First on the air tests of gqrx

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.

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Satellite receptions with the Funcube Dongle

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…

Funcube Dongle with Quisk SDR

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.

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ARISSat-1: Why is it cool and why do we care?

ARISSat-1 photo 2It 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?

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HO-68 / XW-1 linear transponder with GNU Radio, USRP and RFX400

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.

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VO-52 satellite with GNU Radio, USRP and WBX

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”

The solar eclipse of July 11 – as seen by AO-51

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 – 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:

Unpack the 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!

UNITEC-1 Tracking Report

I’m sorry to report that despite coordinated efforts between Japanese and European teams we have not been able to receive any signal from UNITEC-1 over Europe. Japanese ground stations were able to receive both the orbit determination downlink and the major/minor data downlink during the first pass after launch; however, the signal has been lost during the first mission day sometime between LOS over Japan and AOS over Europe.

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