AMSAT LNB with out 24MHz reference input will it work ?

  • Dear All ,


    Due to some unfortunate issues / situations I was not able to get he downconverter / reference board ( ordered it from amsat shop)

    and now I want to operate the QO-100 with the "DJ7GP V2 2.4 Ghz & 10 GHz antenna with LNB modified 24 Mhz AMSAT DL" I got from a secondary source.

    The question is is the LNB gutted completely ? or there is still a TSXO or PLL or crystal or something still inside of it ? so I can kind of work somewhat with the LNB in question ?

    Or if I power it up without a reference I will break it completely ?

    because I really want to operate this SAT but these issues with supply all of the the world make the situation difficult.

    Thank you in advance

    73 DE 5B4AKV

  • Hi,

    i'm pretty sure the lnb WILL NOT WORK without 25 or 24MHz reference. If you can't wait, try any ordinary modern unmodified lnb. It will drift a lot and will not be accurate, but you can work the satellite. Most modern lnbs have a crystal built in and are fairly stable, but not perfect.

    73, Martin

  • Hi,

    i'm pretty sure the lnb WILL NOT WORK without 25 or 24MHz reference. If you can't wait, try any ordinary modern unmodified lnb. It will drift a lot and will not be accurate, but you can work the satellite. Most modern lnbs have a crystal built in and are fairly stable, but not perfect.

    73, Martin

    That was what I was afraid my self. ( I was 99% sure this was the case)

    But Now next question I have a bullseye LNB ,

    how can I use the TX antenna of the moded LNB to get the transmission out ? because Its the only one I have TX capabilities ,
    together with the Bullseye LNB I can mount the one on top of the other ? I don't have a second dish to point to the SAT so that I can mount both LNBs on different dishes.

    In general this is a bad situation I got my self into.

    the next opportunity I have is in like 4 months.

    ;(

    Thanks for everything


    73 DE 5B4AKV

  • Hi,

    well, you can remove the lnb from the DJ7GP antenna and replace it with your bullseye lnb. To do this, remove the plastic enclosure from the bullseye lnb and cut/saw off the feedhorn.

    Make sure no chips fall into the lnb through the holes for the 2 antennas .

    If you have a dish for broadcast tv , you may want to use the bullseye lnb offset like this:

    My first attempts to receive the bird was with an unmodified lnb. I just drilled a hole in the plastic cap protecting the feed horn and stuck it onto the tube of the patch antenna.

    Like this:

  • Find an abandoned dish, any will do . 60cm is just right.

    The picture shows one of my first attempts with a dish i got from the junkyard. It even worked behind the colsed balcony door.

    If all this is not your cup of tea, you still can listen to QO-100 via WebSDR and only use the transmit capabilities of your DJ7GP antenna.

    In a later step, you add the receive capabilities once you got your downconverter.

    73, Martin

  • Err... from reading your posts again and again, i get the impression you think you need the lnb together with the downconverter to TRANSMIT . No.

    What upconverter and what TX do you have?

    Sorry for asking....

    I do not need an up converter because I have Adalm Pluto. ( I have a pre-amp and an amplifier to get the 2.4Ghz out )
    Down converter I also do not need because Adalm Pluto can RX the Mixed output from the LNB at 739 MHZ aprox.

    So what I will eventually do is what you I think said to RX my self from the webSDR and TX from local and see how it goes.

    Or I can take my other big parabolic dish to RX the SAT but I have no idea how to change the LNB on that.

    I will try soon :D I will keep you posted thank you for everything guys :D

    Update . :

    My time run out at my QTH and it was time to go. at least I managed a snaky night to align the dish with the sat while I had some time.

    so I got an update also from AMSAT that the package its on it what with the reference board and the new LNB

    on the next visit I will panel mount everything seal it and set it to work via Ethernet. It will be an interesting project :D

    Slowly slowly.

    Thank you for everything.