Category Archives: Moon Bounce

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

Moon Bounce out of the Boot

September 28th, 2019

On the annual service day of the DARC districts Saarland and Rhineland-Palatinate I had the pleasure to hold a lecture about EME basics and how to get into. Afterwards I invited the audience to try a live moon bounce QSO on 432 MHz from the parking lot outside. I had prepared some standard equipment of the kind, many might have in their shacks:

Transceiver Yaesu FT-897
15-Element Yagi (YU7EF )
PA Gemini 70, ca. 200 W
LNA SHF-Elektronik, 0,8 dB NF

EME rig in the boot, Photo by courtesy of Klaus, DF6WN

Unfortunately it was rainy outside, the moon close to the sun and a G2 solar storm in progress. When swithing on the transceiver, I noticed some quite massive local QRM. Nevertheless I contacted Bernd, DL7APV, who had agreed in a sked, by phone, to tell him about the noise and that we were ready to go.

Bernd´s array of 128 x 11 elemnt yagis during a barbeque last June

As the noise level went up and down and Bernd is one of the big guns on 70 cm, we were able to decode most of his transmissions despite all adversities. Finally we completed the QSO. That was a great job, Bernd!

I enjoyed to be in Saarbrücken and would like to say thank you to Eugen, DK8VR and his team for organising DST 2019!

Weltraumkinder schicken Astro-Alex zum Mond (German)

August 2018

Großes Finale im Weltraum-Projekt zum Ende des Kindergartenjahres!

Seit dem Auftakt mit einer Mondbeobachtung an der Paul-Baumann-Sternwarte der Astronomischen Arbeitsgemeinschaft Mainz e.V. im April konnten die Kinder viele Eindrücke vom Weltraum und dem Leben der Astronauten auf der Internationalen Raumstation sammeln. Sie absolvierten ein Raumfahrer-Training und stellten selber Astronauten-Nahrung her. Es wurde der Flug von Alexander Gerst zur ISS verfolgt und eigene Brausepulver-Raketen gestartet. Warum Funkverbindungen hinter den Horizont schwierig sind, konnte mit Walkie-Talkies selbst ausprobiert werden. Und nicht zuletzt war dann Astro-Alex selbst live per Amateurfunk von der Raumstation zu hören, als er Fragen von Schülern von Schulen in Leverkusen und Herrenberg beantwortete.

Bild: Alexander fliegt zum Mond (Ben Brinkhus)

Da der Mond ein erklärtes Ziel von Alexander Gerst ist, haben die Kinder dann Bilder gestaltet, die ihn auf dem Weg zum Mond zeigen. In Interviews erzählt er gern von seinem Opa, der als Radioamateur Funksignale am Mond reflektieren lassen konnte, was den jungen Alexander seinerzeit immens beindruckt hat. Deshalb wurde eins der Bilder ausgewählt und zusammen mit einem Foto von ihm, seinem Missions-Logo und dem Logo der Kindertagesstätte St. Laurentius ging es auf die Reise nach Italien zu Nando Pellegrini, der als Funkamateur unter dem Rufzeichen I1NDP eine große Sendestation betreibt. Mit seinem Parabolspiegel, der einen Durchmesser von 10 m hat, sendete er die Bilder im 23 cm Amateurfunk-Band im sogenannten Slow-Scan-Television-Verfahren, ähnlich einem FAX, in Richtung Mond. An der Oberfläche unseres Trabanten wurde die Funksignale reflektiert und trafen zweieinhalb Sekunden später mit Lichtgeschwindigkeit wieder auf der Erde ein.

Bild: Radioteleskop in Dwingeloo

Hier hatte sich das historische Radioteleskop in Dwingeloo in den Niederlanden bereitgehalten, um die Bilder nach ihrer Reise über fast 800.000 km wieder aufzufangen.Betrieben wird die denkmalgeschützte Einrichtung in der Provinz Drenthe im Nordosten der Niederlande von der CAMRAS Stiftung, in der eine große Zahl von Funkamateuren mitarbeitet. Hier, an der erst vor fünf Jahren aufwändig restaurierten Parabolantenne von 25 m Durchmesser, haben die italienische Künstlerin Daniela de Paulis und der niederländische Funkamateur Jan van Muijlwijk, Rufzeichen PA3FXB, im Jahr 2009 das „Visual Moonbounce“ genannte Verfahren entwickelt, bei dem sie im Rahmen von Kunst-Projekten und Astronomie-Events der „Astronomers without Borders“ mit Hilfe geeigneter Gegenstationen in Italien, Brasilien, Großbritannien und der Schweiz Bilder am Mond reflektiert lassen.

