Tag Archives: dish

Dismantling the Rotor

August 2nd, 2016

After having serious issues with the elevation drive, I dismantled the BIG RAS Rotor last weekend. A construction to support the dish by keeping it in an upright position has been installed.

DSC_1124aAfter opening the case of the rotor, the failure could easily been seen: The cogwheel does not fit into the worm gear. Instead it slips over it. I hope to find a solution soon.

DSC_1134a

Update 2016-08-03: SPID offered to check and repair it as a warranty case! So it is on the way to Poland now. TNX to Jacek of SPID Elektronik!

Presentation “Let´s Bounce” IIa

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.

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) darc.de

New 23 cm Beacon DB0XY in JO51EU

Jürgen, DK2AN phoned me tonight, to tell me, the new beacon DB0XY will be transmitting on 1296.910 MHz. It is located on the Bocksberg in the Harz mountains in JO51EU, about 750 m asl. The power is 10 W into a 4 times double quad, omnidirectional. The keying is in A1: callsign, locator, carrier, dashes, carrier….

In a first quick try it could be received here with 519 to 539 via tropo. When Planes crossed the path, the signal increased up to 559.

Another beacon will be installed on 13 cm soon. The intention is to provide beacons for monitoring via aircraft scatter.

Please spot any reception in the DX cluster.

Reception of HAM TV aboard the ISS

At present the HAM TV transmitter aboard the International Space Station performs blank transmissons until August 6th, 2014. No camera is attatched, so only signal levels can me measured.

This was an opportunity for me to check out the FSTV-equipment, I set up during the last months. So my very first attempt last night was successful. I used the pass at 23:50 UTC on July 30th, 2014.

2014-07-31 01_58_52-U__Amateurfunk_ISS_HAM TVI am looking forward to see some pictures in near future.

Reception of ISEE-3

July 30th, 2014

For quite a while now I try to catch a signal of ISEE-3. Because of severe thunderstorms, there was no opportunity to check out yesterday. But today (July 30th, 2014) is the day to listen to this 36 year old bird.

The signal of the beacon on 2,270.414 MHz isn´t too strong, but clearly audible in the speaker. The actual distance is about 1.6 million km, the furthermost man made signal I ever received!

2014-07-30 11_30_21-HDSDRThe downlink transponder A on 2.270.4 MHz uses an antenna array with a gain of 7 dBi, a beamwidth of 12° and circular polarisation. The nominal TX power is 5 W.

The equipment I am using, is just a FUNcube Dongle Pro with a 13 cm ATV converter (LO 916 MHz, IF 1,354 MHz) and a 13 cm LNA near the 23/13 cm dual band ringfeed at my 3 m dish.

Frequency calibration is performed on ordinary 13 cm beacons like DB0UX. The dish calibration is done by optimizing sun noise on 23 cm or the levels of SIRIUS satellites on 13 cm.

The rhythmical fading of the signal seems to be caused by the space probe´s spin of 19.76 revolutions per minute.

Impressive Thunderstorm

June 10th, 2014

2014-06-09 db0aja RS
The destructive thunderstorm in the Köln/Düsseldorf area last night was intense enough to provide rainscatter even on 1.3 GHz. DB0AJA near Würzburg in JN59AS could be heard with the typical rainscatter sound when the dish was heading 325°. An awful lot of water must have been in the air. The total distance of the signal path was about 400 km (150 + 250).
2014-06-09 21_18_29-PowerSDR-DB0AJA RS


The waterfall shows the spread of the signal. DB0AJA runs 20 W output into a 16 element Flexa yagi beaming northwest.

Reopening of Dwingeloo 25 m Radiotelescope

 

DSC_0383a After an extensive restoration by ASTRON and the CAMRAS foundation, the 25m dish of the radiotelescope in Dwingeloo has been reopened by astrononomer, radio amateur and Nobel laureate Prof. Dr. Joseph Taylor, K1JT, on April 5th, 2014.

DSC_0258In future it will be used by radio amateurs, amateur astronomers and artists for certain projects.

Another strange constellation (Update)

While performing my beacon check on December 16th, 2013 at 8:30 UTC, I stated that all beacons seemed to be at a normal level. Except, when looking for DB0FGB (JO50WB) with the dish heading 85°. There was a constant carrier of about 20 dB 15 kHz up, keying F1ZBK (JN38BP). Expecting a big signal, I turned the dish to France. But the beacon was only 15 dB with QSB, when beaming directly to it at 228°. Then I turned the dish back to 85° and noticed, that HB9EME (JN37KB) joined the party.

2013-12-16 09_30 F1ZBK HB9EME 85deg

DB0FGB, F1ZBK and HB9EME with dish heading 85°

The rain radar didn´t show anything unusual and the F5LEN Refractive index forecast for Europe promised only marginal tropo conditions for this area. Only DL7QYs Condition Index for south Germany has been on a level of 7 (1 = poor; 10 = extreme).

2013-12-16 09_00 F5LEN index

F5LEN Refractive Index

DB0FGB was a bit above normal at about 15 db with little QSB up and down. F1ZBK was constantly at 20 dB, when beaming 85° and around 15 dB with QSB heading 228° (direct). HB9EME was up to 20 dB in 85° and peaking 15 dB in fast QSB when beaming 198° (direct).

Green: Paths from Mainz to the beacons
Orange: Paths of the beacons to the area of the supposed reflection point

I checked HB9BBD, F5ZBS, F1ZBI and others, but couldn´t see any similar effects. The angle was very small. When turning the 3 m dish 5° left or right, the signals disappeared. These conditions lasted for about one hour.

Path DJ5AR to DB0FGB (by AirScout)

Topographic profile between DJ5AR and DB0FGB

The horizon in 85° is about 80 to 90 km off. A plausible explanation could be a strong troposheric duct between the beacons and a reflecting topographic formation.

Update:

In issue 2/14 the german magazine “Funkamateur” published an article by Matthias Hornsteiner, DG4MHM “Prognosekarten für troposphärische Überreichweiten” (Prediction maps for troposheric ducting). Matthias explains the basics of ducting and analyses the models, the well known refractive index maps of F5LEN and W. Hepburn are basing on.

So I had the intention, to ask him about a possibility for a reconstruction of the wheater constellation of that day. I have to thank him very much for his comprehensive answer.

As Matthias explained, the situation, shown on the map, was quite common for this, as he describes it, “anti-winter”. But it holds the possibility, that warm air might glide onto cold air at ground level. And indeed, when he reviewed the data of weather balloons launched at Stuttgart on that day, he found indications for a strong inversion in an estimated level of 400 to 600 m over south Germany. That matches!

In a distance of 200 km from here, the the topographic profile shows a formation, high enough to reach the level of this duct, as well as the mountains of the Fichtelgebirge do, where DB0FGB is located. The distances from Mainz to the area of the supposed reflection point is between 200 and 250 km. From F1ZBK and HB9EME it varies between 400 and 500 km. So the total path should have been between 600 and 750 km.