Delfi-n3xt Kaputt

Pues eso. Que se ha roto.
Tras las pruebas de activacion del transponder se ha muerto. Intentan revivirlo, pero ya veremos.

Mensaje original:

Dear radio amateurs,

Unfortunately, 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 neighbourhood) we at least know the
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 neighbourhood. 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.