DTUsat-2 Telemetry Analysis 2.4GHz #1

National Space Institute at the Technical University, Denmark
Uplink 1268.900MHz 9k6 CPFSK / Downlink 2401.835MHz 1k2,19k2,38k4 MSK

1 40030U 14033W   15194.69001683  .00001763  00000-0  20355-3 0  9996
2 40030 097.9487 094.7124 0013857 090.4655 269.8149 14.86856151 57728

DTUsat-2 Launch Event

Decoding of the Morse beacon

Received at 16:11:30 UTC, 29 May 2015

Morse Code of this wav file
The values are 16 bit long, but the preceding zeroes are not transmitted.

Telemetry Analysis

  Status bits: 100
  Radio temperature: 10101010000=1360

  Battery temperature: 10101010000=1360

  Battery voltage: 1011110110=758
  Beacon count: 0


(C)DTUsat Project

Re: Re^2: L band transmit, S band receive.
To: Mineo Wakita (JE9PEL)
Date: Tue, 14 Jul 2015 23:22:05 +0000 (UTC)


Here is what I know and have observed about DTUsat-2. I have been
recording audio of the passes for two months. Beacon is 200mW, signals
are very strong, and do not fade. I copied it easily with a single 20 
turn helix. It's a good signal to test tracking on 2.4 GHz.

Battery power has failed. Downlink only during eclipse using power from
solar panels. DTUsat-2 appears at all locations either once or twice at
about 11 AM local time and again about midnight. It is sun synchronous.

The CW beacons can be every 30 seconds apart or one minute apart depending
if the on board computer (OBC) is running. If the OBC is running, the
first three bits following the CW I.D. will be "dash-dot-dot" or 100.
If the three bits following the I.D is "dot-dot-dot" or 000, the OBC is
powered but not running.

When the OBC is running, CW beacons may be 1 minute apart with a tone
sounding mid way between beacon intervals. Downlink may be a full CW
beacon, partial CW beacon, a tone, or a missingsignal for that interval.

The beacon CW coded message following the I.D is broken into five segments
which is STATUS, Radio Temp, Battery Temp, Battery Voltage, and Beacon
Count. Beacon count, the last segment, is the "number of beacons since
the last full system reboot". This number can be a "dot" which is zero up
to a large number, for Example: "Dash Dash Dot Dot Dash" which is 25.
To me, a good condition would be a Status of 100 with a Beacon Count 30.

I do not know the sat's commands. I think an attempt will be to design
a PING command for use from different locations around the globe and
attempt a response from DTUsat-2. A contest has been discussed.

Please post this on your blog as the DTUsat team would like amateur radio
help. Below is a history of my emails with DTU. Oldest is at the bottom. 

Rene Fleron is the project manager. He is on vacation until July30th.
Please email him, he would be pleased to hear from you.

I have no L uplink, only S band receive.

73, Mike (K9QHO)

Supplement (JE9PEL, L-band and S-band system)
HGL-1232 (MAKI), 1200MHz Loop (32ele x 2, 24dBi)

HGL-2429 (MAKI), 2400MHz Loop (29ele x 1, 21dBi)
Converter: Drake2880, 2400MHz -> 144MHz




DTUsat-2 controlled frequency by JA5BLZ, JA0CAW on 16Aug2015

DTUsat-2 IQ.WAV analyzed by JA0CAW, JE1CVL on 28Aug2015

DTUsat-2 MP3 received by JO1PTD, JE9PEL on 21Sep2015


DTUsat-2 report by DD1US

DTUSat-2 (Danish Technical University Satellite-2) was launched together
with 36 other satellites on a Russian Dnepr rocket on Thursday, June
19th 2014 at 19:11h UTC from Dombarovsky in Southern Russia. Its primary
mission is bird migration monitoring and tracking.

The uplink is at 1268.900 MHz in 9.6kbit/s CPFSK modulation. The downlink
is at 2401.835 MHz (some have reported 2401.842 MHz) with an output power
up to 220mWand features several modes: A CW beacon (30 bit/s OOK) with
220mW output power using the callsign OZ2DTU is repeated ever 30 or 60
seconds (depending on OBC is running or not ). Alternatively the downlink
can be switched also to transmit data in 1.2kbit/s, 19.2kbit/s and
38.4kbit/s MSK modulation.

