Category Archives: Propagation

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!

1.2G_DJ5AR_IK3HHG_20130219

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.

Ik3hhg

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.

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

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

DB0AAT JN67HU
DB0AJA JN59AS
DB0FGB JO50WB
DB0GP JN48WQ
DB0LB JN48OV
DB0LTG JO31TB
DB0VC JO54IF
DB0WTT JO40LG
DB0YI JO42XC
DF0ANN JN59PL
DF5AY JN49DX
F1XBC JN06JG
F1ZBK JN38BP
F5XBK JN18JS
HB9BBD JN47GA
HB9EME JN37KB
OK0EA JO70UP
OK0EJ JN99FN
OK0EL JO70SQ
OK0EQ JN89BE
PI6ASD JO22KJ
PI7ALK JO22IP
SR6LHZ JO70SS

NAC(?) 23 cm – October 2012

October 16th, 2012

The Nordic Activity Contest is always a very good opportunity to work . . . Italians!

Tonight everything was upside down. After loosing John, G3XDY in QSB – a fact that is very, very strange – I wanted to turn the dish via south to north, when Sergio, I1KFH was meeping me. We tried and had our QSO in SSB. What else to say? Giorgio, IK3GHY followed as well as Robert, IZ4BEH and Frank, IK3HHG and Walter, IW2BNA and finally Roberto, IK2OFO.

Mille grazie. Buona notte!

NAC to Italy

NAC to Italy

Short opening on September 6th 2012

September 7th, 2012

After spending a day in Leipzig, I came home quite late. In the train already I had a look to the KST chat and on the Hepburn index. Both promised an interesting evening. After turning the dish to the west, I heard GB3USK in IO81 (783 km) very loud via tropo. In the following hours I could work G4EAT in JO01, G4ALY in IO70 (888 km), GU6EFB  in IN89 (778 km), G6HIE in IO90 and F9OE in IN78 (954 km) on 1296 MHz. The most impressive signal was the one of Keith, GU6EFB from Guernsey, who was 59 here in Mainz, by running only 10 W in SSB.

Opening on September 6th – QSOs on 23 cm – QRB > 500 km

Aircraft scatter – very special

August 27th, 2012

In the evening I had the dish pointing to the moon to perform some echo tests. After finishig that, there was some office work to do. The pc was still tracking the moon and showing the spectrum around 1296.030 in a waterfall diagram. After a while I noticed a strong signal at  .050 keyed in F2. It lasted just for a few seconds before it disappeared. I watched the display and could see it every now and then with various signal strength. Very soon I identified it as HB9BBD. This beacon is always very strong here – as long as the dish is turned in the right direction (175°), but at present it was pointing to the moon with an azimuth of 130° and an elevation of 10°. While thinking about that, I was looking at the moon outside the window, hearing the signal coming up in QSB and seeing a plane passing the moon.

Since Frankfurt airport is not too far from my QTH in Mainz, planes are passing by in a wide variety of altitudes. Using planefinder.com I was was able to find a correlation between reflections and planes flying in certain heigths, distances and directions. May be it will be possible to use aircrafts not only for forward scatter. If anyone is interested to try aircraft side scatter, please contact me. It could be helpful, when obstructions like noise sources, buildings or mountains are blocking the direct path.

Ticket to the moon

June 26th, 2012

Tonight I had a sked with Howard, G4CCH. He was there on the tick. We met in the HB9Q chat to arrange the details. What shall I say: Within a few minutes he became my first initial on 23 cm EME! As he told me later in the chat, I have been his #365 on CW (wow). After the completion of our QSO Nando, I1NDP called me to be the #2 in my just created initial list.

I am very happy now. Tnx Howard and Nando!

And finally they were heard!

June 25th, 2012

The echoes in a waterfall diagram

Tonight I added about 3 dB of power and – of course – directed the antenna to the moon to perform an echotest. I did not really expect to hear something but – what a surprise – there seemed to be a sound in the noise. I continued and after a couple of “dah-dah-dahs” it was sure, that there were my first echoes on 23 cm!

Unfortunatly the moon is setting now and so it´s too late for a QSO. I will have a whiskey and go to bed, looking forward to tomorrow.

73s & gn

Time for DX

June 19th, 2012

The NAC is always an opportunity to work stations from Scandinavia on 23 cm. Yesterday I had QSOs  with Frank, IK3HHG and Giorgio, IK3GHY in JO65 over 570 km. The signals were quite poor compared to QSOs before but were accompanied by strange pings – lighting scatter as Henning, DF9IC explained me tonight. So I wondered how the conditions would be this evening and turned my dish to the north. I started with DL0VV (JO64AD / 538 km). After a while I heard OZ9KY (JO45VX / 683 km) calling CQ and could add a new square to my collection. He was followed by SK7MW (JO65MJ / 691 km) with another new square and new country for me. In the meantime more and more stations from the UK logged in at the KST chat. Now the dish was turned to 298°. John, G3XDY (JO02OB / 547 km) could be detected on .215 and after a meep in the chat he turned his antenna to me. John produced a big signal in ssb peaking here 57 with little QSB. It was the second new country for me tonight and square #50 at all on 23 cm.

gn all

Moon II

May 26th, 2012

The DUBUS Contest was another opportunity to have a look at the moon. In the meantime I installed the preamplifier at the dish and the reading of PowerSDR showed me approx. 10 dB of sunnoise. I was surprised by seeing the tracks of not less than twenty stations in the waterfall diagram. After getting used to the special sound I could read the complete calls of OK2DL, SV1BTR, HB9SV, G4CCH, F2TU in CW.