Posts by dm4im

    Absolutely right. Unfortunately the manaul does not refer to what this pot does, thus many owners never touch it.

    Correct me if i'm wrong: I think it sets the level of input power that is passed to the 4 resistors next to it. These convert excess input into heat. So while it may be true that 6 Watts is the absolute maximum, it is not necessary to waste power. It will only heat up the converter. The manual says the VOX circuit will trigger from about 100mW, so i believe anything between 200mW (to safely trigger VOX) and 1W of drive should be more than enough.

    The output is 200mW max. , so you need a big dish (>150cm dia. for a decent signal) or an amp.

    The DX-Patrol amp's drive is rated 70-80mW for full output, so you will not get around fumbling with that pot.

    73, Martin

    Edit: i believe anything between 100mW and 200mW of drive should be just fine.

    do you control output power by reducing the input IF power...?

    Yes. Many people use way too much input power. This is immediately visible as spurs on the transponder, so an attenuator 3-20dB or 10-40m lossy coax depending on how low an output you can set your transmitter help a lot. 200mW output equals 23dBm. You will need a big dish or an amp.

    73, Martin


    i tried this too, no joy.

    Obviously the software checks for availability of the USB-connections upon start . If only for example TS1 is connected and marked as MASTER in minitiouneConfig.ini , the program will run without problems. With the program running, when you edit minitiouneConfig.ini , set TS2 as MASTER and start a second instance, the new instance will again check for availability of the usb connections , find TS1 occupied and quits.

    73, Martin

    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


    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:

    Hi Fazlay,

    5. Improving stability - making a GPSDO with OCXO

    Here is a link how to do it. It is in german, but i'm sure there are projects in english language to be found.

    Simple GPSDO by DL4ZAO and DL7UKM

    A gps receiver provides a precise 1kHz/10kHz/ or 100kHz clock . The 10MHz from the ocxo is divided by factor 10000/1000/ or 100 to one of these frequencies . A comparator circuit provides a control voltage for the ocxo to adjust it's frequency.. When clock and divided frequency match, the control voltage is right and the OCXO is spot on frequency.

    The Arduino is there to tell the gps-receiver what clock is needed and takes care of the display (time, locator, whatever).

    6. Making a 25MHz clock from the GPSDO/OCXO using si5351 and a bandpass filter.

    Done that. It works.

    73, Martin


    you might consider feeding the 25MHz over the coax to the lnb, preferably from your shack. A tcxo built in the lnb will drift with temperature changes. Thus it is smart to have the tcxo in a place with minor temp changes. Furthermore, this leaves room for later improvement, like making the tcxo adjustable or feeding an odd frequency derived from the tcxo.

    73, Martin


    It seems the OCXO provides a 5V output derived from 12V input. Make this Output adjustable with a multiturn potentiometer and feed the voltage to pin1 . This way you can control the frequency - or have some smart circuit like a gpsdo do it for you.

    Here is a circuit , not exactly your OCXO but you get the idea: Control Voltage

    Please note that the pinout pins 3 , 4, and 5 in my example is different.

    73, Martin

    Go to your raspberry via ssh , then just type all those commands or copy & paste them.

    The command to download the software is



    git clone

    you may need to put https:// before github


    cd QO<TAB> & Enter to change into the directory


    ./prepare_ubuntu or one of the other scripts

    The rest will work as shown on github. Please note that linux is case sensitive, thus


    IS NOT


    73, Martin

    I think you failed to cd to the path where the software is located. After you did wget or git clone to fetch the software you need to type "cd QO< hit TAB to complete the path>" & Enter, this will change the directory . Then ./prepare_ubuntu_<your_choice> will run . Maybe you must make it executable with "chmod +x prepare_ubuntu_pluto" . By the way: Kurt failed to clarify this in the chapter "INSTALLATION" on github. Give me a shout on 10489.660 , my parking frequency.

    Edit: All prepare_ubuntu_***** scripts are executable already.

    By the way, the first thing i ALWAYS do on any linux i use is install the MidnightCommander sudo apt-get install mc.

    This saves you a lot of headache if you are an old fart like me and have worked with the NortonCommander under DOS back in the days


    73, Martin


    please describe what you achieved so far. When you start a browser on your windows-computer and type in the address of your raspberry, like , what happens? Are there other programs occupying the rtl-stick or using port 80?

    73, Martin

    :) Very happy! It ran out of the box on a RasPad with the original Raspad OS. Just downloaded the software, built an ran it. Not even downloaded the OS recommended by BATC. Now learning to use it and how to install a remote.

    73, Martin

    a DC block between LNB and Pluto is required. As I know Pluto does not have an input capacitor.

    Click: Available with 2 or more outputs, DC only goes from OUT to IN, not reverse

    Useful for single port lnb if you don't want to rx WB and NB simultaneously. The Minitiouner provides 14/18V.

    I have a 4-port lnb, so i use this device as a 3-way splitter on lnb Port 1 for all NB receivers like 2m-Downconverter (including 14V supply to lnb), RTL-Stick and experimental receivers. No danger to fry one of them. Port 2 is WB, Port 3 is 25MHz clock, Port 4 is terminated with 75 Ohm. This way i can rx NB and WB same time. No need to worry if there is DC on the output or not.

    73, Martin

    Hi, now that the webserver / rtl-stick setup is running, i tried out the Ryde driver and MiniTiouner for the WB-Transponder.

    i have some issue with the screen on my raspberry. It seems, i receive the WB Transponder as i have audio, but the video seems so big, that only a grayish picture is visible. Where can i set the resolution?

    73, Martin

    Alright, fault..

    Found the SETUP Button on the Webserver in the upper right corner. It was not visible in the Browser window because the window was bigger than the screen. Now that i know it is there , i can configure everything to my needs.....

    73, Martin