QSL from Delfi

Today a surprise in the mail, I have received two QSL cards from the Delfispace team. Thank you very much and I hope the satellite building tradition will continue in the coming years. The next satellites will be Delta and Phi (DelFFi) and the launch is scheduled for next year.





Delfi-n3Xt one year in Orbit

Dear Radio Amateur Operators,

Delfi-n3Xt ModelDelfi-n3Xt is now in orbit for 1 year. We have been able to demonstrate the T3µPS micro-propulsion payload and the ITRX transceiver payload and have executed the a-Si:H solar cell experiment. We have also tested many of the CubeSat bus advancements: the electrical power subsystem with the battery system, robust command and data handling and an advanced attitude determination and control subsystem, comprising our custom-developed reaction wheels, magnetorquers and sun sensors. Analysis has proven that many systems and components performed as expected, while for some lessons are drawn to improve upon in the future. This shows the great achievements on the technical objectives of the mission. Last but not least, Delfi-n3Xt has trained over 80 students on a real satellite project and many of those students have now entered a professional career in the space sector. After 3 months, Delfi-n3Xt has achieved its ambitious primary mission objectives and we have concluded on a mission success!

After three months of operations, we have unfortunately lost contact with the satellite after an experiment with a transponder module for radio amateurs. We have performed many attempts to recover from this situation, but they were not successful so far. Despite of this, Delfi-n3Xt is a successful mission and also is a good and solid foundation for future space engineering projects like the current DelFFi mission. DelFFi is a formation flying demonstration mission with two identical 3U CubeSats developed at TU Delft and is part of the QB50 project in which the thermosphere is going to be characterized by 50 CubeSats carrying a standard sensor suite for in-situ atmospheric measurements. This ambitious mission will push our Delfi roadmap one step further. Delfi-n3Xt acts as a stepping stone towards this mission, and many technical elements have found their way in the DelFFi design.

We would like to thank all radio amateurs for helping us by receiving data of Delfi-n3Xt.

Source: J. Bouwmeester, Delfi CubeSat Program Manager

Delfi-n3Xt help on S-band reception

Delfi-n3Xt: Request for help on S-band reception

Dear all,

It has been a while since you heard from us. We are still having problems to receive our satellite since our transponder test. We now want to try something different: trying to activate our S-band transmitter and let it transmit at full power for a pass. If we are able to receive a signal from the S-band, we know that Delfi-n3Xt still has an operational receiver and we could potentially demodulate the S-band signal. But since we already know that the latter is Delfi-n3XT Cut Outdifficult, the first focus is just to “see” the signal. Since the satellite is still tumbling, it is a matter of link budget and statistics if we are able to catch the signal. To increase our chanceswe would like to ask the help of radio amateurs in the neighbourhood with suitable equipment. Since we have to actively command the satellite we have planned the passes which are suitable for the Netherlands, Germany, Belgium and Northern France and the availability of operators from our side. According to a quick survey, you are living in the area in reach at the selected passes.

The question to you:

Do you have S-band (2405 MHz) reception functionality with a dish of at least 2.5 meter and tracking capability and willing to follow and record one or more passes for us?

If so, please let us know your location, the gain of your antenna and the passes you are able to follow. Off course you do not have to be actively present during the pass. You can just record it and send the recording later through www.wetransfer.com.

Delfi-n3Xt will send at 2405 MHz +/- 100 kHz. The latter is the worst case uncertainty band, but I expect it to be pretty close to the right frequency. If you have an SDR, you can best set it at +/- 1 MHz around the centre frequency. Off course you do not have to be actively present during the pass. You can just record it

The planned attempts are stated by the LOCAL time of commanding below. If successful transmission would be within the 10-20 minutes after the indicated time.

  • Tue 13-05 ~11.25h local time
  • Wed 14-05 ~12:00h local time
  • Thu 15-05 ~22:10h local time
  • Fri 16-05 ~11:35h local time
  • Sat 17-05 ~12:10h local time

If you are able, your help is highly appreciated!

