Tag Archives: DJ5AR

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

ISS Bounce even in SSB

February 17th, 2014

After getting familiar in working us in CW via ISS Bounce, Jan, PA3FXB and I were looking for a new challenge. So we decided to try it in SSB. After some tests in the last days and finding a workaround for a bug in my PowerSDR, we completed a two way contact in SSB on a center frequency of 1296.300 MHz tonight. The doppler compensation worked well on both sides. Just minor corrections with the RIT were neccessary. The signals weren´t as strong as they were in the days before, but strong enough to copy even some 73s at the end. It seems to be the first SSB QSO via reflections on a spacecraft at all.

The audio recording starts with my recording of PA3FXB on one channel synchronized with Jans recording of my signal on the other channel.

Just another ISS Bounce QSO

February 13th, 2014

Tonight I had a sked with Jan to try ISS Bounce once again. We agreed in trying SSB after getting in contact in CW. Jan appeared shortly after rise of the ISS and it was no problem to exchange reports and confirmation with strong signals. Then we switched to SSB and I could hear Jan clearly, but my tracking software refused to stay in SSB mode. So I have to fix this bug for our next test.

Later we tried to detect reflections from Iridium 4. We expected to see something about -19 dB, but nothing was to be seen in the waterfall diagram. Maybe that the choosen pass wasn´t too high in elevation and we will try again. When Jan was operating PI9CAM on February 2nd, faint traces of reflections on COSMOS 1823 could be detected by Hannes, OE5JFL, Dan, HB9Q and myself. As it is quite time-consuming, to find reasonable passes of satellites, I wrote a small Excel tool get an overview over satellites, passes and elevations. It can be found for free download here: Visibility

Macros have to be enabled in your Excel. Just enter the date, time, period and the locators of the two stations in the approriate cells, click “Calculate” in the “ADDINS/Satellite Overview” menu and the worksheet will be updated. Don´t forget to fill the TLE worksheet with the latest data of your choice.

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!
Statistics:
        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

Opening September 21st 2013

September 21st, 2013

While performing a last beacon check before going to bed and all local beacons were quite normal, I took notice of a weak carrier 1 kHz up of F1ZBK on 1296.855 MHz. After optimizing the antenna and using a narrow filter I heard EA2TZ in IN93BF over 1073 km for the first time ever.

2013-09-21 20-50 EA2TZ

Left signal: F1ZBK/B, right signal: EA2TZ/B

 EA2TZ/B as received by DJ5AR over 1073 km on 23 cm

After posting this information in the ON4KST chat, Matej, OK1TEH sent the phone number of EA2TO and told me that Javier is currently QRV on 23 cm from IN83. After exchange of a few SMS he came back on my CQs and we could complete a QSO: A new DXCC, a new square and a new tropo ODX of 1173 km on 23 cm!
When closing down the station I had a quick look on 70 cm. There he was again: EA2TO in SSB. We had a nice chat and for me: A new DXCC, a new square and a new ODX of 1173 km on 70 cm!

Only 2 QSOs tonight, but I am very happy with it.

Rainscatter on 23 and 13 cm

June 20th, 2013

While performing my daily beacon check, a strange constellation around 1296.850 MHz appeared on the display of my SDR. The dish was turned to 254° at that time, to look for F5XBK.

2013-06-19 RS F5XBK F1ZBK ON0NR HB9EME

From left to right: F5XBK, F1ZBK, ON0NR, HB9EME

Combined with strong QRN and radar noise I could copy F5XBK in JN18JS quite normal via tropo but also F1ZBK in JN38BP, ON0NR in JO20KJ and HB9EME in JN37KB via a rain scatter point in JN39LP. Later DB0GP in JN48WQ and DB0AJA in JN59AS could be heard too.

Then I continued to have a look on 2320 MHz where DB0UX in JN48FX, DB0FGB in JO50WB and DB0MJ in JO31UB could be copied via a scatter point in JN39JR.

Beacons heard via rain scatter on 23 and 13 cm

The map shows the location of DJ5AR in Mainz (green marker) in relation to the scatterpoints (blue markers). The paths to the beacons on 1296 MHz are in light blue and on 2320 MHz in dark blue. For that time heavy thunderstorms with flooded roads and cellars were reported for the area of Hermeskeil in JN39.

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.

ISS bounce V: The QSO!

May 23rd, 2013

STS-133 International Space Station after undocking 5

(Copyright by NASA [Public domain], via Wikimedia Commons)

After a lot of tests and improvements have been done in tracking the doppler shifted signals, Jan, PA3FXB any I had another try around 1296.300 MHz this morning. Both of us performed compensation of the own doppler component as well in receiving as in transmitting. We agreed in using  the EME QSO protocol and periods of 30 seconds.

PA3FXB as received by DJ5AR

Jan appeared within my filter bandwidth as soon as the ISS became visible to both of us. His signal strength was peaking up to nearly 20 dB above noise and was easy to copy. The tracked frequency seemed to be stable until the ISS culminated. Then the variation of the doppler shift became so rapid that the compensation mechanism was not fast enough anymore. But that happened to the very last part of our QSO while we were transmitting our final 73s. So I can state that the best signal quality can be expected during the ascending and the descending parts of the pass.

In the meantime I received Jan´s recording. Listen how DJ5AR sounds on his side:

DJ5AR as received by PA3FXB

Many thanks to Jan for his cooperation and his patience in numerous tests before.

This success is dedicated to our fathers, who suffer from the same disease!

If you are interested in a try, do not hesitate to contact Jan or me. You can find us in the HB9Q 1296 MHz EME logger or in the ON4KST microwave chat, when QRV.

 

ISS bounce IV

May 10th, 2013

Today Jan, PA3FXB and I used ISS passes to improve doppler compensation.

1.2G_DJ5AR_PA3FXB_20130510_083025

The first pass of three was disappointing because no reflections could be detected. In the second one I found Jan shortly after his window opened. But it sounded more like a strange kind of music than CW, Jan stated after listening to the audio file, I recorded of his signal. The reason were too long steps in timing for the frequency correction. I reduced it for the last try from 100 ms to 10 ms. After some recalibration of frequency and rotor control I started the system again when the ISS rose.

2013-05-10 13-43

I could hear Jan without any manual corrections immediately after he started transmissions. The frequency tracking worked quite smoothly and reading his CW was possible without any problems.

PA3FXB as received by DJ5AR with QRG tracking every 10 ms

The audio file contains Jan´s signal in three periods. From 0:00 to 1:00 the signal raises while being on the upper flat part of the doppler curve shown above. During the second period from 1:00 to 2:00 the signal passes the steep part and even an adjustment every 10 ms leads to a kind of jumping signal. When receiving the third period, the signal was quite stable again and faded out, while the ISS moved to the eastern horizon.

In between his TX periods Jan tried to catch my signal without doppler compensation, just playing with the RIT. He successfully got a short part of my transmission:

DJ5AR as received by PA3FXB without QRG tracking

Doppler compensation on my TX part did not work. It seems that the SDR does not accept CAT commands for frequency change while transmitting. So we will work on another strategy, where TX frequencies remain fixed and both stations will do full doppler compensation only while receiving.