Posts by dm4im


    please keep in mind, that C:\\ProgramFiles\VideoLAN\VLC means the vlc executable must be in the folder named VLC.

    In other words: C:\\ProgramFiles\VideoLAN\VLC is NOT the executable.

    Or even in other words: C:\\ProgramFiles\VideoLAN\VLC\vlc.exe is the complete path to the executable.

    Is that the case on your win10? Also, try to install vlc.exe in the path that is represented by the translation to italian language (if that is the set language) , maybe that helps.

    73, Martin

    Hello Armin,

    you can use this board, click! : SI5351

    There are examples in the net, saying to cut a trace and use output 2 as the input. I recommend not to do this. If you need 2 frequencies, the calculation program might advice you to use output 0 and 2, not output 0 and 1.

    Remove the 25MHz TCXO and feed 10MHz via a capacitor.

    Download the SiLabs Clock Builder Software . Cheat the clock builder software by telling it you are using the SI5351 with 8 outputs and reference input.

    You will need a clean power source and you might need low pass filters at the outputs. I tested it with 24 or 25 MHz output plus 116MHz for my transverter, it works.

    73, Martin

    Don't worry. My microwave knowledge was zero before i bumped into this.

    As a cap i use the plastic cap that came with the copper tube from the hardware store. There was one at either end to protect it from dents, so i tried one for the poty. With or without the cap, the signal difference is marginal. You can use any material that is not heating up when you cook it in a microwave oven.

    Or try the original lens for now and replace it later. It will work, just not optimal. You will only notice this on the wideband transponder where every fraction of a dB counts, but not on NB transponder.

    If you don't mind destroying the original lens, you may cut off the excess material just leaving the length of the OD long enough to sit on and seal the end of the tube . Cut off the tapering material but leave enough of the ID so it has enough grip . Maybe apply a little glue you can easily remove if you go for a different approach later.

    73, Martin


    I don't think the plate will interact with the poty other than prevent it from being in the correct distance. It will shade the downlink a bit more than the poty alone does. The copper tube is any length, as long as it is not a multiple of a quarter wave @10.4GHz, but you'll want it as short as mechanically useful. So go ahead , make a long tube and put everything in place. When you found the best distance for the poty , You can cut off the excess length. With a dish that size you will have no problem other than finding the satellite :-)

    A different approach is to use the steel plate as the reflector for a helix. You migt even keep the original annular rings. They are there for a reason.

    73, Martin

    Jesus Christ!!

    I spent days positioning my dish properly , and now THAT?

    Back in the days, I was watching TV when Telekom shot Kopernikus out of Orbit. All of a sudden signals gone and zzzzzzzzzzzzzzzzzzzzz! Was an almost impossible task to realign everything.

    Jesus Christ!!

    73, Martin ;-)


    from what i see on your pictures and learned from your post, i think you can remove the original feedhorn and make a clamp or something for the poty to put it in front of the disc that held the original feed. Next you might buy a cheap lnb, cut off the horn and push it in the tube of the poty. That is what i did, my poty is homemade with copper tube from the hardware store. After some work with sandpaper, it fits nicely. You may want to maximize SNR . To do this, replace the 3 bolts in the disc with longer ones and extra nuts. This way you can move the disc together with the poty futher out. In your dish, the poty will sit about 5-10mm closer to the dish than the original feed, you need to compensate for that until you have max. SNR. You now should be pretty close to best position for the TX part of the poty, too. 1.8m is a killer anyway, i have 1.5m.

    LNBs - at least here in DL - are as cheap as 5€ . So if you destroy one , it's not the end of the world. Known working LNBs i use , are:….html?&trstct=pos_0&nbc=1…tml?&trstct=vrt_pdn&nbc=1

    Now that you no longer are in the EU, you may find similar offers from a local. I feed the lnbs with 25Mhz over coax. The single lnb via one coax where i inject the reference, the quad lnb over one of the four f-sockets. With four way lnb you can use both transponders same time.




    the program can run on two different computers and communicate via network , but the installation is the same on both computers. So if DJ0ABR is willing to split the installation into 2 parts, GUI and modem, the gui could install on a win pc without the drivers side by side with the flex software while the modem part could run on a raspberry pi or on a another windows pc. This may also eliminate the hassle with the virtual audio cables.