Enclosed CW and MSK signal was received on August 28th 2015 at 09:27:40
UTC on 2401.840 MHz by DD1US. One can clearly hear the beacon transmiting
OZ2DTU followed by the bits 100100100. Finally a short MSK transmission.
The signals were demodulated in AM and FM because CW is best audible in
AM whereas MSK is audible only using an FM demodulator. (by DD1US)

Because I, JE9PEL couldn't adjust the crystal in Drake2880, I replaced to
GRX-2402D. System: HGL2429(Loop 29ele), GR-2400(Amp), GRX-2402D(Converter)

  My_Antenna 2.4GHz View


The attempt of 2.4GHz reception from DTUsat-2 was passed two months. Finally I could receive this signal at 00:35 UTC, 23 Sep 2015. This reception was the many hardship for me. The nominal frequency was 2401.835MHz, but the received frequency in this time was around 2401.843MHz. Because the doppler shift is large that +-54kHz, it's hard to identify the frequency while turning the knob of the radio. So very fast CW of DTUsat-2, I remembered USB carrier signal such as UO-11, AO-16, and AO-40 satellite. 00:35-00:47 UTC, 23 Sep 2015, Ele 33 SE-E-N, around 2401.843MHz CW(USB) System: HGL2429(Loop 29ele), GR-2400(Amp), GRX-2402D(Converter), TS-790S GRX-2402D Converter: adjusted to 2401.843MHz -> 145.843MHz http://www.dropbox.com/s/sr7qxljmdba1cab/50923dt2.wav?dl=0 DTUsat-2, 9:22-JST on 22Sep2015, Ele24deg Spectrogram16 - Function - F1_Scan_Input I don't hear anything yet. Nominal frequency=2401.835MHz Actual frequency =2401.843MHz +/-54kHz doppler
sdrtocal.xls Excel file using with CALSAT32
I think that it is trying to reception by FCD+SDR# in the future, but now I have set the frequency by hand to TS-790S (KENWOOD). The frequency is computed in real-time Doppler shift using the Excel file that I wrote, which is synchronized with CALSAT32, the tracking software. I set by hand the frequency to see the calculated frequency instantly. The nominal frequency of DTUsat-2 is 2401.835MHz, but I feel like that is around 2401.843MHz. This frequency is not accurate because I observe in the large Doppler Shift. I'm seeking now the information about the exact frequency. According to the received report, it's no the signal transmission at the high elevation, and CW reception is easy at the elevation of 20 degrees after AOS or before LOS. K9QHO's antennas Re: Re^2: DTUsat-2 2.4GHz received ! From: Michael To: Mineo Wakita Date: Mon, 28 Sep 2015 23:23:38 +0000 (UTC) Hello Mineo, Thank you for the email. I have attached a photo of my antennas. Please try SatPC32 to control your TS790S by computer. A fully operational demonstration version is at: http://www.dk1tb.de/downloadeng.htm Total Doppler is 100 KHz over complete pass on 2.4GHz. Manual tracking is difficult. I believe your calculation of 2401.843MHz is very near correct. It is not 2401.835MHz. I am using a surplus AIDC 3733 downconverter at the antenna. I get a down conversion error. For example, the outside temperature at my QTH changes 10C to 21.1C from 8:00 AM to Noon. This affects the crystal at the antenna. At 13.3C, my center frequency is 2401.838MHz, but at 21.1C, my center 2401.841MHz. I sample the temperature, then I change the center frequency inside the program. I am sure your new converter does not have this problem. 73, Mike, K9QHO ----- Original Message ----- Subject: Re^2: DTUsat-2 2.4GHz received ! From: Mineo Wakita To: Michael Sent: Saturday, September 26, 2015 10:27:23 PM Hello Mike, K9QHO. My 2.4GHz system: HGL2429(Loop 29ele), GR-2400(Amp), GRX-2402D(Converter), TS-790S Converter Example: 2401.850MHz -> 145.850MHz I have set the frequency by hand to TS-790S (KENWOOD). The frequency is computed in real-time Doppler shift using the Excel file that I wrote, which is synchronized with CALSAT32, the tracking software. I set by hand the frequency to see the calculated frequency instantly. The nominal frequency is 