Amateur radio, space, technology and other geeky stuff by Alexandru Csete
Peter Scott (OZ2ABA) and myself gave a presentation at the 2018 AMSAT UK colloquium about the avionics in the Copenhagen Suborbitals Nexø II rocket. This included the radios and the DVB-S2 video transmitter used on the rocket. A video recording of the presentation is now available on the AMSAT UK YouTube channel, thanks to BATC.
Continue reading “Avionics in the Copenhagen Suborbitals Nexø II rocket”
With both the frequency controller and FFT plot widgets in place gqrx was ready for the first on the air tests. The video below shows the first reception of the AO-27 amateur radio satellite during orbit 92436 and 92437, using the Funcube Dongle receiver that I use for portable space communication.
Sunday, April 10, 2011 we met at OZ7SAT to start working on our antennas. The weather is becoming better and we have a few plans for upgrading the antenna farm at AMSAT OZ headquarters.
This page collects various amateur radio satellite and cubesat receptions carried out using the Funcube Dongle. The Funcube Dongle is a small USB-flashdisk sized software defined radio receiver for 67 MHz – 1.7 GHz intended to be the ground receiver for the FUNcube satellite by AMSAT UK. It is well suited as a ground receiver for low cost space communications.
The purpose with this page is to demonstrate on the air performance of the Funcube Dongle under similar conditions that are expected for the reception of the FUNcube satellite. This page will be update regularly until complete.
The receptions below were carried out using an Arrow II hand-held satellite antenna in RF quiet areas (outside big cities).
| Satellite | Transmitter | Recordings |
|---|---|---|
| CUTE-1.7 + APD II | 437.275 MHz, 100 mW CW | Video |
| SEEDS-II | 437.485 MHz, 90 mW CW | Video |
| SWISSCUBE | 437.505 MHz, 100 mW CW / 1W FSK | Video |
| ITUPSAT-1 | 437.325 MHz, 100 mW FM CW | Video |
| BEESAT | 436.000 MHz, 100 mW CW / 500 mW GMSK | Nothing heard so far. |
| KKS-1 | 437.385 MHz, ??? mW CW | Video |
| PRISM | 437.250 MHz, 80 mW CW | Video |
| FO-29 | 435.795 MHz, 100 mW CW | Video |
| VO-52 | 145.860 MHz, 1W SSB/CW | |
| HO-68 | 435.790 MHz, 200mW CW | Video |
| AO-51 | 435.150 and 435.300 MHz, FM |
Other receptions carried out using standard VHF/UHF stationary beam antennas.
To be added…
Today I have spent some time trying the Funcube Dongle with Quisk SDR. The setup procedure was quite painless and the results very satisfactory: Using an Arrow II hand-held yagi connected directly to the FCD I could receive the HO-68 CW beacon with very good SNR.
It looks like AMSAT is going to launch a new satellite! ARISSat-1 – the successor of SuitSat-1 – is ready to be launched on Progress-41P heading to the International Space Station on Friday, January 28, 2011. It will be deployed into its own orbit during EVA 27 currently scheduled for February 16. Once in orbit, it will slowly decay and eventually burn up in the Earth’ atmosphere. SuitSat-1 decayed after 7 months in orbit and that’s also a likely life time for ARISSat-1.
So, why is ARISSat-1 cool and why should we care?
Continue reading “ARISSat-1: Why is it cool and why do we care?”
Video recording of the HO-68 / XW-1 Chinese amateur radio satellite in linear transponder mode on November 9, 2010. Recorded using the Universal Software Radio Peripheral (USRP) with RFX400 daughterboard and GNU Radio software receiver.
Continue reading “HO-68 / XW-1 linear transponder with GNU Radio, USRP and RFX400”
The slides from my presentation about GNU Radio and the Universal Software Radio Peripheral given at the AMSAT UK colloquium on August 1, 2010. A video recording is also available at http://www.batc.tv/ under archived videos. Continue reading “GNU Radio presentation”
On Saturday 10 July 2010, I have recorded this pass of VO-52. It is the linear transponder downlink between 145.875 and 145.925 MHz. I really don’t understand why people get so crowded in the middle of the passband when there is 50 kHz to play with. Continue reading “VO-52 satellite with GNU Radio, USRP and WBX”
On July 11, 2010, a total solar eclipse could be observed in the southern Pacific Ocean. During the eclipse, the AO-51 amateur radio satellite was entering daylight, coming in over South America.
When AO-51 enters daylight the solar arrays start charging the batteries. This can be observed in the telemetry as a sudden increase of the current from the solar arrays. This time; however, a sudden drop in the current was observed shortly after the current started to increase, see the graph below.
The time and place where this unexpected drop occurred suggested that the satellite might have experienced the solar eclipse that was about to happen over the southern Pacific. It was Masa san, JN1GKZ, who noticed this and reported it on the AMSAT BB where after Mark, N8MH sent out the telemetry graph shown above.
A quick simulation using the Celestia space simulator confirmed that this was indeed the case. The video below shows how it may have looked like from the satellite.
Watch on Youtube or download H.264 encoded .mov file (~100MB).
You can try it for yourself. Celestia is available as free download from http://shatters.net/celestia – it’s a great space simulator for demonstration and educational purpose. You will have to add the data for the satellite. You can use my data to begin with, download from here: http://files.oz9aec.net/video/SolarEclipse/ao51.zip
Unpack the ao51.zip file to the “extras” folder of Celestia, start the program and find AO-51 (type ENTER, AO-51, ENTER, then press “g” to go to the satellite). Enjoy!