Moonbounce by Accident in 1943

September 27th, 2023

I have been in contact recently with Cindy Stodola Pomerleau, W2AXO, the daughter of Edwin K. Stodola, chief scientist of project Diana, about a text by Dr. Stepp, an engineer of the German Telefunken company, describing reflections from the moon with a radar system in 1943. The text has originally been published in a german nautical journal and been reprinted in CQ DL later. So it is in German only and as I think, it could be of some interest to the moonbounce community, I did a quick translation to English.
Btw.: If interested in Project Diana, the book, written by Cindy, is a must have!

Not much is known about the German technicians picking up reflections from the moon, while testing newly developed radar equipment on the island of Ruegen. Later one of them, Dr. Stepp, published a short report, he wrote:

“Back in 1943 Telefunken was to develop a system for detection and measurement of near to ground targets – ships, low-level attack aircrafts and vehicles – with a maximum outreach.

The mission to detect close to ground objects required among high transmission power and receiver sensitivity the use of least possible short waves. As the capabilities of those times allowed, a stationary facility was erected with the following characteristics:

TX pulse power:                  120 kW
Pulse duration:                    1,5 µS
Wavelength:                         53 cm, abt. 564 MHz
RX sensitivity:                      12kTo
Antenna surface:                45 m²
Polarization:                         horizontal
Number of dipoles:            8 per row horizontal
                                          80 per column vertical

The antenna could be turned around the vertical axis. It had a very narrow vertical beam with zeroes in the diagram 1.3° beside the main beam direction.

The system was named Wuerzman. In late 1943 the system was erected in the south of the island of Ruegen on a hill called Bakenberg for field testing.

The results confirmed the reckoned outreach: Ships of mid sizes could be detected up to the horizon at about 50 km, airplanes up to a height of 1000 m and up to a distance of 100 km. Under convenient weather conditions it detected targets in the harbor of Danzig (Gdansk) and the Gulf of Finland.

After the first tests I instructed Willi Thiel, a high-achieving technician, to mind the system by himself and to operate it continuously. A couple of weeks later I returned to the island of Ruegen for tests nearby Goehren. On the last day of my stay, a couple of hours before my journey back to Berlin, I visited the Bakenberg again. The sky was very cloudy and the night extremely dark. On our way to the Bakenberg W. Thiel told me about a strange fault, he mentioned the day before at the same time, but couldn´t find the reason, as after about two hours it gradually declined and at least disappeared.

After starting the operation of the Wuerzmann I made following observation: The fault appeared again, it had a length of several pulses and a bigger pulse amplitude than the strongest close targets. It appeared about two seconds after the start of transmission and disappeared pulsing analogous later after the stop of transmission. All other targets disappeared in the moment of switching off the transmitter. The fault happened only when the antenna beamed east, disappeared at once after larger changes of the bearing and appeared with a two seconds delay when beaming east again. It seemed, we targeted the moon behind the clouds. The degrading disappearance I explained as the slow movement of the reflecting body out of the narrow horizontal pointing beam together with a growing height over the horizon.

Soon after the system went into destinated operation, I never heard of further observations.“

German original in: Der Seewart, Band 35, 1974, Heft 2, S. 71
Reprint in CQ DL 1979, Heft 7, S. 328
Translation by Andreas Imse, DJ5AR

A picture of the system can be found here:
Website: http://www.deutschesatlantikwallarchiv.de/radar/germany/rd_.htm
Picture: http://www.deutschesatlantikwallarchiv.de/images/radar/germany/053748.jpg

Addendum November 6th, 2023

Cindy, W2AXO, did a great job in further investigations and published a very comprehensive history of early moonbounce on her website:
https://www.projectdiana-eme.com/the-moonbounce-zeitgeist.html

Wiolas last Farewell

June 8th, 2023

It seemed, last weeks openings, brought to us by high pressure area Wiola, had been coming to an end, but at least it was back again.

After finding a simple fault in my IC-9700 I was able to receive as usual and worked stations from Germany, the Netherlands, Denmark. I heard SM7DTT calling CQ and working some stations from UK, but he didn´t copy me. Around midnight it calmed down and PA2M on 70 cm was the last QSO.

