Last week I wrote a post with a study about the QO-100 WB transponder power budget. After writing this post, I have been talking with Dave Crump G8GKQ. He says that the main conclusions of my study don’t match well his practical experience using the transponder. In particular, he mentions that he has often seen… Continue reading More about the QO-100 WB transponder power budget
Results for "QO-100"
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Measuring the QO-100 WB transponder power budget
The QO-100 WB transponder is an S-band to X-band amateur radio transponder on the Es’hail 2 GEO satellite. It has about 9 MHz of bandwidth and is routinely used for transmitting DVB-S2 signals, though other uses are possible. In the lowermost part of the transponder, there is a 1.5 Msym QPSK 4/5 DVB-S2 beacon that… Continue reading Measuring the QO-100 WB transponder power budget
Monitoring the QO-100 WB transponder usage with Maia SDR
I am interested in monitoring the usage of the QO-100 WB transponder over several weeks or months, to obtain statistics about how full the transponder is, what bandwidths are used, which channels are occupied more often, etc., as well as statistics about the power of the signals and the DVB-S2 beacon. For this, we need… Continue reading Monitoring the QO-100 WB transponder usage with Maia SDR
More QO-100 orbit determination
In a previous post, I showed my orbit determination experiments of the GEO satellite Es’hail 2 using the beacons transmitted from Bochum (Germany) through the QO-100 amateur radio transponder on-board this satellite. By measuring the phase difference of the BPSK and 8APSK beacons, which are spaced apart by 245 kHz in the transponder, we can… Continue reading More QO-100 orbit determination
QO-100 orbit determination
In a previous post, I showed my experiment about measuring the phase difference of the 8APSK and BPSK beacons of the QO-100 NB transponder. The main goal of this experiment was to use this data to do orbit determination with GMAT. Over the last week I have continued these experiments and already have started to… Continue reading QO-100 orbit determination
Calculating the QO-100 beacons frequency separation
In my previous post I set out to measure the phase difference between the QO-100 8APSK and BPSK beacons. One of the things I mentioned is that the frequency separation between these two beacons was approximately 1.6 Hz larger than the nominal 245 kHz. A frequency error of a couple of Hz is typical when… Continue reading Calculating the QO-100 beacons frequency separation
Measuring the QO-100 beacons phase difference
Since a couple months ago, the QO-100 NB transponder has now two digital beacons being transmitted continuously: the “traditional” 400 baud BPSK beacon, and the new 2.4 kbaud 8APSK multimedia beacon. This transponder is an amateur radio bent-pipe linear transponder on board the Es’hail 2 GEO satellite. It has an uplink at 2400.25 MHz, a… Continue reading Measuring the QO-100 beacons phase difference
Decoding the QO-100 multimedia beacon with GNU Radio: part II
In my previous post I showed a GNU Radio demodulator for the QO-100 multimedia beacon, which AMSAT-DL has recently started to broadcast through the QO-100 NB transponder, using a downlink frequency of 10489.995 MHz. This demodulator flowgraph could receive and save to disk the files transmitted by the beacon using the file receiver from gr-satellites.… Continue reading Decoding the QO-100 multimedia beacon with GNU Radio: part II
Decoding the QO-100 multimedia beacon with GNU Radio
Last weekend, AMSAT-DL started some test transmissions of a high-speed multimedia beacon through the QO-100 NB transponder. The beacon uses the high-speed modem by Kurt Moraw DJ0ABR. It is called “high-speed” because the idea is to fit several kbps of data within the typical 2.7 kHz bandwidth of an SSB channel. The modem waveform is… Continue reading Decoding the QO-100 multimedia beacon with GNU Radio
LDPC code design for my QO-100 narrowband modem
A couple months ago I presented my work-in-progress design for a data modem intended to be used through the QO-100 NB transponder. The main design goal for this modem is to give the maximum data rate possible in a 2.7 kHz channel at 50 dB·Hz CN0. For the physical layer I settled on an RRC-filtered… Continue reading LDPC code design for my QO-100 narrowband modem