Dank guter persönlicher Kontakte konnten die beteiligten Funkamateure dafür gewonnen werden, die Bilder der Ebersheimer Weltraumkinder im Rahmen einer öffentlichen Veranstaltung in Dwingeloo zum Mond zu schicken, um den dortigen Besuchern „Visual Moonbounce” eindrucksvoll zu demonstrieren.

Bild: Alexander Gerst (ESA)

So kam es, dass nicht die ESA, sondern die Weltraumkinder der Kindertagesstätte St. Laurentius in Mainz-Ebersheim Alexander Gerst zum Mond geschickt haben.Wir danken Daniela de Paulis, Jan van Muijlwijk, Nando Pellegrini sowie dem Team CAMRAS für die Unterstützung unseres Weltraum-Projekts! Das Bild vom Flug zum Mond hat das Weltraumkind Ben Brinkhus gestaltet.

Ansprechpartner für das Weltraum-Projekt: Regina Imse,
Kath. Kindertagesstätte St. Laurentius, Großgewann 2,
55129 Mainz-Ebersheim

Bildnachweis:
Zeichnung „Alexander fliegt zum Mond“: Ben Brinkhus
Alexander Gerst, Horizons-Logo: ESA
Radioteleskop Dwingeloo: Andreas Imse
Logo der Kindertagestätte St. Laurentius, Mainz-Ebersheim
Reflektierte Bilder: Nando Pellegrini und Team CAMRAS

Worked All Continents on 23 cm

October 20th, 2017

To be honest, I am not really an awards collector, but this one, as a kind of poor mans DXCC, is a must, in particular, when active on higher bands.

Moon Bounce on 13 cm

April 28th, 2017

Sometimes you hear words that hurt. Especially if they are true: Some years ago I tried 13 cm EME with Dan, HB9Q, and couldn´t copy anything of him. His comment after the test: “There is no way, not to hear me!” This is frustrating.

So I forgot Moon Bounce on this band and had fun with other activities, mainly on 23 cm. But the over 30 year old equipment caused more and more problems. So I started collecting parts and modules for a new transverter system covering 23 and 13 cm. It had been finished for the last VHF/UHF/SHF contest in March and was tested with good results. In the end of March I tried EME again after 2 years of absence. On 23 cm it worked fairly, but on 13 cm the drift was a serious problem. In a test with Alex, ZS6EME, I could decode his strong Signal, but not vice versa. So I added 10 MHz Double Oven Controlled Oscillators as references to stabilize the transverters.

PY2BS in WSJT-X Wide Graph

Today I tried with Bruce, PY2BS, and heard him strong in the speaker during his prior test with Toshio, JA6AHB: 1131 -6 2.5 2305 #* JA6AHB PY2BS GG66
At this time his elevation was -1.7° and the moon still under the horizon. After the moon set in Japan, we started:

1155  -8  2.9 1184 #* DJ5AR PY2BS GG66
1157 -13  3.6 1157 #* DJ5AR PY2BS GG66
1159 -10  2.7 1137 #* DJ5AR PY2BS GG66
1200  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1201 -10  3.1 1114 #* DJ5AR PY2BS GG66
1202  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1203  -9  3.3 1089 #* DJ5AR PY2BS GG66
1204  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1205 -10  2.9 1066 #* DJ5AR PY2BS GG66
1206  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1207  -9  3.1 1043 #* DJ5AR PY2BS GG66
1208  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1209  -9  2.7 1019 #* DJ5AR PY2BS GG66
1210  Tx      1400 #  PY2BS DJ5AR JN49 OOO
1211 -10  3.0  994 #* DJ5AR PY2BS GG66
1212  Tx      1400 #  PY2BS DJ5AR JN49 OOO
1213 -11  2.2  969 #* DJ5AR PY2BS GG66
1214  Tx      1400 #  PY2BS DJ5AR JN49 OOO
1215 -22 -2.5  946 #  RO
1216  Tx      1400 #  RRR
1217 -10  3.1  919 #* RR -20 DB
1218  Tx      1400 #  73 BEST -8

As he switched his RX from 2304.070 MHz to my TX frequency 2320.070 MHz at about 12:14, we completed very fast. I am very pleased now with my first initial on 13 cm, a new grid square, a new ODX, a new DXCC and a new continent! After setting up a new Initials List for 2320 MHz and writing this blog entry, I enjoy my “Radio Operators High”!

