Category Archives: packet

More PhoneSat pictures and other packets

Had chance to process the 14:05BST PhoneSat pass IQ file and have got some more image pieces (again I have scaled them up from the original 20 x 15 pixel size)

Also decode a few more data packets,  from Graham and Bell the PhoneSat 1.0 Satellites

Also got a sensor packet from Alexandra (the PhoneSat 2.0 Beta Satellite)

These packets not be encoded; and are plain ASCII characters. There are 5 types of packet:

Sensors from the phone

  • Time: unix time time in milli seconds.
  • Reboot: number of reboots of the phone.
  • Counter: number of packets sent since the beginning of the mission.
  • Packet type: for this packet will be sensors from the phone (1).
  • Phase: phase in which the satellite is (we have 3 phases).
  • Compass: magnetic field value for X, Y, Z axes from the phone sensor in nanoTesla.
  • Gyro: spin rate for X, Y, Z axes from the phone sensor in deg/sec.
  • Accel: accelerometer value of X, Y, Z axes from the phone sensor in m/sec2
  • Format: [Time, Reboot, Counter, Packet Type, Phase, CompassX, CompassY, CompassZ, GyroX, GyroY, GyroZ, AccelX, AccelY, AccelZ]

My packet was

So 1262348062776 milliseconds (this doesn’t look right, gives 01 January 2010 12:14:23!)
Reboot number 11
489 packets
Packet type 1
Phase 3
Compass X = 30.4, Y = 38.8, Z = 13.2
Gyro X = 80.2, Y = -5.7, Z = -68.5
Accel X =  -0.5, Y=  0.1, X= -0.6

First Phonesat Image Piece

Before leaving for work this morning I set up the 70cm yagi on the tripod pointing due south at around 45 degrees inclination and my ancient laptop with the original FUNCube dongle, hoping to catch some more PhoneSat packets during this afternoons passes, the first at 12:30BST, the other around 14:05BST.

I was hoping to be home for the later one, but unfortunately I was held up and wasn’t, luckily I was able to set both of them to record by logging in remotely. But due to the fixed antenna meant I only was able to get the optimum signal for part of the pass.

Still I grabbed the file for the first pass and was able to analyse the resulting IQ file during a coffee break and successful decoded a handful of packets.

I was especially eager to see the result as in my mailbox this morning was a message from the PhoneSat team

Let the puzzle begin

As scheduled, Graham and Bell have just started transmitting picture packets, so please stay tuned to your radio. Since the picture packets need to be stitched to restore the complete Earth picture, we will need as many packets as possible. Ultimately a new page will be created to display the current construction of the pictures. Let the puzzle begin!

Best regards,
The PhoneSat team

Indeed one of the packets was an image piece, however my excitement was quickly tempered when I discovered it was infact just 20 x 15 pixels in size!

fm KJ6KRW-2 to CQ-0 via TELEM-0 UI  PID=F0

Produced this image, which I have scaled up to 200 x 150 pixels! A hint of blue, cloud and land?

The picture packets are decoded as.webp pictures. These pictures can be converted into png pictures using Google’s webp converter.

All three Phonesats received and decoded

Yesterday the delayed Antares rocket launched and successfully deployed the three Phonesats

After downloading the TLE this morning and checking the orbital prediction I found as luck would have it that a decent pass would occur when I am home during my lunch break.

So it was out with the 70cm yagi on the tripod fixed pointing south at around 45 degrees elevation and my older FUNCube Dongle on the laptop running SDRSharp (SDR#). It was pleasant sitting on the bench at the top of the garden in the sunshine with the dogs eating my lunch waiting for the pass, and yes at around 14:17BST (13:17UTC) I started to get signals, which came in very strongly.

I recorded the IQ file for later analysis and decoding

I originally tried decoding using Multipsk which I have used extensively to decode APRS from the International Space Station but wasn’t having any luck so I downloaded the free and simple to use Qtmm AFSK1200 Decoder, I simply feed it the audio (using virtual audio cable) and it was soon decoding. However I did have to widen the bandwidth quite a lot to accommodate the full signal. 

The resulting decodes were saved into a text file, here is a selection

15:35:11$ fm KJ6KRW-2 to CQ-0 via TELEM-0 UI  PID=F0
15:35:45$ fm KJ6KRW-0 to CQ-0 via TELEM-0 UI  PID=F0
15:36:59$ fm KJ6KRW-1 to CQ-0 via TCPIP-0 UI  PID=F0

Note due to quite large doppler shift I had to keep replaying the IQ file to adjust for it and the time shown is the time I decoded it, not the time it was received.

Going to the Phonesat website, you can register and submit the packet data which checks and displays the decoded information, which I did.

I had to discard the first and last decimal point in the data to successfully submit it the website

I also managed some good signals using the discone in the loft.


This week with the launch of the Russian Soyuz TMA-03M spacecraft to the International Space Station it occured to me that I have never seen it pass overhead or indeed made any effort to hear any transmissions from it. So off I went to the website to check the pass predictions for the week and was pleasantly surprised to discover that over the Christmas period there are a number of good evening passes (the potenitally visible ones are also listed on the Guardian website)

There are a multitude of  frequencies to potentially listen to, some of the operational ones could be quite interesting over the next few days, but at first I was interested in some of the ARISS frequencies.

On Tuesday (20th Dec) evening I popped outside with the 2Meter YAGI, Alinco DJ-X10  and my new found Satellite-AR Android App I did manage to see a faint moving point of light briefly as it came up over the horizon, but quickly lost it due to cloud cover and I think it passed into the Earth’s shadow.

I was able to carry on tracking it using the Satellite-AR and picked up some very strong data bursts on 145.825MHz this is the APRS/Packet digirepeater. More details on the ARISS website. APRS in simple terms allows ham operators send a coded data message usually containing their GPS location, call sign and other information. This is received by the digirepeaters and rebroadcast, in the case of the ISS the digirepeater is moving around the earth at nearly 5 miles/second.

Last night (21st Dec) I used the loft mounted antenna and my Realistic PRO-2006 and captured and decoded some of the data on my PC using MultiPSK

Some of the data as it appeared in text form on the screen showing the coordinates, call signs and comments.

@215120h5218.35N/01624.62E-73! via ISS’yI1l -/]Paco en Leganes=
:F6GWB    :ack02!5214.25N/00043.40E`Aprx v2.02 SatGate@215356h5218.35N/01624.62E-73! via ISS=4542.75N/01142.00E`73′ Via ISS de Cris {UISS52}=3919.07N/00259.59E`73′ Via ISS {UISS52}!5310.76N/00532.86E- – 73 – Roland – -`vDjl -`73’s via ISS ea5hzz.raul@gmail.com_” :SP1TMN-6 :73{17 ‘vC$l S]73 FOR ALL=
=4549.52N/01600.66E`[JN85AT] 73 via ISS de Robert – Zagreb – Croatia
!5310.76N/00532.86E- – 73 – Roland – –

  Some more good passes this evening that I might get a chance to capture with YAGI and weather permitting might get to see the point of light as it crosses the sky!