• This is my portable setup, the only thing you don't see on the picture is the FT817 and dc supply.

    35cm with well tuned helix 5.25t and with 6W only, i have 3dB less sig in peaks then upper beacon some weeks ago,so before the wider bandwidth we have now on the transponder.

    It's working better then the patchfeed. I have made a comparison list with different antennes for uplink, i will post it here later.

    Hmm, looks file is to big, need to change size first.

  • Dear all,
    I am working on a TX part with the pluto and Pre-Amp and Wifi-Amp.
    I am not sure which antenna will be the best for a small dish.


    I will get a 45cm Offset dish from Technisat within the next days. (technisat 45 digidish).


    What will be the best solution:

    1. Helix or

    2. Poty


    - plan is also to have the RX solution in once (next step)

    - have no equipment for measurements on 2,4GHz

    - best will be a ready to use antenna TX/RX solution or at least a DIY without adjustments


    Any good hint?


    73, Oliver

  • Buy a NanoVNA V2 - thay are about €60. Then you will have the test equipment to set up a helix or POTY. Either will do, obviously I prefer the POTY. A 45cm dish is quite small, it would be better to get a larger one if you can. You may need a little more power than the typical WiFi amp can deliver.


    Mike

  • A dish size of 60cm-75cm is strongly recommended if you want to receive hassle free.

    A smaller dish would exceptionally for portable operation.

    But it is definetly not optimal and you may not hear weaker stations on the satellite with a smaller dish.


    Keep in mind: To be as loud as the beacon is not the goal, it is the maximum limit!


    There should always be a good balance between receive capability and transmit power.. the "alligator" phenomena..

    Peter Gülzow | DB2OS | AMSAT-DL member since 1983 | JO42VG

  • Thank you Mike and Peter for your comments.


    Buy a NanoVNA V2 - thay are about €60. Then you will have the test equipment to set up a helix or POTY. Either will do, obviously I prefer the POTY. A 45cm dish is quite small, it would be better to get a larger one if you can. You may need a little more power than the typical WiFi amp can deliver.


    Mike


    Mike, I am the 'proud' owner of an NanoVNA-F, just 2month old, but that is basically limited to 1,3GHZ. So the VNA 2 runs up to 3GHz, what a pity, outdated with Nano-F in only 2 month ;-) . The 45cm dish is also planned to be mobile, a SG PA is also ordered to ensure the right/better sufficient power level.


    Peter, for the home shack I will use a 60x90cm 'Gitterantenne' for WiFi, it was relative cheap with 45€ and require no VSWR adjustments. Unfortunately I have not reach the satellite with the current set-up (TX should work, antenna not sure). RX up until now just with web-sdr in UK. Thank you for the hint regarding 60-80cm dish for RX.


    73, Oliver

  • Achim DH2VA has graphically illustrated the relationship between the various dependencies and how the SNR behaves with the size of the dish or which factors dominate. The graphics are also part of our official QO-100 presentation.



    The blue curve shows that a small dish leads to considerable disadvantages, but the advantages above 1-1.5 meters are at some point only in the range below 1dB.

    Peter Gülzow | DB2OS | AMSAT-DL member since 1983 | JO42VG