The early morning started with Germany again and Sweden was there as well and could be worked even on 70 cm. ODX on 2 m was SM6LPF in JO78CK over 1555 km, on 70 cm SM6VTZ, JO58IJ, over 1412 km followed by SM6CEN, JO67AJ over 1409 km. But the fulminant final was brought to me by Kjeld, OZ1FF, with a QSO on 23 cm. It took a lot of patience, but at least we did it.
Thank you Kjeld!

As in the previous openings I kept an eye on 144.300 MHz, called there a couple of times in SSB, but no sign of live in analogous modes. So all QSOs were done in FT8.

NB: QSOs on 2 m in green, on 70 cm in blue and on 23 cm in red.

Addendum:
Tonight Brian, OZ7SKY, requested a FT8 sked for 70 cm in the ON4KST chat. I was pretty sure, the condx were completely gone here in the west of Ireland. But I am used to give even the crazy things a chance and as the computer is doing the job, I agreed and could decode hin at once. During the first twenty minutes we had no more, than an nice chat on KST and me telling him the level I received him. The deep QSB on his signal was between -20 and -06, when he got my report and another 15 minutes later the relief: My RRRs.

While I am writing this, my PC decodes signals of OZ2OE and OZ4VW at low levels on 70 cm. As some CQs on 2 m, after working two GMs, didn´t find any takers, I closed down the station now.

Conclusions:
Never say no to a sked request
and
NEVER BLAME A HIGH PRESSURE AREA WITH A FEMALE NAME!

Tropospheric Ducting at EI8HH

June 3rd, 2023

In Spring 2022 I installed a new antenna system for 2 m, 70 cm and 23 cm at my second home in Ireland. In the last days I could experience a long duration tropospheric opening to the continent.
On May 23rd I noticed a large ducting area to the north, shown in the Hepburn Tropo Index. Not really expecting something, I turned the antenna northwards and was surprised to hear OY6BEC in IP62mb over 958 km with 529 on 2 m. It could be monitored most of the time until June, 2nd. Even on 70 cm it could be heard from time to time, but nothing on 23 cm, even when it peaked up to S9+20 dB on 2 m on May 28th. I contacted Regin, QY1R and Trygvi, QY4TN, for skeds on 2 m, but unfortunately no signals could be detected. The two stations are quite close to sea level and the beacon is located on Mt. Sornfelli, 745 m asl.

From May 13th to May 28th I had a couple of contacts in the range, aircraft scatter allows. Beside the 2 m QSOs (green), I had some on 70cm (blue) as well. I worked the local lads on 23 cm (red) and had a QSO with Martin, GM8IEM, as I had promised him to arrange a sked, as soon as 23 cm is up and running. On May 26th a short Es opening happend and I could work Paolo, IK7UXW, with whom I had a couple of QSOs and tests from home in Mainz on 23 and 13 cm via a combination of tropo and aircraft scatter propagation in the past.

On May 29th the reach extended by tropo to the costal area from northern France to the west of Germany. ODX of the day was Günter, DG6JF/P, over 1105 km.

As the propagation conditions went to normal for me on May 30th, the next day, May 31st, startet with QSOs to Denmark on 2 m (green) and 70 cm (blue). Around noon the duct extended to the very north of Germany. ODX of the day was Oliver, DH8BQA, JO73ce over 1559 km. The duct seemed to be very narrow, as Chris, SM6VTZ, and Steffen, DD0VF, could only be worked via meteor scatter (yellow).

The duct moved southwards on June 1st with many stations from Belgium, the Netherlands and Germany. no more DX contacts were made on 70 cm, just the 2 m band was open for me. ODX of the day was Uwe, DL4DWA, over 1559 km, followed by Peter , DL3JIN over 1542 km.

And again the duct moved southwards on June 2nd and calmed down around noon. ODX of the day was Gerhard, DK1FG, over 1459 km with an outstanding signal, just, as I am used to, when QRV at home in Germany.

Fun fact: When I turned my antenna to the north in the early morning of June 2nd, OY6BEC over 980 km was still there. Turning the antenna to the east, I could hear DB0HRF, JO40ff, over 1276 km. It is located on the Feldberg, as close to my German home, that I can see the mountain out of the window of my shack.

