Posts by dj0abr

    Hi Martin,

    same gray picture here, yesterday the Beacon was sending just a gray or yellow picture. Should be ok today.

    This is a block diagram of the setup:

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

    The miniature TX transformer in one of my Plutos is broken. Does anybody know where to get a replacement?

    vy 73, Kurt, DJ0ABR

    with WIndows 11, Microsoft is trying to drive us into a very strange situation. My PC at home is to be converted into a high-security machine, with restricted access for normal users. Maybe I'm not the only one who's worried about it.

    Anyway, that was the motivation to switch the whole shack to Linux. For the DATV reception I used the Windows-Minitiouner software. This has now been switched to Ryde and Raspi 4.

    And that move was much easier than expected. The BATC Ryde Software works out of the box, absolutely no tricks or fiddling required. Very good job BATC!

    To make tuning as easy as possible, I have included a link to Ryde in the QO100 WebSDR. Now it is possible to tune by mouse click in spectrum or waterfall. Since the WebSDR runs via browser, a smartphone can now also be used to remotely control Ryde, which is very convenient.

    The WebSDR allows up to 20 simultaneous browsers, so can be used on multiple PCs or phones in the home network at the same time, all of them can be used to tune ryde.

    Ryde is available at github:

    and the modified QO100 WebSDR:

    The WebSDR runs on the same Raspberry-4 as Ryde is running (or on another if you prefer)

    This picture shows a DATV reception via ryde, the WebSDR in the top right of the screen. The picture was just received by DL3MX using ryde and QO100 WebSDR.

    vy 73

    Thanks a lot!

    Regarding CW, my CW is a bit rusty:-), so whats important for CW.

    RX: maybe a narrow (adjustable) filter.

    TX: sending a simple sine wave with i.e. 800Hz should do the job ? In this case it may be required to shift the TX frequency by this 800Hz, I'm not sure.

    On an SBC the GPIO can be used to connect a key, or two GPIOs for a paddle.

    Today I finished the integration on Odroid which was a bit tricky, but its done now.

    vy 73, Kurt

    Hallo zusammen,

    derzeit sind wir am Bau einer QO-100 Portabelstation. Raspi 4 mit Pluto via ETH.

    Am Raspi ist ein 7" Touch Screen angeschlossen, 1024x600 pixel, der Transceiver wurde für diese Auflösung erweitert.

    V1.66 wurde für Touch-Bedienung schon optimiert, ein paar kleinere Dinge möchte ich aber noch machen damit man mit dem Finger genauso feinfühlig bedienen kann wie mit der Maus. Vielleicht wird auch noch ein Drehgeber angeschlossen, es geht doch nichts über einen satten Aludrehknopf:-)

    Versorgt wird das ganze mit einem kleinen Bodnar-GPSDO mit 25 MHz und dieser Schaltung:

    LNB Power+Clock

    Vermutlich werden wir das System in 2 Gehäuse einbauen. Eines mit Pluto und PA, das direkt an der Schüssel montiert wird. Und per ETH angeschlossen das Gehäuse mit RPI und Display, das dann am Tisch steht. Mal sehen, was uns da noch alles einfällt.

    vy 73, Kurt

    wobei ein nach Amsat-DL modifizierter LNB zum Einsatz kommt, also wo die 24/25MHz Auskopplung eingebaut ist.

    The valid frequency range for the RFPLL phase detectors is 10 MHz to 80 MHz, and the scaled frequency of the reference clock must be within this range.

    das schreibt AD, leider stimmt das nicht. Ich habe das heute ausführlich getestet, da es auch einige Hinweise im Internet über Probleme gibt.

    Die PLL arbeitet erst ab 20 MHz (bis 80 MHz) stabil. Unter 20MHz hängt es vom Zufall oder der Temperatur ab ob es geht oder nicht.

    Ich habe derzeit 4 Plutos hier. Einer läuft mit 10 MHz, einer ab 15 MHz und die anderen beiden ab 18 MHz stabil.

    Bei 25 MHz sind aber alle einwandfrei. Es steht einer Speisung von Pluto und LNB aus der gleichen Quelle also nichts im Weg.

    Die Modifikation im LNB ist relativ einfach zu machen, entweder über ein eigenes Kabel oder auch über das Sat Kabel (wie mit dem Amsat Downconverter). Seitdem ein "netter" Zeitgenosse seinen Sägezahn über die Bake laufen lässt ist mir das lieber als der Bakensync.

    Der QO-100 LINUX SDR TRANSCEIVER versucht den Bakenlock auf 2 Baken zu beziehen um dem Sägezahn-Störer zu entgehen.

    Hallo Detlef,

    danke für den Hinweis, hab deinen Ausschnitt (im anderen Thread) aus dem Manual gelesen.

    Für optimalen Phase Noise. Bei 80MHz arbeitet die PLL scheinbar am besten.

    Für QO100 könnte man überlegen im Pluto mit 50 MHz zu arbeiten. Man muss irgendwie auf die 25MHz für den LNB kommen, das wäre dann mit einem 2er Teiler einfach zu machen.

    vy 73, Kurt

    Hallo zusammen,

    das Wiki zum externen Takt für Pluto Rev.C wurde auf den neuesten Stand gebracht.

    Ich habe die dort beschriebenen Einstellungen auch getestet und sie funktionieren gut:

    was mir sehr gefällt ist, den Pluto mit den gleichen 25MHz zu versorgen wie den LNB. Für die Portabelstation reicht dann ein Bodnar GPS was den Aufwand reduziert. Wenn man den Takt auf mehrere Leitungen verteilt braucht man normalerweise 100 Ohm Serienwiderstände da es sonst Überschwinger gibt die den Pluto stören können.

    vy 73, Kurt

    Hi sTef,

    the minimum requirement is to have a stable clock.
    This is most important inside the Pluto. While it is possible to do reception with the standard clock

    it is impossible to do any transmission, the drift is faster than other people can follow your signal using a RIT.

