Update on DELFI-N3XT transponder test

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A follow-up to our previous news on the DELFI-N3XT transponder test was received via e-mail today:

Dear all,

Today we did a first transponder test. We could hear the beacon, but unfortunately did not hear anything back from our calls. Also we were missing the noise floor of the transponder band. Our hypothesis is that our adjustable LO (Si570) which is mixed with the IF band could not be programmed correctly and hence the pass-band goes outside our filtered band (which is a good thing, because we do not want to transmit on illegal frequencies). This LO is adjustable by I2C communication and should be programmed each time at power up (so each time the transponder mode is activated. We will do two attempts more tomorrow at the morning ground passes and even if that doesn’t help we will keep on trying with different settings. If the situation changes I will update you again.

Best regards,

Jasper, PC4JB

DELFI-N3XT update

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delfi-n3xtThe following update was provided today on the DELFI-N3XT satellite launched in November 2013:

Dear radio amateurs,

It has been a while since we have provided an update, so it is time to brief you again.

Delfi-n3Xt Status

The satellite is doing fine and is in healthy shape. We are now almost 3 months in orbit and have fulfilled a major part of the primary mission objectives. This means that we are close to a mission success. This does not mean that everything works flawlessly as there are several subsystems with issues. Given the amount of payloads and new technologies, I can only say that this was to be expected and accounted for in the mission. Delfi satellites are developing platforms and Delfi-n3Xt is an in-orbit test facility. The good thing is that issues encountered are not even a final verdict on the subsystems performance. The attitude determination and control subsystem currently is hampered by a high magnetic noise, but might still be tweaked and tune to see if we can get it to work properly. This however takes some time, so we are glad that the satellite seems to be in healthy state and we can take more time to experiment with it.

DUDe

We are still working on an improved version of DUDe to tackle several issues which we and many of you have discovered and reported. Unfortunately, many of these issues are more difficult to tackle than anticipated and will still take a while before we can release a new solid version of DUDe. One of the main issues is the fact that the software freezes after receiving noise for some time, meaning that DUDe needs to be restarted each time. Attached is a version of DUDe with a dirty fix which resets the PLL every minute. The penalty is that a 1 or 2 frames are lost each minute, so the performance is less than version 5.1. It is however much more convenient for automated ground stations (like our own) and therefore we decided to release this version.

Transponder

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 test series will be:

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.

(Editor’s note : Downlink 145.880 -145.920MHz, Uplink 435.530-435.570MHz, Telemetry on 145.870MHz and 145.930MHz and a high speed downlink on 2405.00MHz)

S-band Transmitter

There seems to be a problem on the S-band transmitter causing the current protection to kick in occasionally. Maybe this is due to charging or some other effect, as the board is not protected by The Onboard Computer leaves the transmitter off after several attempts as part of an internal safety mechanism. We can still turn on the S-band transmitter through telecommand, but this will only last for a few passes. Most cases the S-band transmitter will thus be off and it reporting that we have turned it might not be very effective since it might be off again by the time you read the message. If you are still interested to try and receive the beacon signal of the S-band, please check the regular telemetry in DUDe under ‘Status’à’Satellite Status’à ‘Subsystem Status STX’ to see if it is actually on.

J. (Jasper) Bouwmeester, MSc.

Delfi Nanosatellite Program Manager &

Researcher Small Satellite Technology

Chair of Space Systems Engineering

Delft University of Technology

University of Louisiana CAPE II Cubesat Designated LO-75

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cape-2OSCAR Number Administrator Bill Tynan, W3XO announced the University of Louisiana’s CAPE II cubesat has been designated as University of Louisiana OSCAR 75 or LO-75.

Bill wrote to AMSAT mentor Nick Pugh, K5QXJ, and the CAPE II cubesat team, “I have been able to determine CAPE II has met all of the
requirements for an OSCAR number. By the authority vested in me by the AMSAT-NA president, I hereby issue CAPE II the designation University of Louisiana OSCAR 75 or LO-75. I, and all of the amateur satellite community, wish LO-75 the best of success”.

CAPE II operates on 145.825 MHz with a CW beacon with the callsign W5UL, it also includes a digipeater, text to speech operation, a simplex repeater, email and tweet functions. The ground station software can be downloaded from http://www.ulcape.org

FunCube-1 was recently issued OSCAR designation as AO-73. CubeBug-2 was designated as LO-74.

AMSAT-NA will be at HamCation 2014!

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AMSAT-NA will be at the 2014 Orlando HamCation on Friday through Sunday, 7-9 February 2014. Stop by the AMSAT booth where John Papay, K8YSE will be demonstrating his two remote satellite stations.  Don’t miss the AMSAT Forum on Saturday, February 8th.  It will be moderated by Dave Jordan,  AA4KN and will be located in the Children’s Safety Village, Classroom I, 1:45 – 2:45 PM.  Speakers will include AMSAT-NA President Barry Baines, WD4ASW on AMSAT’s activities, Lou McFadin, W5DID on the new HamTV experiment on the International Space Station, and AMSAT-NA Vice President for Operations on AO-73 and other new amateur satellites.  Drew will also will be on hand both Saturday and Sunday conducting portable satellite contacts and fielding questions from the crowd.

FLASH: Drew and John will be operating as W100AW/4 for the portable demos from the HamCation!