Digital Activity on 23 cm

March 16th, 2022

Last January the QSO BANAT Association added a 23 cm section to their VHF-UHF FT8 Activity contest, open to all digital modes. Tonight it was the 3rd round in this year and my second time in participating. In February I struggled with FT8 and some QSOs could have been much faster completed by using CW, as the one with Roberto, IK2OFO, whom I worked many times before in CW on 23 and 13 cm.

**QSOs in the Digital Activity Contest on 23 cm: FT8 in red and FT4 in green**

This time I tried FT4 in some skeds and was surprised by the excellent performance of this mode. Of cource I tried with Roberto and it was as fast as in CW. Later at the end of the contest I had QSOs with Andre, DL6AST, in FT4 on 23 cm and on 13 cm as well. After that we tried MSK144 and JT9f (my favourite so far) on the higher band, but without success so far.

It seems FT4 is more robust in handling the varying doppler shift and multipath propagation caused by airplane reflections compared to FT8.

Many thanks to the friends of the QSO BANAT Association for organizing this activity on 23 cm and not dedicating it to FT8 only. This opens space for experimentation, the heart of amateur radio!

First steps on 24 GHz

February 26th, 2022

After my visit to Berlin a fortnight ago, where Thomas, DC7YS, granted me massive support in assembling my 10/24 GHz duo band rig, I have been out today to give it a try in the BBT contest.

The selected location is a building in the vine yards just a little south of my home.

It has a terrace upstairs with a perfect view to the horizons.

Despite beeing an asolute newbie, I logged two QSOs. The first one I had with Martin, DL3SFB/p on the Hornisgrinde in the Black Forrest near Freiburg. Signals were just good enough to complete in SSB over 144 km. Second was Daniel, DL3IAE, near Landau, 70 km away.

Daniels signal was extremly distorted by windmills and even in CW very hard to copy.

A test with Ewald, DK2DB, in Karlsruhe was not successful, because of a pear tree obstructing him in my direction.

The grey box houses latest Kuhne transverters for 10 and 24 GHz, driven by an IC-705. Output after all the lossy semi rigid and relays is measured to 6 W on 10 GHz and 1 W on 24 GHz. The feed a dual band horn, made by Paul, W1GHZ. The size of the dish is 80 cm. Power sources are batteries of my Makita tools.

After the Test with Ewald I decided to leave, because some strong gusts came up and the dish has a quite a good wind load. As the stuff is very heavy, the tripod is too fragile to withstand the weight plus the wind.

DB0KK: Visit at DC7YS´s Microwave Beacons

February 13th, 2022

Today Thomas,DC7YS, took me on a sight seeing tour to the Teufelsberg, a former US military facility and then straight through President electing Berlin to his beacon location in the east of Berlin.

**DB0KK, as seen from the Teufelsberg in about 16 km distance.**

**Thomas, DC7YS, with the beacon antennas to his right. It is located on a 21 storey high rise building in Berlin-Lichtenberg, JO62RM76.**

**Beacons on a turnable pole with a camera on top to check the correct direction. Thomas can turn it on demand by request. 76 ghz on top, 24 GHz beneath and 47 GHz on the back.**

24 GHz beacon
24,048.850 MHz
0.5 W
10 dB horn antenna

47 GHz Beacon
47,088.850 MHz
0.5 W
10 dB sector antenna

76 GHz Beacon
76,032.850 MHz
0.27 W
10 dB sector antenna

Looking for the James Webb Space Telescope

January 6th, 2022

**Artist conception of the James Webb Space Telescope. (Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez)**

As the long-awaited launch of JWST happened recently at Christmas and it is on the 1.5 million km journey to Lagrange Point L2, I found some time to collect information about the communication system. I was very pleased to see a frequency in the satellite band next to the 13 cm amateur radio band. It is being used for a telemetry downlink with 6 W into a pair of omni-directional antennas. Feed and LNA are not really designed for this part of the band, but still usable with some loss. Later the scientific traffic will happen in the 26 GHz Ka-band.

When looking for tracking data, I found a two line element data set at NORAD dating back to December 28, 2021 for JWSTs NORAD number 50463.

1 50463U 21130A   21362.00000000  .00000000  00000-0  00000-0 0  9999
2 50463   4.6198  89.0659 9884983 192.3200  17.4027  0.01958082    27

My tracking software accepted it and the calculated information looked very plausible, as the distance to the object was very close to the one published on the official JWST website and azimuth and elevation pointed roughly to L2. I am aware, that JWST must not fly on the direct line, as it will be in a wide orbit around.