Vy 73,
Jasper (PC4JB)

Delfi-n3XT Some Bad News

Despite earlier messages there are no signals received from Delfi-n3Xt. It seems that the signals that where believed to be Delfi-n3XT where signals from Delfi-C3. Below a message I received from Jasper PC4JB.

Delfi-n3XT Cut OutUnfortunately, we have not heard anything from Delfi-n3Xt since Thursday 20/02 after our transponder test. During the transponder test we could hear our side beacon at 145.870 MHz and we were still able to switch back to normal transmission an back to transponder again (and also received the beacon the second time). Nothing seemed to be wrong, except for the transponder itself not properly working. The satellite was supposed to return to nominal operations in the next orbit.

We think that a hardware failure occurred either at the second half of the transponder orbit or during the mode switch. Since Friday we have made many attempts to revive the satellite. Since we have an independent radio, there was (and still is some) hope to get the satellite back in transmission. There are however a few points were common mode failures could occur: the phasing circuitry which connects both transmitters and an I2C buffer at the main bus side. We do however still have some hope that only one radio has failed and that we might still be able to command the satellite to use the other. Since all trivial command schemes did not work, next week we will only focus on a specific test to turn the transmitter on for a brief moment. During the weekend we saw some narrow band signal at 10 kHz below 145.870 MHz (+/- Doppler), which might potentially be related to the local oscillator. If we can reconstruct this a few times and clearly correlate this to Delfi-n3Xt (we do have a lot of intermitting noises sources in the neighborhood) we at least know the OBC and one radio is still working and we can commence to next steps.

We appreciate everyone’s help to listen to Delfi-n3Xt to see if there is still some signal left. I think the best changes (besides Delft passes in which we try to command) are when the satellite comes just out of eclipse and is supposed to startup one of the transmitters. Please note that it has become very crowded with CubeSats lately, so any signals which are off in frequency (except for the -10 kHz tone), have a very different bandwidth and/or Doppler shift are very likely to be other satellites in the neighborhood. Today we had for instance Delfi-C3 almost perfectly aligned sending at the same frequency. Delfi-n3Xt will only transmit at about 145.870 MHz.

[PE0SAT Thanks Delfi-n3XT ground station for the above information]

Delfi-n3XT Transponder test

Coming, Delfi-n3XT Linear Transponder tests

Delfi-n3Xt Earth

We are going to test the transponder functionality of Delfi-n3Xt this week. I have to be honest that this functionality was implemented last minute on the satellite and was only tested briefly in a non-representative setup. I therefore estimate the chance that it will work at 50/50.

Our first series will be at:

  • Thursday 20-02-2014 at about 10:50 UTC
  • Friday 21-02-2014 at about 9:50 UTC
  • Friday 21-02-2014 at about 11:25 UTC

After a few initial tests, and provided that it works, you are free to use the transponder for communication. We will leave it in this mode for the remainder of the sunlit part of the orbit, so only in Europe and Africa it is possible to use this mode for now. If successful we will turn on the transponder more often and for longer periods of time such that everyone can enjoy it.


Uplink 435.530 – 435.570 MHz LSB Linear transponder
Downlink 145.880 – 145.920 MHz USB Linear transponder (inverting)

1 39428U 13066N   14038.63217054  .00002453  00000-0  43939-3 0   699
2 39428  97.7772 111.8003 0129782 303.2748  55.6102 14.62338302 11392

Source: PC4JB, Jasper Bouwmeester, Delfi Nanosatellite Program Manager

Delfi-n3XT Telemetry

Delfi-n3XT Telemetry 11-01-2014 10:09 UTC

Decoded with Maspro UHF yagi, SSB preamp, FUNcube Dongle Pro+, SDR# and DUDE Delfispace ground station telemetry decoder. After that the raw packet data was used as input for one of the nice decoder software packages from Mike DK3WN.

Delfinext 11-01-2014 10:09UTC

The latest versions of the software packages from Mike come with a save function that makes a transparent screenshot from the software output. A very nice new feature. Thanks Mike.