Category Archives: Aircraft Scatter

Presentation “Let´s Bounce” III

My presentation “Let´s Bounce” will be given on two more dates:

October 25th, 2014 on the 4th Hessian GHz Meeting in Fernwald

Short version of the lecture with focus on aircraft scatter and ISS bounce.
We meet at 15:00 MEST on the car park at the town hall. There will be a flee market for GHz stuff and the opportunity to test own equipment or to have QSOs with other participants.

Gaststätte “Ratsschänke”
Oppenröder Strasse 1, 35463 Fernwald-Steinbach
Locator: JO40JN33VG

November 7th, 2014, 20:00 MET on the monthly meeting of DARC OV Miltenberg, B24

Full Version with overview of propagation modes, aircraft scatter, ISS bounce and visual moonbounce.

Deutscher Amateur Radio Club e.V.
Ortsverband Miltenberg, B24
Gasthaus “Goldenes Faß”
Kirchstraße 13, 63920 Großheubach
Locator: JN49OR64JJ

If you like to attend or need further information, just send an email to dj5ar (at)

Presentation “Let´s Bounce” II

September 1st, 2014

ISS Bounce Title

After giving the presentation in english language in Clonbur, Ireland on August 25th, there will be two more dates in Germany:

September 13th, 2014 at the VHF/UHF/SHF Convention in Weinheim as a short version.

September 27th, 2014 at the “Distriktsservicetag” of DARC districts K (Rhineland-Palatine) and Q (Saarland) in Saarbrücken.

I will talk about how to surmount the horizon on VHF and up.

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.

For the short version in Weinheim the overview over the classic propagation modes will be left out.

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.

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 (at)   or to me   dj5ar (at)

NAC/IAC in March

March 26th, 2014

Last night I have been active in the Nordic and Italian Activity Contests on 13 cm. The conditions were awesome. Just four QSOs with IK2OFO (JN45), IZ4BEH (JN54, new #), DL0VV (JO64) and OZ3ZW (JO54) were written to the log, very weak Signals and rare airplane reflections most of the time. So it needed much patience and certain aircrafts to complete the QSOs as the audio record of my QSO with Roberto, IZ4BEH, shows.

It demonstrates my style of operation in aircraft scatter QSOs. I keep the transmissions short and listen in between. Only relevant information will be sent, because the duration of a reflection is typically very short. Fixed periods in aircraft scatter tests are not required at all. The first signals, received from Roberto, included the callsigns and fractions of a report. So I could be sure, that both calls were exchanged and only the report was needed. The locator was sent too, because IZ4BEH has been working in the Italian Activity Contest. It took quite a while, until a second airplane passed by near the midpoint of the path, giving us the chance to complete the QSO.

After my recent complainment about the challenge of the chat in March Contest, I got emails from Claus, OZ1FDH, and Kjeld, OZ1FF, with information about KST2ME, a tool to manage the ON4KST chat. I made use of it in the activity contests and it is a real improvement compared to the pure webclient. Thank you, Claus and Kjeld, for the feedback! KST2ME can be downloaded from Bo´s, OZ2M, homepage.

PI7ALK via Aircraft Scatter

March 17th, 2014

One of my favourite beacons to be watched via aircraft scatter is PI7ALK in JO22IP.  The beacon is running 4 W to a 4 times stacked omnidirectional antenna as described in DJ9HOs “UHF Unterlage V” on page 1001. The design of the antenna is by DC0BV. More details and the history of the beacon can be found here.

After about a minute first reflexions can be seen. The signal is increasing in strength, until the plane reaches the midpoint of the path. While other planes join, the signal will be spread by the doppler effect.

Aircraft Scatter – useful for short distances

January 3rd, 2014

Thursday night I tried a QSO on 23 cm with DG2PU in JO30PH, what´s a distance of only 80 km. Unfortunately Thomas is located down in a valley with Taunus and Hunsrueck mountains between us. His neighbor Marcel, DK7UP is closed by, but up on a hill. While it´s no problem to contact Marcel on 23 cm, Thomas signal was only 41, peaking 51 from time to time. Since beacons in similar distances often produce nice signals via aircraft scatter here, I suggested to try a QSO using airplanes to get reflections, but Frankfurt airport was already closed at that time that there was only very little air traffic. So we tried this evening. Our antennas were elevated by about than 10°, because the hot spot was in a distance of only 40 km (and a heigt of 10.000m). The second plane passed by in perfect manner and I could copy Thomas for about 10 to 15 seconds with 57, enough to complete a QSO. Due to the short distance the hot area around the center of the path is relatively small and reflections will not last too long.

2014-01-03 09_36_19-AirScout -DG2PU

Path between DG2PU and DJ5AR in AirScout

Back on Earth…..

June 17th, 2013

….. I worked in the Alpe Adria Contest last Sunday on 23 cm. In parallel there was an activity contest in Czechia. So a lot of stations from east, southeast and south filled the log.

Alpe Adria Contest 2013 on 23 cm

Remarkable was a nice SSB-QSO with Mirek, OK2UYZ in JN99FS over more than 700 km via tropo. Lane, S54AA in JN76EG could be worked, who was beaming into a large valley towards the Alps with mountains of 2.500 m. Another aircraft scatter QSO I had with Walter, IW3SPI in JN66OD, who is very, very close to the Alps.

Pathinfo by AirScout

Path information by AirScout

The reflections were rare and short but enough to complete.

Aircraft Scatter, AirScout and the ISS

February 23rd, 2013

Frank, DL2ALF has written an amazing tool for aircraft scatter prediction, called AirScout. Positions of planes are shown in a map like at or, but in addition the path and the part of it, where planes could be seen from both stations will be marked. Frank is using open street map for the maps and an elevation model of NOAA to respect the topography of the path. I made use of a beta version last Tuesday in the NAC on 23 cm and found it extremly helpful.

The latest version can be found here.

Thank you Frank!


Path DJ5AR – IK3HHG with planes and topography

As can be seen in the screenshot, the effective area is excentric to the center of the path. It is displaced southwards because IK3HHGs horizon is limited by the alps.


Eight times IK3HHG shifted by doppler, corresponding to the screenshot above

Last saturday at the GHz meeting in Dorsten Frank told me, that he integrated the groundtrack of the International Space Station to be drawn in the map too. So we have been discussing about the possibility of performing QSOs via reflections at the ISS.


AirScout with groundtrack of ISS

Back home I was very optimistic and used overflights, where the ISS  passed by nort of my location to look out for reflections of GB3MHL on 23 cm, but had no success. There was no trace at all in the waterfall diagram of my SDR. The duration of a pass is only up to 9 minutes and the expected doppler shift is +/- 84 kHz due to the high speed of 28000 km/h. So even if something could be heared or seen, tracking and decoding the signal will be another problem to be resolved.

But anyway: I am looking for somebody to perform tests with me, just to detect reflections at the ISS. Skeds are welcome via chat (ON4KST and HB9Q) or email dj5ar (at)