**Five Lagrange points in the Sun-Earth-System (not to scale). (Credit: NASA)**

As in the past, when I received signals from exotic sources like ISEE-3 and Longjiang-2, I used my 3 m dish with the ring feed and LNA for 2320 MHz. I tried to use one of my PLUTO SDRs instead of the 13 cm transverter, but these are far too deaf and the LNAs gain of 16 dB is not enough to show any change in the noise, when switching it on and off. So I used a similar configuration, as before and mounted the 13 cm band ATV converter, I used to receive TV signals from the ISS, to get a sufficient signal level on the IF for the PLUTO.

**Trace of the JWST signal, it is not audible. (DJ5AR)**

Last, but not least, I saw a trace in the waterfall diagram, a little below the operating frequency. I calculated the doppler of the moving probe to about -2 kHz, which has to be combined with the doppler effect resulting of the Earth rotation. I found the signal 1 kHz too low in the reading, but the PLUTO is stabilized just by an OCXO only and the converter is not locked at all, so I didn´t worry about the difference. Turning the dish away and back to JWST resulted in disappearing and reappearing of the signal. The observed doppler drift over 1.5 hours matched quite well the calculated drift caused by Earth rotation. The shift at the rise is about -400mHz and at the set -2900 Hz, -200 Hz per hour.

Well, I am pretty sure, I have received the signal of the James Webb Space Telescope in a distance of nearly one million kilometres!

Empfang des James Webb Weltraumteleskops

6. Januar 2022

Nachdem das James Webb Weltraumteleskop (JWST) an Weihnachten gestartet worden und auf dem 1,5 Millionen Kilometer langen Weg zum Lagrange-Punkt L2 ist, habe ich beim Stöbern im Internet Informationen und Frequenzen zum Kommunikationssystem gefunden. Demnach sendet es im dem 13-cm-Amateurfunkband benachbarten Satellitenbereich (S-Band) mit 6 W an einem Paar von Rundstrahlantennen Telemetriedaten zur Erde zurück. Der Erreger in meinem Parabolspiegel und der dort installierte Vorverstärker arbeiten hier (50 MHz tiefer) zwar nicht mehr optimal, aber noch brauchbar. Die spätere wissenschaftliche Datenübertragung wird im Ka-Band bei 26 GHz erfolgen.

Das Wissen um die Sendefrequenz ist die eine Sache, die andere ist, die Antenne auf den richtigen Punkt am Himmel zu richten. Antennennachführung für Satelliten im Erdorbit besorgt bei mir ein kleines Programm, das mit sogenannten „Two Line Element Sets“, die von der amerikanischen NORAD stammen, gefüttert wird. Für das Weltraumteleskop mit der NORAD-Nummer 50463 sieht das letzte verfügbare Set vom 28.12.2021 so aus:

1 50463U 21130A   21362.00000000  .00000000  00000-0  00000-0 0  9999
2 50463   4.6198  89.0659 9884983 192.3200  17.4027  0.01958082    27

Ich war mir nicht sicher, ob das auch mit Objekten funktioniert, die den Erdorbit verlassen haben, aber der Vergleich der von meinem Programm berechneten Entfernung mit der aktuellen Angabe auf der NASA-Webseite zeigte ähnliche Werte um 920.000 km. Zudem sahen auch die Richtungswinkel plausibel aus und wiesen in etwa zum am Nachthimmel auf der Verbindungslinie Sonne-Erde liegenden Lagrange-Punkt L2. Da das Teleskop in einen weiten Orbit um diesen Punkt eintreten soll, gehe ich davon aus, dass es auch nicht genau auf der Verbindungslinie Erde – L2 fliegt.

**Die fünf Lagrange-Punkte im Sonne-Erde-System (unmaßstäblich). (Credit: NAS**A)

Für den Empfang habe ich, wie schon bei der Kometensonde ISEE-3 und dem Mondsatelliten Longjiang-2, meinen 3-m-Parabolspiegel, Ringfeed und Vorverstärker für 2320 MHz, ATV-Konverter mit LO= 916 MHz und ein ADALM-PLUTO SDR (Software Defined Radio) am Laptop benutzt, um den empfangenen Frequenzbereich in einem Wasserfalldiagramm sichtbar zu machen. DerPLUTO ist in dem Frequenzbereich leider viel zu unempfindlich, um ihn direkt nach dem Vorverstärker (16 dB Gain) einzusetzen. Deshalb dient der Konverter eigentlich nur dazu, das Eingangssignal weiter aufzupeppen und in einen empfindlicheren Bereich umzusetzen. Gleiches wäre vielleicht auch mit einem zweiten LNA mit entsprechender Durchgangsverstärkung zu erreichen.

