FITSAT-1 – Full telemetry decode achieved.

Had an excellent FITSAT-1 pass last night, successfully received nearly three full frames of CW telemetry.

The image above (from the heavens-above.com prediction site) shows a similar pass and illustrates the reception window which is just less than 8 minutes. Each frame of telemetry takes around 2.5 minutes to receive, so I was extremely happy with the results.

Again I recorded the pass using SDR-Radio and played back the doppler corrected IQ file later decoding with the MRP40 program, hear is a small video demonstrating the decoding process.

and this was the resulting telemetry data when run through the analyser program (see previous post).

---------------------------------------
FITSAT-1 NIWAKA Downlink CW Code
---------------------------------------
Input Data------------------
S1 :f00501bb
S2 :88db0101
S3 :02000102
S4 :1e20201f
S5 :1a12aae7
-------S1------
S-mater of 437MHz RX :4.69[V]
Total Voltage of Solar cells :0.1[V]
Total Current of Solar Cells :0[mA]
Voltage of single cell battery :3.65[V]
-------S2------
Current of single cell battery :1054.69[mA]
Voltage of 3 series battery :12.83[V]
Current of 3 series battery :0[mA]
Voltage of 2.5V reference :0.02[V]
-------S3------
Voltage of Solar cell + X :0.07[V]
Voltage of Solar cell + Y :0[V]
Voltage of Solar cell - X :0.04[V]
Voltage of Solar cell - Y :0.07[V]
-------S4------
Temperature of 3 series battery   :2.73[℃]
Temperature of single cell battery  :6.25[℃]
Temperature of +Z side   :6.25[℃]
Temperature of –Z side   :4.49[℃]
-------S5------
S-meter of 1.2GHz RX :0.46[V]
------Timestamp-----
14day 3hour 49min 59sec

I have also uploaded a better recording of the audio.

FITSAT-1 CW Telemetry by nerdsville

Well got 80% of a full FITSAT-1 Telemetry Frame

Earlier today I posted about my latest attempts at receiving the FITSAT-1 Cubesat, the reception hadn’t proved too difficult however actually decoding the morse code was proving difficult!

Having another go with the MRP40 decode software and replaying a recorded IQ wave file from yesterday I successfully decoded 80% of a full telemetry frame!

I also found this interesting pdf file detailing the construction of FITSAT-1 and discovered the 437MHz transmitter is only 100mW. So we have a flying metal cube measuring just 10cm x 10cm x 10cm travelling at approximately 4.5 miles/sec roughly 270 miles above the earth, transmitting with just a fifth of the power of one of those PMR446 hand held walkie talkies that in my experience struggle to maintain a contact over a few hundred meters! Isn’t technology wonderful?

FITSAT-1, TechEdSat and F-1 Cubesats after leaving the ISS

Anyhow this was the telemetry frame, as decoded using a PC program developed by one of the students on the FITSAT team.

—————————————
FITSAT-1 NIWAKA Downlink CW Code
—————————————

Input Data——————
S1 :f01601ba
S2 :8dbd8181
S3 :20001820
S4 :1e202020
S5 :*
——-S1——
S-mater of 437MHz RX :4.69[V]
Total Voltage of Solar cells :0.43[V]
Total Current of Solar Cells :0[mA]
Voltage of single cell battery :3.63[V]
——-S2——
Current of single cell battery :93.75[mA]
Voltage of 3 series battery :11.07[V]
Current of 3 series battery :0[mA]
Voltage of 2.5V reference :2.52[V]
——-S3——
Voltage of Solar cell + X :1.13[V]
Voltage of Solar cell + Y :0[V]
Voltage of Solar cell – X :0.84[V]
Voltage of Solar cell – Y :1.13[V]
——-S4——
Temperature of 3 series battery   :2.73[℃]
Temperature of single cell battery  :6.25[℃]
Temperature of +Z side   :6.25[℃]
Temperature of –Z side   :6.25[℃]
——-S5——
S-meter of 1.2GHz RX :No Data
Timestamp :No Data

Some FITSAT-1 Telemetry Decoded

It was dry and a lovely clear sky last night and I had several opportunities to receive the latest Cubesats.

I made some sight modification to the tripod mounting of the small 70cm Yagi antenna I am using, repositioning the clamp allowed me to secure my Android smart phone behind it. Then by using the Satellite-AR app I was able to hopefully point and track more accurately.

As you can see from this close up, it is quite a useful tool. Selecting the Cubesat catagory in the application, shows the procession of the cluster one after the other. The Cubesats have now spaced sufficiently to allow reception of WE-WISH which is just dropping out of sight as FITSAT-1 is starting its pass.

One thing I hadn’t counted on last night was the very high elevation and I struggled to turn and tilt the tripod quickly enough whilst still viewing the screen on the phone, this will hopefully improve with practice!

Previously to the tripod I hand held the antennas but the drawback with that method was not being able to check and make adjustments on the computer, the tripod at least allows me to maintain reception.

I again received WE-WISH but the signal was too weak and short lived for any reasonable attempt at decoding the SSTV image. FITSAT-1 was however much better, getting relatively clear signals from the CW telemetry beacon, however I have been struggling to actually decode the messages, however after some research I tried the MRP40 Morse Code Decoder program, which appears to be excellent and as you can see from the screenshot below successfully decoded some of the telemetry messages. 

Definitely got the bit between my teeth now, will try to get a full telemetry frame this evening, weather permitting!

WE-WISH and FITSAT-1 Received

The recently released Cubesats were due to pass with high elevation late last evening, so the new antenna was mounted out in the garden on a tripod and the FUNCube Dongle connected to the trusty laptop in the shack.

The Cubesats FITSAT-1, WE-WISH and TechEdSat are now supported by the Satellite-AR application on my android phone allowing me a reasonable chance at tracking them.

According to the tracking data the WE-WISH Cubesat is ahead of FITSAT-1 on the orbit, so my first attempt was to capture some of the Infra-Red SSTV imagery it is sending back, I did managed to receive the signal as you can see on the waveform below, you will also see SDR-Radio was preforming doppler correction very well  indicated by the slanted central IQ spur and local ‘carrier’ in the middle of the transmission (was playing back a captured IQ wavefile) Sadly the WE-WISH signal wasn’t strong enough and didn’t last long enough for any meaningful decode, but I was able to confirm that instead of being at 437.505MHz it is nearer 437.514MHz as was reported on AMSAT-UK

WE-WISH Downlink Transmission, received in UK 16-OCT-2012 19:32UTC

I was very happy to have received this as the WE-WISH downlink transmitter is reported to be only 100mW! As the signal disappeared I quickly switched to the latter stages of the FITSAT-1 pass and got some nice clear bursts of the CW beacon.

FITSAT-1 Downlink Transmission, received in UK 16-OCT-2012

Tonight there are two other nice high elevation passes of the Cubesat cluster, so hopefully will get out to have another attempt.