    73, Martin

    I like contesting a lot. Having said this:

    No antenna to rotate, no propagation to observe, predictable footprint of the signal. Whats the point? It's a repeater, just not fm and not on the ground. Contest is useless there. Maybe that's why it is called "challenge".

    Hi there,

    got it to work on a Xubuntu from 2020 in a virtual machine on my older Linux. It won't compile on the older Linux, because LIBGC is too old. Anyway, just sent some pictures and received them myself.

    Setup: TX: Elecraft K3 in DataMode, 70cm-Transverter, LZ5HP-Transverter.

    RX: Amsat Downconverter -vy old Model- , 2m-Transverter, Kenwood TS-850, USB-Soundcard. Of course this will not be the ultimate setup. Will try to use it on a Raspi4 . With this setup, 6000 8APSK is possible. To me it was important to see how my TX will work in the first place. Now that i know i can transmit, i will refine RX. CU


    a few more thoughts: Your problem will disappear as soon as you hook up your control box to a computer running satellite prediction software and let the program do the job. I'm pretty sure you will do that , because it's a fast paced job to control azimuth, elevation, tx-frequency and rx-frequency by hand while noting your qso-partners callsign, locator, name and report. This is especially true for the ssb satellites and even more when you do cw. Not so much for the fm transponders.

    Let's say , a satellite's AOS (Acquisition of signal - or is it arrival of signal?) is at 300° azimuth, LOS (loss of signal) will be at 120° azimuth. That would be an overhead pass. Your satellite prediction software will rotate to 300° azimuth and to 0° elevation. By the time the satellite rises above horizon, the software will rise your antenna in small steps to the calculated elevation up to 90°. Once reached , it will rotate azimuth by 180° and begin to lower elevation when the rotator has reached 120° azimuth. Never will elevation be greater than 90° (which isn't possible anyway, because when you go beyond 90°, you decrease elevation, not increase it)

    73, Martin


    so what you are trying to say, is, your meter shows the exact elevation of your system, but the rotator elevation physically goes below 'horizon' when the meter has reached 180° and you still push the button? Meaning elevation is less than zero (or more than 180) when you drove your rotator from 0° to 180° and a bit beyond? If that is the case, the mechanical range of your rotator simply is a bit larger than 180° .

    The only rare occasion to elevate the antenna further than 90° is when the satellite passes EXACTLY overhead, meaning you point your antenna to the azimuth where the satellite will show up over the horizon, then rotate elevation ALONE until it disappears below horizon again. All other passes are less than 90°, meaning you elevate your antenna while you also change azimuth. The elevation will never be more than 90° (= straight up) . I think no satellite calculation program will ever calculate an elevation greater than 90°. The meter of the control box to me is stupid. It shows a half circle of 180° on an instrument with 135° (?) range. The same is true for the azimuth, where it shows a 360° full circle on a 135° instrument. But that is another story.

    73, Martin

    Well , the position is indicated by a voltmeter with a scale showing degrees azimuth. It is the operators task to set the minimum voltage to be shown as 0 degrees and the maximum voltage as 360° (180°) . Everything in between might be correct or far off. It depends on the accuracy of the potentiometer , driven by the motor and changing the voltage for the scale. The same is true for the elevation.

    You can do this: Remove the scale from your rotator and make your own. Set the rotator to 0, mark it on the scale. Set the rotator to 45°, mark it on the scale. The more measurements and marks you have, the more accurate is your scale. But again, the 3 dB angle of your antenna seems to be so wide, a few degrees offset won't be noticeable in your receiver.

    Another reason may be a slip in the gear or the potentiomenter.

    73, Martin

    Ok, here my last idea.

    Verify there is power for the GPS-Antenna wether gps antenna is attached or not, just to be sure power is always there.

    Fire up V3D , leave it for 20 minutes. Get a cup of coffee. If it still won't finish the setup routine, remove power, remove gps-module, fire up V3D.

    In either case, determine the frequency @ WB-IN as exact as you can. Now, 10489.750-(390*<your measured frequency>) = <something near or far off 739MHz> .

    Set Pluto to <something near or far off 739>. See Signals?

    73, Martin

    Well, now it's <f-word> up, so it seems.

    I'm running out of ideas. Maybe it's time to bite the bullet and return it to amsat.

    I hope someone from the amsat team chimes in to provide further advice. Anyone?