**Spur der JWST-Aussendung im Wasserfalldiagramm. Das Signal ist nicht hörbar. (DJ5AR)**

Der langen Rede kurzer Sinn: Wenige Kilohertz unter der Sollfrequenz tauchte in der vergangenen Nacht eine Spur im Diagramm auf, die verschwand, sobald ich die Antenne wegdrehte und wieder auftauchte, wenn sie zurückgedreht wurde und die fortlaufend aktualisierte Position des Teleskops am Himmel weiterverfolgte. Die Frequenzverschiebung nach unten entsteht aufgrund des Dopplereffekts, denn das JWST entfernt sich von der Erde mit hoher Geschwindigkeit (450 m/s). Das wird dazu auch von der Erdrotation überlagert, wegen der wir uns auf der Erdoberfläche in der ersten Nachthälfte dem Objekt etwas “nähern” und in der Zweiten entsprechend “entfernen”. Das mildert die Verschiebung nach unten bis Mitternacht etwas ab und verstärkt sie danach. So liegt die Dopplerverschiebung beim Aufgang bei -400 Hz und beim Untergang bei -2900 Hz. Pro Stunde verschiebt sich die Frequenz um 200 Hz nach unten. Da die Doppler-Verschiebung aber relativ klein bleibt, stellt das kein Problem dar, vielmehr ist sie ein weiteres Indiz, das richtige Objekt im Fokus zu haben!

F1ZUY: Hrd Beacon #71 on 23 cm

November 8th, 2021

A post by F6HTJ on Facebook informed about the new french beacon F1ZUY on 1296.980 in JN19BQ.

Despite the dish is in the lower parking position at present, I turned it towards France and gave it a little elevation of 4 degrees. Very soon the first refections on airplanes could be seen 300 Hz below the given frequency. The distance to the beacon is 440 km.

The crossing of RYR70SX was strong enought to copy first fragments of the callsign. The beacon is transmitting in A1A with 5 W into a big wheel. Nearly every passenger or freight aircraft, crossing the path, causes reflections.

I am usually happy about every beacon, going on air. As there are many beacons in Europe, the selection of the frequency and its coordination is essential. As many national regualtors grant licenses for a fixed frequency only, a frequency coordination has to be done, before the beacon can go on air. F1ZUY is an example for a beacon that can be heard in a distance of several hundreds of km under normal propagation conditions. Tropospheric ducting can extend the distance to more than 1000 km, probably interfering with other beacons on the same frequency “far” away. So F1ZUY is also a bad example for the lack of coordination by the IARU R1 Beacon Coordinator. It doesn´t matter, whether the keeper didn´t know about the need of beacon coordination or just ignored it. As soon, as LA9SHF will go on air on it´s coordinated frequency of 1296.980 MHz, interference will occur in cases of tropospheric ducting over the North Sea, which happens quite often. Bad luck for beacon observers in Belgium, the Netherlands and Denmark.

So I appeal to all beacon keepers: Please contact the IARU R1 Beacon Coordinator before setting up a beacon or applying for a license!

Nice Opening tonight

November 29th, 2020

As predicted in the Hepburn forecast, there happened an opening to the west tonight. No really breathtaking distances, but at least three new squares on 2 m (two of them I already worked on 23 cm 😉 ) IN86, IN87 and IN89.

On 23 cm I tried with Grant, G1SDX in IO80FL, first in FT8, but I could only copy him via aircraft scatter due to significant doppler, inhibiting decoding of his signals. He copied me via tropo up to -11 dB, but we had a difference in power of 13 dB (36 element yagi and 10 W vs. 3 m dish and 200 W). So we tried MSK144, where I could decode him via AS, but he had no decodes of me.

It´s a very interesting path, as half of it is over water. It should be an opportunity for combined sea ducting and aircraft scatter. I hope for a chance to try.