Proposal for a telemetry test over NB transponder - narrow digital mode - very few short transmissions

  • Hi All

    Endless fun with the new toy. Thanks again to Qatar and Amsat-DL for this wonderful opportunity to deal with a really professional satellite stuff

    I would like to discuss an idea we are fine tuning to become a real project soon. We would like to deploy an small autonomous buoy in the ocean and receive it´s position and telemetry. This has been done before in HF using WSPR and JT-9 by ZL1SIX ocean floater. But due to the awesome performance of the NB transponder we are thinking about using it for sending telemetry

    We just need a few transmissions a day. And probably using a frequency jump schedule in order to avoid transmitting when the frequency is in use. We will not need a frequency to be left clear and used only for this purpose. No need to do so

    We already have the bouy case and it can hold small solar panels, as the top cover is transparent. There is a pole holding the strobe light which we can use to install a quadrifiliar helix which would provide a nice circular polarization in a half spheric pattern to the sat

    The digital mode to be used is still under discussion. As the communication channel is so good and the transmission rate so low (once an hour probably) it may be better to use something which can handle all the telemetry data in a short time, rather than using low data modes for weak signals which are really designed for HF. But it must be a mode many other hams can run, so to get the chance to receive and decode the telemetry theirselves

    So. What do you think ? Any comments are wellcome

    73 de Luis


    PS: Forgot to mention that there is an opportunity to deploy the buoy in the Indian Ocean. The satellite is at high elevation in the area

  • EA5DOM Hi Luis.. nice idea.. I think before starting the detailed discussion here you should try a prove of principal e.g. in a garden pool with waves and send the signal on a experimental base to QO-100. I think the type of antenna in the waves and the overall power consuption should be proved first. When this is proven there will be a solution for that.:thumbup:

  • Luis, despite being GPS locked I had unsatisfactory experiences with JT9 on QO-100, so perhaps another mode?

    And, I followed and received ZL1SIX buoy here and even helped Bob with time warping his JT9 transmissions .. so .. I am in !