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Eshailsat Tx and Rx ideas



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    Date:18/01/18 Time:15:59
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    UKHASnet
    Eshailsat Tx and Rx ideas

    With the approaching launch (currently Q3 2017) of Eshailsat and the new transponder i have been thinking a little about how to get equipment ready for both Narrowband and Wideband use.


    Rx:
    80cm Dish and Octagon Dual LNB (PLL type).
    One port Vertical for Narrow-band segment and the other Horizontal for the Wide-band segment.
    External reference for the LNB at 25.6MHz, this allows the IF to be 1200MHz, ideal for DVB Rx.
    Narrowband: Still need to convert for Rx unless using rtl-sdr or similar, Base Transceiver is going to be the Red-Pitaya running HPSDR software, IF at 50MHz probably.

    Tx:
    3M Dish, 30W Spectrian PA or more - see below
    Narrow-band: Red-Pitaya with HPSDR software at 50MHz up-converted to 2400MHz.
    Wideband: DATV-Express



    Based on the specification for the wideband uplink (8MHz DVB-S2 requires 100W into 2.4m dish) here are some approximate numbers to get you started, the bandwidth and dish sizes are in 3dB steps.
    Remember DVB-S2 is a couple of dB better than DVB-S!.
    To generate the power required you will need an amplifier capable of about four times that below to get a reasonablly clean Tx spectrum.

    Power vs Dish vs Bandwidth




    More info to follow as things progress...










    Last page added:07/01/18 10:15
    M0DTS.co.uk