DJ5AR on Radio HR1 (german)

September 28th, 2014

Short talk about reception of space probe ISEE-3, moon bounce and radio astronomy with radio editor Udo Langenohl, DK5YA, on german radio station HR1 in a Sunday morning program “Lust am Hören” (fancy listening).

Presentation “Let´s Bounce”

June 22nd, 2014

On July 24th, 2014 on 19:00 CEST I will talk about how to surmount the horizon on VHF and up at the local DARC Club in Bodenheim near Mainz.

After giving an overview over the classic propagation modes Es, Aurora, MS and Tropo, I will explain, how aircraft scatter and ISS bounce work. EME will be subjected too and the presentation will be completed by an introduction to “Visual Moonbounce” as performed by Daniela de Paulis.

Location:
Deutscher Amateur-Radio-Club e.V.
Ortsverband Bodenheim
Haus der Vereine
Laubenheimer Str. 22
55294 Bodenheim

The admission is free, but please register via email to
DK2FQ wolfgang.beer (at) gmx.net or to me dj5ar (at) darc.de

Visual Moonbounce

April 13th, 2014

The italian-dutch artist Daniela de Paulis is the inventor of visual moonbouce. Slow scan television is used to send pictures towards the moon. When the bounced signals will be received and visualized, the pictues are a kind of distorted and win a very special charm.

The pictures shown below are screenshots, I took during a performance on April 13th, 2014.

I am very proud, that Daniela has choosen one of my pictures for her performance. It shows the moon resting on clouds and has been bounced at the moon.

Nando, I1NDP, transmitted a selection of pictures in SSTV, to be received by PI9CAM with the radiotelescope at Dwingeloo. Using a “GOOGLE Hangout”, an audience from all over the world watched live, how Daniela and her team (Nando, I1NDP, Jan, PA3FXB, and many more) were bouncing all the pictures at the moon.

A video recording of the session can be found here.

Reopening of Dwingeloo 25 m Radiotelescope

April 5th, 2014 After an extensive restoration by ASTRON and the CAMRAS foundation, the 25m dish of the radiotelescope in Dwingeloo has been reopened by astrononomer, radio amateur and Nobel laureate Prof. Dr. Joseph Taylor, K1JT, on April 5th, 2014.

In future it will be used by radio amateurs, amateur astronomers and artists for certain projects.

Digital World – Digital Moon

March 11th, 2013

Despite all the discussions about using digital modes in moonbounce I want to gather own experiences. After installing WSJT last Xmas I could decode a couple of stations on EME without any problems. First TX tests resulted in an intolerable frequency drift, which could be limited with the installation of a crystal heater. Then I started with real tests, but in all skeds no one could decode me! I had no clue what went wrong. So I changed – quick and dirty – the PC producing the audio stream. Now OK1CS, HB9Q and G4CCH could be worked in JT65C. Last sunday morning I saw a big signal in the waterfall diagram of my SDR. It was JA6AHB and it was a question of a few minutes to put him to the log. All stations worked so far, have been audible in my headphones.

I think, in general it is nice to use digital modes to work others via EME. But there is much more skill in involving the ears to have success in completing an QSO. It´s always great to HEAR the final rogers. Despite that I will not deny the use of digital modes. Why not working someone digital and then, maybe after some improvements, top it in working him in CW again? As long as all information like callsigns, reports and rogers, necessary for a complete QSO, have passed the radio channel, it will be a valid QSO. This is my position.

I will continue to explore digital modes:

The TX signal will be processed on my FT-987 with a seperate PC. RX is done with my SDR and another PC. By not typing in the other callsign or using call3.txt on the RX side I am quite sure in ‘really’ receiving the callsigns.