Tag Archives: SHF

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.

VHF-UHF-SHF Contest March 2014

March 3rd, 2014

Many thanks to all enthusiasts on 23 and 13 cm, who spent up to 20 minutes to complete a QSO with me. Tropo conditions were not too good this time and especially 2320 MHz it seemed to have an additional attenuation on all signals. But never the less, quite a lot of QSOs filled the log. More stations than I could handle, requested skeds via the ON4KST chat. I have to apologize for all my replies like “pse qrx, meep u when free”, I forgot about. So, all I can say is:

Please excuse me for forgetting to meep you!

Indeed, this chat is a great tool, I don´t want to miss it. But in times of contest it can be a challenge, like the contest itself. I will not apply for to do without, it is rather a question, how to use it. The amount of information, flowing over the screen, is immense. On saturday afternoon or on sunday morning, relevant entries might disappear within less than a minute. So I have to think about optimizing my software tools.

QSOs on 1296 MHz

Skilled VHF Operators may smile, when I tell them, 58 QSOs on 23 cm and 19 QSOs on 13 cm are hard work. The sum of that is the number they work within the first hour of their contest section. But in fact, the world above 1 GHz is a different one. The beams of the antennas are much narrower compared to VHF and UHF. The dense of stations is much less, since it is not like plug and play to become QRV up there. The attenuation increases GHz by GHz and all that results in real work for most of the QSOs. There are only a few big guns on 23 cm to be heard from any antenna direction. So the band seems to be empty, even at contest time. But the chat is an oppotunity for all kind of stations to arrange skeds and to have QSOs over distances of several hundred kilometers. And, especially when using aircraft scatter, patience could be needed to complete.

QSOs on 2320 MHz

Review: Activityweek Rhineland-Palatine 2014

January 8th, 2014

The battle is over. I had my last QSO with Patrick, DH2PA on 70 cm just before the contest closed after seven days. There was a big regional activity on VHF, UHF and SHF, much more than last year. Finally I logged 414 QSOs on the four bands I have been active, compared to 266 in 2013. It is remarkable that there were many locals with improvised equipment on 23 cm. Just one new square on 2320 MHz could be worked during the activityweek: IK3GHY in JN65DM via aircraft scatter. But collecting new squares is getting harder and harder, the more are already worked. The tropo conditions remained normal during the seven days, so there was less DX than last year. This time I found four partners for 4-band-QSOs: DL7QY, DL8YG, DF5AY and DB6NT.

The top five of the most worked stations in this contest:
1. DL7QY    24 QSOs on 4 bands (2 m, 70 cm, 23 cm, 13 cm)
2. DC8WPA   18 QSOs on 3 bands (2 m, 70 cm, 23 cm)
   DJ1FZ    18 QSOs on 3 bands (2 m, 70 cm, 23 cm)
   DK0RLP   18 QSOs on 3 bands (2 m, 70 cm, 23 cm)
   DK7UP    18 QSOs on 3 bands (2 m, 70 cm, 23 cm)

Thank you all for your support and your patience!
        total       District K      DL ex K    F,I,OK,OZ,SM   Squares
BAND    QSO Stn     QSO Stn DOK     QSO Stn     QSO Stn       total new
 144    183  94      99  43  26      82  48       3   3          15
 432    134  66      69  31  20      65  35       0   0          10
1296     79  37      36  14  12      34  16       9   7          16
2320     19  11       1   1   1      15   7       3   3          10   1

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 http://planefinder.net or http://www.flightradar24.com, 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) darc.de

Review: Activity week Rhineland-Palatine 2013

January 14th, 2013

It was big fun working in contest for a whole week. I felt a bit like Phil Connors in the movie “Groundhog Day” (german: “Und täglich grüßt das Murmeltier”), in meeting most of the stations again day by day. My main activity was in the evenings on 23 and 13 cm, using 2 m, 70 cm and the ON4KST chat to arrange skeds. The conditions were slightly over normal but increasing on monday with a small opening to France. During the seven days I could work one new square on 2 m (JN15), two on 23 cm (JN09, JN15) and three on 13 cm (JN09, JO42, JO44). There were only two 4-band QSOs with DL7QY and DC1UR.

My top 5 of the most worked stations in this contest are:
DF8PR    16 QSOs on 3 bands (2 m, 70 cm, 23 cm)
DC8WPA   15 QSOs on 3 bands (2 m, 70 cm, 23 cm)
DK7UP    13 QSOs on 3 bands (2 m, 70 cm, 23 cm)
DL7QY    12 QSOs on 4 bands (2 m, 70 cm, 23 cm, 13 cm)
G3XDY     8 QSOs on 2 bands (23 cm, 13 cm)

Thank you all for your support and your patience!

        total      District K     DL ex K    France     I,OE,G,LX    Squares
Band    QSO Stn    QSO Stn DOK    QSO Stn    QSO Stn    QSO Stn      total new
 144    100  58     72  31  18     25  24      3   3      0   0        11   1
 432     65  31     54  22  15     11   9      0   0      0   0         6   0
1296     73  34     27   9   8     21  11     14  10     11   4        21   2
2320     28  15      2   2   2     14   8      5   3      7   2        12   3

Opening October 19th – 23rd

October 24th, 2012

The beacon check in the morning of October 19th gave me the impression of a strong inversion over southeast Germany. When looking for Stations on 23 cm on the SDR I noticed a big signal in CW: OE5VRL/5 calling to Hungary. I gave him a meep in the chat to tell him how strong his signal was here in Mainz, despite the fact that I was in the back of his 3 m dish. After turning the antenna to me he was stronger than many locals.

In the following days a lot of DX stations from OK, SP, HA, S5, OE, HB9, F, LX, G, PA, I and OZ filled the log while the inversion moved from east to west. All of the four OK beacons could be heard on 23 cm. Sometimes it was a little bit confusing when I was looking for new DX beacons and DB0AAT, DB0AJA, DB0GP, DB0LB, DB0FGB, DF0ANN, HB9EME and others could be heard in nearly any direction the dish was pointing to.

QSOs on 23 cm > 400 km

QSOs on 13 cm > 400 km

QSOs on 13 cm > 400 kmI am happy with a couple of new squares on 23 and 13 cm. Two new countries on 13 cm made it perfect: S51ZO in Slovenia and I1KFH in Italy. But I fear that it was more aircraft scatter than tropo.

Beacons heard on 23 cm


IARU-Region-1 UHF/Microwaves October Contest

October 8th, 2012

“Bad weather and bad conditions” that is, what most comments say about this contest. The weather here in Mainz was bad too, but I cannot compare the conditions with the contests in the last years, because my last participation in this contest was in 1990. This year it ended up in 50 QSOs on 23 cm and 19 on 13 cm. I am quite satisfied with these results.

QSOs on 23 cm


QSOs on 13 cm

My new ODX on 13 cm is OL9W in JN99CL over 720 km. A lot of new squares could be worked too. Many DX stations were nearly as strong as they were on 23 cm.