERRY CHRISTMAS AND A HAPPY NEW YEAR =
SIGNED: THE WORLD HERITAGE AT GRIMETON
AND THE ALEXANDER-GRIMETON VETERANRADIOS VAENNER ASSOCIATION AR =
FOR QSL INFO PLEASE READ OUR WEBSITE:
WWW.ALEXANDER.N.SE II WWW.ALEXANDER.N.SE =
DE SAQ SAQ SAQ SK

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:

https://www.youtube.com/watch?time_continue=2719&v=shqi43EV07c  - Video made at Grimeton Radio during the special Christmas Eve 2018 transmission
https://alexander.n.se/?lang=en
https://en.wikipedia.org/wiki/Grimeton_Radio_Station
http://whc.unesco.org/en/list/1134

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 WSPRnet.org. 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:

https://en.wikipedia.org/wiki/Very_low_frequency
https://en.wikipedia.org/wiki/Extremely_low_frequency
http://www.vlf.it/zevs/zevs.htm
https://en.wikipedia.org/wiki/Noviken_VLF_Transmitter 
https://www.fenu-radio.ch/en-index1.htm#MegActiv
https://www.vandijkenelektronica.eu/nl/57-antenne-s-en-antennebenodigdheden
http://websdr.ewi.utwente.nl:8901/
https://www.mwlist.org/vlf.php
https://www.efr.de/
https://en.wikipedia.org/wiki/Non-directional_beacon
https://en.wikipedia.org/wiki/Differential_GPS
https://en.wikipedia.org/wiki/Navtex
https://alexander.n.se/the-radio-station-saq-grimeton/saq-transmissions/?lang=en
http://www.472khz.org/
http://www.pa3fwm.nl/technotes/tn09d.html
http://www.pa3fwm.nl/technotes/tn07.html
http://dl1dbc.net/SAQ/Mwhip/pa0rdt-Mini-Whip.pdf
http://dl1dbc.net/SAQ/Mwhip/Article_pa0rdt-Mini-Whip_English.pdf

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:

https://people.ohio.edu/postr/bapix/NC-183D.htm
https://www.eham.net/reviews/detail/4423
https://www.radiomuseum.org/r/national_nc_183dnc183.html
http://bama.edebris.com/manuals/national/nc183d/
http://jvgavila.com/nc183d.htm
https://www.prismnet.com/~nielw/nat_list/nc183d.htm
http://www.radioing.com/museum/rx5.html

https://en.wikipedia.org/wiki/Sputnik_1
http://www.pe0sat.vgnet.nl/satellite/russian-satellites/
http://www.arrl.org/news/remembering-the-launch-of-sputnik-1-earth-s-first-artificial-satellite
http://mentallandscape.com/S_Sputnik1.htm