{"id":13594,"date":"2026-09-21T11:51:43","date_gmt":"2026-09-21T15:51:43","guid":{"rendered":"https:\/\/jeremyclark.ca\/wp\/?p=13594"},"modified":"2026-09-21T18:40:14","modified_gmt":"2026-09-21T22:40:14","slug":"rtl-sdr-for-marmotsat-cubesat_2m","status":"publish","type":"post","link":"https:\/\/jeremyclark.ca\/wp\/telecom\/rtl-sdr-for-marmotsat-cubesat_2m\/","title":{"rendered":"RTL-SDR for MARMOTsat CubeSat_2m"},"content":{"rendered":"\n

Introduction<\/h2>\n\n\n\n

During the past two years I have been able to successfully receive CubeSats CANVAS, ENSO, Veronika and EIRSAT-1 (Ref.1\/4). Recently a new Canadian 3U CubeSat MARMOTsat was launched by SpaceX Transporter 17 on July 7th 2026 (Ref.5<\/a>). MARMOTSat has 3 transmitters in the 10m\/2m\/70cm bands. Technical details are given in Ref.6\/7.<\/p>\n\n\n\n

Equipment Setup<\/h2>\n\n\n\n
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Fig.1 Equipment & Software Setup MARMOTSat CubeSat Reception<\/figcaption><\/figure>\n\n\n\n

Figure 1 shows the equipment setup. I first tried receiving the HF CW transmitter on 10m 29.410MHz. The first attempt I used an open wire antenna down at the Toronto harbour front. The second attempt I used an AlexLoop hf loop antenna from my home QTH. On both occasions I did not receive a recognizable CW signal. Keep in mind that the antennas did not have any appreciable gain. I next tried receiving the VHF CW transmitter on 2m 145.875MHz. As in previous attempts I used SDR# tuned 10KHz below the rx frequency to allow for Dopper Shift and sampled at 250Ksps. I used Gpredict\/SatNogsDB to track the satellite and saved the rx signal when the coverage spot entered my QTH. Initially I was looking for a sinx\/x type of signal and ignored the small pulsing carrier. Later on when I played the signal back I could clearly hear Morse code and then decoding in FLDIGI I received text that this was the MARMOTsat cubesat. <\/p>\n\n\n\n

Signal Capture Sept18th_2026<\/h2>\n\n\n\n
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Fig.2 SDR# Playback Saved BB IQ File Showing Rx CW Carrier<\/figcaption><\/figure>\n\n\n\n
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Fig.3 FLDIGI CW Decode from SDR# BB IQ File Playback<\/figcaption><\/figure>\n\n\n\n
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Fig.4 MARMOTsat CW Decode from SDR# Waterfall<\/figcaption><\/figure>\n\n\n\n

Figure 2 shows SDR# playing back the saved BB IQ file. The file was approx 6min long and the CW carrier makes its appearance at about 2min in. In order to get a good decode on FLDIGI, you have to continually adjust the frequency to compensate for the Dopper shift. Figure 3 shows the FLDIGI decode with key words “MARMOTSAT”…”DIPOLE”…”VA7UVS”…”2 WATT”. Figure 4 shows using the visual SDR# waterfall display along with the rx audio to decode the CW. <\/p>\n\n\n\n

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