Opening February, 10th and 11th 2015

February 12th, 2015

The first remarkable opening for quite a long time happened from 10th to 11th of February 2015. F5LENs refractive index forecast promised good conditions for these days. It started with some stations from G, appearing on 2 m. While the activity contests were going on in Scandinavia and the UK on 70 cm, a few operators dropped into the microwave chat. At least two new DXCCs could be worked before going to bed: Steward, GM4AFF in IO86TS and Gordon, GI6ATZ in IO74AJ as no. 30 and no. 31 on 23 cm. Only a few beacons could be heard via tropo: GB3FM in IO91OF, GB3MHZ in JO02PB, PI7ALK in JO22IP, OZ5SHF in JO45VX and OZ1UHF in JO57GH as a new one.

Green: Stations worked on 23 cm Red: Beacons heard on 23 cm

In the morning the inversion had moved to the north-east and never before heard beacons from Sweden became audible on 23 cm. SK6UHI in JO57TX, SK6MHI in JO57TQ, SK6UHI in JO97CJ and SK4BX in JO79LI over 1138 km as my new beacon ODX appeared on the band. Many of the Swedish stations were as loud here as locals. Some of them could be worked on 13 cm as well.

AirScout: New Version 1.1.0.0 is online!

February 10th, 2015

A brand new version of AirScout can be download. Frank, DL2ALF, has implemented a new source for airplane data as well as a couple of new features.

2015-02-10 20_12_49-AirScout - Aircraft Scatter Prediction V1.1.0.0 (c) 2013 DL2ALFMost spectacular is the ability to track airplanes with the antenna in azimuth and elevation. When enabling tracking, the user can select between several interfaces. I am using the plain WSJT-compatible “azel.dat” file. First tests on DB0NCO are very promising.

Presentation “Reflections on Air- and Spacecrafts”

January 15th, 2015Banner GHz-Tagung 2015On February 21st, 2015 Jan, PA3FXB, and I will give a lecture in Dorsten at the GHz convention. It will be held in german and partly in english and is basing on the former lectures “Let´s Bounce”.

We will talk about unusual use of Aircraft Scatter and our experiences using ISCAT. Two years ago the idea, to try ISS Bounce, was born and discussed in Dorsten. We will show what we have done in the meantime in practising this propagation mode.

A big Dish, a big Bird and a big Signal

January 6th, 2015

Jan, PA3FXB, and I skeduled a very special ISCAT test on 23 cm for today. The CAMRAS team had planned to operate PI9CAM with the 25 m radiotelescope in Dwingeloo for some astronomical experiments this afternoon. Before starting with that, we used an ISS pass with low elevation to try ISS bounce with the big dish. Such a pass ensures slow variation of azimuth end elevation angles, which is essential to track moving object like the ISS (or other spacecrafts in low orbits) with an antenna of a weight of 120 tons.

DSC_0384aWe had very strong reflections right from the beginning, but no decodes. Maybe the signal level was to high? This has to be investigated. Then we changed to aircraft scatter, although the dish had to be kept elevated at 10° by safety reasons, I got strong reflections from airplanes quite close to PI9CAM. Not as strong as from the ISS, but decodable now and it was possible to work in CW too.

Despite the fact, we had no QSO via ISS bounce, we learnt, that it is possible to track objects in low orbits with the 25 m radiotelescope, as long as the elevation keeps low. This opens up a perspective to make use of other spacecrafts as reflectors.

ISS Bounce again: now in ISCAT

January 4th, 2015

Jan, PA3FXB, and I were discussing the use of digimodes on ISS bounce for quite a while. Today we tried it with ISCAT-B and were successful with the first shot. As in the tests with Ronald, ON7FLY, on AS, we used 15 seconds periods.

 

From the moment on, traces could be seen in the waterfall diagram, decodes were possible.

2015-01-04 12_14_58-

When the ISS culmiated and the variation of the dopplershift was fastest, the frequency correction came to its limits. But while I am used to ISCAT in the meantime, I needed no decodes to hear, that Jan was transmitting RRRRs.

 

At least I decoded a 73 from him. The experiences with ISCAT in ISS bounce are very promising, although the 15 seconds periods are too long. So we have to discuss it and try with shorter ones.2015-01-04 ISCAT QSO

ISCAT – a new experience

January 3rd, 2015

Inspired by an article, published by Rex, VK7MO, and David, VK3HZ, in the latest DUBUS [1], Ronald, ON7FLY, and I performed a first test in using ISCAT-B mode (by K1JT) for aircraft scatter on 23 cm. When looking on AirScout it doesn´t seem to be very challenging to have an QSO. But Ronald is obstructed by a hill in eastern directions and he didn´t expect to have an opportunity to work eastwards on 23 cm at all.

2014-12-27 16_37_03-AirScout - ON7FLYRonald is located in JO10LT and the distance is just 388 km. He uses a 44 element yagi with only 2 W at the feedpoint. On my side a 3 m dish and 150 W are in use. First of all we tried in SSB and were able to complete a QSO after a while. I could copy ON7FLY very weak, but readable. Then we tried in ISCAT-B with 30 seconds periods and it was amazing to see, that Ronald´s signal could be decoded even when only traces appeared in the spectrum.

2015-01-02 15_28_46-His signal can be seen in the center section (The drop outs are reactions of the AGC on radar noise). The above sequence could be decoded to:

2015-01-02 15_29_22-Since the periods of 30 seconds were far too long, we needed certain airplanes to complete. then we tried FSK441 with no decodes and switched to JT6M and completed the third QSO. In the meantime I found a hint in the above mentioned article, how to reduce the T/R periods to 15 seconds. So we completed a fourth QSO in ISCAT-B again in shortest time: 2015-01-02 18_02_00-

 

[1] Rex Moncur, VK7MO, David Smith, VK3HZ, Aircraft Scatter on 10 and 24 GHz using ISCAT: DUBUS Vol. 43 4/2014

Chaos on 1296.942 MHz!

November 28th, 2014

2014-11-28 10_13_55-OK0el vs DB0AJA

There are good tropo conditions to the east from here for quite a while. I worked OK1MAC on November, 26th with an outstanding signal. OK0EA, SR6LHZ can be monitored constantly. I missed OK0EL on 1296.940, but solved the miracle today. The frequency shifted to .942 and the signal has been covered by DB0AJA. It´s nice to listen, how OK0EL in 526 km distance is battling against nearby DB0AJA,131 km away. As can be seen, DB0AJAs signal is accompanied by several dopplershifted reflections on airplanes.

 

It is interesting to see, that F5LENs refractive index as well as Hepburns tropo index don´t really illustrate the real conditions today. The conclusions is: Always perform a beacon check before switching off! The result may be surprising.

2014-11-29 09-00 F5LEN DJ5AR OK0EL

Presentation “Let´s Bounce” IIa

October 21st, 2014

Last night, when I was going to switch off all the stuff in my shack, I saw an email from Malte, DE7LMS. I opened it and found a link to a video he recorded of my recent presentation in Weinheim.