New Antenna System at EI8HH

June 4th, 2022

When going to Ireland in May, I went with a trailer and could take a pneumatic mast and some antenna stuff with me. So I setup a 2 x 7 elemt yagi for 2 m, a 15 element yagi for 70 cm and a 67 element yagi for 23 cm. The rotator is a Spid BIG-RAS/HR, so elevation is possible as well. There are SHF-Electronic LNAs at each antenna and Gemini linears with 200 to 300 W driven by an IC-9700.

On 2 m I could log a couple of QSOs in FT8 (blue) and SSB (green) so far and have been lucky to use some tropo to France on May 27th and 28th (F6DBI, IN88ij, 716 km and F8BON, IN86wv, 903 km) and Spain on May 28th (EC2BBS, IN93bi, 1262 km).

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.
Teufelsberg, as seen from DB0KK
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


Aircraft Scatter Podcast

February 7th, 2022

Today I had a talk about Aircraft Scatter with Michael, OE1CMW, who recorded it to produce a podcast for his series “ON AIR – Amateurfunk D-A-CH“. As it´s in german language, I keep this post in german.

Heute habe ich mit Michael, OE1CMW, über Aircraft Scatter gesprochen. Michael hat das Gespräch für seine Podcast-Reihe “ON AIR – Amateurfunk D-A-CH” aufgezeichnet.

In meinem Blog finden sich viele Beispiele zu QSOs und Bakenbeobachtungen als Anregung für eigene Aktivitäten. Unter dem Menü-Punkt “Aircraft Scatter” habe ich die QSO-Prozedur ausführlich beschrieben. Das Programm AirScout von Frank, DL2ALF, gibt es als Download für das Betriebssystem Windows.

Hier als Beispiel ein QSO mit DJ5BV auf 23 cm. Man hört sehr schön die Änderung der Tonhöhe infolge des Doppler-Effekts und verschiedene Signaltöne durch Reflexionen an verschiedenen Flugzeugen.

Wenn man Baken beobachten will, sollte man WideGraph von WSJT-X mitlaufen lassen, dann kann man auch schwächste Signalspuren sichtbar machen und auch die Doppler-Verschiebung sehr gut visualisieren.

F5ZBM in Sendeart F1

DB0UX screwing in Waterfall

January 14th, 2022

F5ZNI on 13 cm in JN19BQ, 440 km away, is a good indicator for troposheric duting to the west. Drifting up and down, it is transmitting just a little below GPS locked DB0UX in JN48FX, just 105 km to the south.

This is, how it usually looks, when I monitor F5ZNI on about 2320.899 MHz. DB0UX to the right with space 800 Hz lower. F5ZNI about 1250 Hz lower with space 500 Hz up.

Tonight DB0UX appeared a little different, somehow screwing through the waterfall display.

What happened?

Well, there is a windmill in 500 m from my QTH a little north of the path to F5ZNI and the wind raised to blow with 6 km/h from NE ……

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

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

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: NASA)

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!

New Activity Contest for digital modes on 23 cm

December 21st, 2021

The QSO BANAT Association organizes FT8 Activity Contests every 1st and 2nd Wednesday each month on 2 m and 70 cm. From 2022 on they added a 23 cm Activity Contest on the 3rd Wednesday. In respect, that FT8 is not useful with propagation modes like aircraft scatter on this band due to the doppler effect, it is open for the use of ISCAT, JT65, JT6m, JT8f, JTMS and MSK144 as well.