2401.835MHz, but I think that is around 2401.843MHz. This frequency is not accurate because I observed in the large Doppler Shift. Do you know the exact center frequency? Do you receive by setting the frequency to what MHz? JE9PEL, Mineo Wakita --------------------------------------------------------------------- Michael has shared 3 items with you From: Michael To: Mineo Wakita Date: Mon, 28 Sep 2015 19:37:49 -0400 Michael L Williams has shared 3 items with you. View it here: ****** The three items are: 1. Typical audio file of DTUsat-2 dated September 28. This section runs from 2:30 to 6:30 of the pass. Partial beacon at 0:29, 2nd partial beacon at 1:00. Full beacons at 2:02, 2:33, 3:13. 2. Printed summary of pass. The audio file contains the partial beacons at 2:59, 3:30 and full beacons at 4:33, 5:03, 5:43 on the summary sheet. 3. Video of SatPC32 controlling Turning on FT-847 for Doppler of DTUsat-2 on 2.4GHz. 73, Mike --------------------------------------------------------------------- DTUsat-2 2.4GHz Telemetry Analysis I, JE9PEL tried to analyze DTUsat-2 2.4GHz signal that K9QHO received on 28 Sep 2015. When you replay 3:13 point in this audio wav file, you will find that it's a beautiful tone to follow the doppler shift. http://www.dropbox.com/s/dpogot4ehx17mh5/50928dtu.wav?dl=0 DTUsat-2 frequency finally found In this mornig (09:56 JST, 9 Oct 2015), I found at last the exact transmitting frequency of 2.4GHz signal of DTUsat-2. I could receive many times its 2.4GHz signal from DTUsat-2 immediately after AOS. The value was currently 2401.848MHz in my equipment. I will continue to improve to be able to receive it reliably. 09:56-10:08 JST (00:56-01:08 UTC), 9 Oct 2015, Ele 58 SE-E-N, 2401.848MHz CW http://www.dropbox.com/s/zk5qgc3keftpgw9/51009dt2.wav?dl=0 DTUsat-2 visualized using FCD-SDR# I could receive and visualize for the first time using FCD-SDR# at 01:04UTC, 24 Oct 2015. In consideration of approximately +/- 50kHz Doppler shift of the received frequency changes to from 2401.898 to 2400.798 MHz, ie. from 145.898 to 144.798 MHz. 01:04-01:16 UTC, 24 Oct 2015, Ele 70 SSE-E-N, 2401.848MHz USB http://www.dropbox.com/s/7rshpaowxf5ljhu/51024dt3.wav?dl=0 I can now reliably receive the signal of 2.4GHz (2401.843MHz) from DTUsat-2 in this system. I could receive five signal in the path of 01:17-01:29 UTC, 25 Oct 2015. I must receive in until three minutes after AOS in any path. It becomes difficult to hear 2.4GHz when the elevation angle is becoming high. And I am trying to hear the signal 2.4GHz (2404.030MHz) from LQSat several times, but I will not be able to confirm the signal. (I have successfully received LQSat signal at a later date.) ARC-1 in addition to DTUsat-2 and LQSat seems to send 2440.500MHz signal. Because ARC-1 is unknown the orbital element, I can't track ARC-1 satellite. I estimated definitely the center frequency was 2401.843MHz in my equipment. The value of the Downlink frequency, etc. in Excel file has all automatic calculation in synchronization with Calsat32 program. (Manually frequency setting in SDR#) The following figure shows the appearance of the first CW beacon in today's reception. Its value is related as follows. 01:40-01:52 UTC, 3 Nov 2015, Ele 41 S-W-WN, 2401.843MHz USB Center + Doppler = Downlink -> Converter = SDR#Frequency(USB) 2401.843 + 0.054 = 2401.897 -> 145.897 = 145.897 DTUsat-2 analyzed at last Finally I could analyze using a signal that myself received. 