LA1K / LA100K / LA1UKA

Installing an SPX-02 rotor on the LA1NGS SatNOGS station

SatNOGS is one of the projects we have been following with excitement for some time now. With SatNOGS, users contribute to create a freely accessible open source global satellite network. This is a great alternative to the traditional satellite service networks, which are expensive and hard to access.

A pass of ISS as recorded by the SatNOGS station LA1NGS at 15:51 07.12.2018

There is a SatNOGS station in Trondheim, LA1NGS, which is operated by NTNU Small Satellite Lab and Orbit NTNU. We have eagerly followed and used its recordings for various things, such as listening to QSOs on amateur radio satellites and viewing NOAA weather satellite images.

This fall we noticed that their rotor had stalled, so we reached out to them to ask if we could assist with solving the problem. After some discussion, we agreed on helping them replace a Yaesu G-5500 rotor with a new model, namely the SPID SPX-02 . There were some concerns with wear on the older model, as it had been in operation for quite some time, so a full replacement was desirable to ensure a long lifetime for the station.

The SPX-02 rotor after unboxing.

To install the rotor, we had to lower the mast and remove some coaxial cables from the service box that contains LNAs and phasing harnesses.

Full parallelization was achieved by simultaneously assembling the rotor controller for installation into the ground station rack.

The last step before mounting the new rotor was running new control cables, and soldering/assembling the connectors.

Finally we attached the rotor to the mast and gave it a spin.

We were lucky enough to be given the old Yaesu rotor as spoils of war. The plan is to repair the rotor, and use it to build a SatNOGS station of our own. Another blogpost is probably due on this if we get the rotor working.

As for the newly installed SPX-02, it operated smoothly for about a week of continuous operation. After that, however, there has been a number of hiccups. The MD-01 controller complains about time-outs on the sense lines after some time in operation. The jury is out on whether this is a hardware or software issue, but either way it is something that should be resolved. We feel a bit bad about leaving the system in a broken state after “fixing” it, hopefully we will get to the bottom of this soon.


  1. Stefan Wagener, VE4SW

    Has there been any updates on the use of the SPX-02 and the problems? Please let me know. Thanks!

  2. LA3WUA

    Hi Stefan, thanks for reaching out.

    We have not been able to check out the issue any further as we do not have access to the site (belongs to another club). However, we have heard about a third club struggling with similar issues with a MD-01 rotor setup. The working theory is that the cable we used is too small, which leads to problems.

    If we get around to checking out the issue in detail we will update with a blogpost on the matter.

    73 Øyvind/LA3WUA

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