00:57-01:09 UTC, 7 Nov 2015, Ele 56 SE-E-N, 2401.843MHz USB http://www.dropbox.com/s/4k4dpj0gker30cb/51107dt2.wav?dl=0 DTUsat-2 2.4GHz received at TCA 01:07-01:19 UTC, 15 Nov 2015, Ele 74 SE-E-N, 2401.843MHz USB I first received a very strong CW signal at TCA in this path. From the reception experience until now, I had been understood to be able to receive DTUsat-2 only when it was lower than 20 degrees of the elevation angle when AOS or LOS. However, I found that it is possible to hear the signal of 2.4GHz even TCA. When a strong signal has been heard at TCA, I thought a signal of UFO or something. In SDR#, I always see the thin white line, but in this pass I could see definitely the three white lines of DTUsat-2 specific in the figure below. And I received the total 5 times which was 3 times at AOS and 2 times at TCA. In the any path I felt the need to observe carefully the signals between AOS-TCA-LOS. 00:50-01:02 UTC, 21 Nov 2015, Ele 44 SE-E-N, 2401.843MHz USB I can hear stably the signal of DTUsat-1 2.4GHz in the morning. In the today morning, I received three compete frame and a half of the piece. I see the two signals in the FFT screen of SDR # in the figure below. DTUsat-2 in night > Subject: DTUsat-2 in night > From: JE9PEL > Date: 17 Nov 2015 > > I do not hear DTUsat-2 in the night. > I can hear only in the morning path. Re: DTUsat-2 in night From: MICHAEL To: Wakita, Mineo Date: Fri, 20 Nov 2015 18:29:21 +0000 (UTC) DTUsat-2 has no battery power. It is powered only by solar panels. In winter, it is in eclipse over the north pole and is not powered. DTUsat-2 has no solar panels on Z axis. I think when it passes under sun in the southern hemisphere, it goes through a power down and computer reset. 73, Mike (K9QHO) (C)DK3WN, JE9PEL, DTU DTUsat-2 ping instructions Subject: DTUsat-2 ping instructions From: MICHAEL Date: Tuesday, December 1, 2015 7:41:38 PM I thought you might like to send an uplink signal to DTUsat-2 and attempt to receive a response. Could you put this on your blog as others may want to do this. Please see email from DTU below. Subject: Termination of reception reports From: DTUsat-2 Ground Station Date: Mon, 30 Nov 2015 21:33:07 +0000 Thank you for all your reports. I have finally managed to get our SW engineer craft a bit-string which pings the satellite, attached. You may share it with anyone as you please. So the status is that we still hear the beacons here, but no 100 status unfortunately. However a Japanese radio amateur, JA0CAW, has also reported 100 status. That actually ads a little bit to the confusion, but hopefully it'll make sence once I get going writing up my paper. ----- [Attached text from Project Manager] ----- DTUSat-2 Failsafe Command The last line of this file provides the binary encoding of a DTUSat-2 failsafe mode command. Command: PING (with empty contents) Acknowledgement requested: No Response requested: Yes Expected response: Generic telemetry response packet (with empty payload) Audible response (AM): One long beep [600 Hz, 1.33 sec (at default preamble size)] Carrier: 1.2689 GHz Modulation: FSK Deviation/swing: +-25 kHz (0: -25, 1: +25) Baud rate: 9600 bits/s Subject: Re: DTUsat-2 ping instructions From: Mineo Wakita, JE9PEL Date: Wednesday, December 2015 6:39:03 AM I put your mail about DTUsat-2 ping instructions on my web page. I do not understand whether to send what ping command to the satellite. Thank you. DTUsat-2 heard 10 times 00:51-01:03 UTC, 13Dec2015, Ele 45 SE-E-N, 2401.843MHz USB I heard the signal of DTUsat-2 10 times in this pass. This is my best record. It should be avoided to receive in the middle of the FFT screen of SDR#, but I could not be adjusted it because the Doppler shift of the frequency is greater. I heard the signal of 2.4GHz until near LOS.
DTUsat-2 in old and new fusion system 01:34-01:47 UTC, 31 Dec 2015, Ele 53 S-W-WN, 2401.843MHz USB I heard DTUsat-2 2.4GHz signal using "WinXP + FCD + SDR#1327" system. DTUsat-2, spectrum width I found the width of 18.5kHz signal from the center frequency of 2.4GHz can be seen to the left and right. I confirmed that occurred several times this phenomenon from the other day. I do not know what it is.

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