    If you have a Pluto Rev.C then it is very easy to install a connector for an external clock, just needs an adapter cable.

    If you got a Rev.B Pluto then you need to do some very difficult soldering, but there are some people who could do this modification it for you (maybe here in the Amsat forum ?).

    I personally also prefer to have a stabilized LNB.

    The setup for our QO100 club station includes a pluto with a modified TCXO (no external clock, but the internal TCXO was repaced with a better one). And a Leo-Bodnar GPS which is used to stabilize the LNBs reference clock.

    There are also some documents describing a PTT for Pluto. This is fine, but currently I don't use it. The PA is always on, and during RX it draws only quiescent current, which is low enough.

    Regarding amplifiers: the TX output is about 0dBm. There are several options to get the required 5watts.

    One option is to use the Amsat-DL 46dB amplifier (…etrieb-mit-sdr-46db-gain/ ) if you can get one.
    Also the Amsat-DL Upconverter (…con6w-6-watt-upconverter/ ) is working fine if the input attenuator is removed.

    In our club station we are using the third option, which is a Analog-Devices CN0417 pre-amplifier (+20dB) which makes 100mW. After the pre-amp we use this easy to build amplifier ( ). The output is 5 watts. This 10W PA was built some 100 times and is working very well (Ernst, DL1EV, has empty PCBs, if you need one write an email to )

    The advantage of the Amsat-DL boards is the 12V power supply, while the 10W PA needs about 24 to 30 volts.

    73 de Kurt

    Hello QO100 friends,

    I have been working very hard on this QO-100 Transceiver project for the last couple of week.

    Now everything is ready and working. On large PC monitors and down to tiny 3,5" raspberry PI touch displays. Clicking the monitor symbol in the left top corner shows the screen resolution selection.

    The GUI is optimized for Touch Screens or Mouse. A keyboard is not required (except for the initial setup).

    The Pluto can be connected via USB or Ethernet.

    Now I am ready for your ideas, reports and requests.

    (Poll's question was solved in the github discussion.)

    So the first request from HB9EIY is for an external PTT board, I will order one and try to implement it.

    The latest version contains some languages I do not speak. I did the translation with google. So please check if french, spanish, portugees and italien are correct, Thanks. (please check the SETUP window, this is the only window which uses translations)

    vy 73, Kurt, DJ0ABR

    Hallo my frieds,

    yes, I am reading all these suggestions, and have already done some of them. I.e. the pilot tone suggested by DB8TF is implemented in the actual version 0.64.

    The pilot tone is a little peak at 100Hz. And the spectrum display has a red 100 Hz line for tuning.

    I am currently working to fix a very complex issue, I rewrite the Windows Audio Driver, which is quite complex to get it reliably working. Unfortunately all the free, open software for Windows Audio has many problems, so it was neccessary to fix that. This will take about one week, then I publish a new version.

    The question from here and from emails are answerded in a new FAQ on

    When the current work on the audio driver is finished, I will have more time to participate here in the forum.

    vy 73
    Kurt, DJ0ABR

    just got the measurements made by DC1RJJ on a professional analyser:

    the filter looks fine.

    I was very lucky that I calculated the corner frequency to be 3.5 GHz. A little less and it would be too low.

    vy 73
    Kurt, DJ0ABR

    I don't know this specific problem,

    but I2C problems when connecting external components (like displays) happen frequently.

    What I would try is to solder 3,3kOhm resistors between Vcc and SDA, and also Vcc and SCL, directly to the connector on the display.

    This makes the I2C lines a little faster, maybe it helps.

    vy 73, Kurt

    great piece of Software !

    when I connect the Pluto via Ethernet, it is found and displayed in the device list.

    If I connect i.e. the SDRplay via USB, the device is not found. The SDRplay works with SDRconsole on the same machine. Also if I connect the Pluto via USB it is not found.

    Are there any special settings in order to work with USB devices ?

    vy 73, Kurt

    it took almost one year, but now the filter is build and is already in use between PA and feed.

    the flansh N connectors are Telegaertner, I found them at UKW-Berichte with an M3 thread instead of a solder pin.

    This is the inner part:

    it was turned by Ernst, DL1EV, on a Lathe. He did a very good job, almost 0,02mm precision.

    The plastic spacers did not work well (wrong dielectric constant), so I repaced it with paper spacers which work fine.

    Since my equipment only works up to 3GHz, I will ask another OM for a measurement up to 10 GHz. But so far, the filter does its job.

    vy 73
    Kurt, DJ0ABR

    designed by:…mpedance_Lowpass_Coax.php

    implementing the wideband Spectrum was easier than expected:

    finished and working with Pluto and remote controlling the Minitiouner software.

    In the waterfall you can see if two people are transmitting on the same frequency, like in this picture on 10497,250 MHz.

    vy 73
    Kurt, DJ0ABR


    the new version V2.9 from July/24 2020 supports the Adalm-Pluto (and RTLsdr and SDRplay as usual). As usual it has auto-hardware detection, so no special setup required.

    I have added some information on how to build it for the pluto. It is as easy as for the other devices.

    It works if the pluto is connected via USB.

    USB-Ethernet connection is still under evaluation.

    The final goal for the Pluto is a WB Spectrum/Waterfall because the new band plan requires more bandwidth then the SDRplay can handle.

    For installation clone this github repository:

    and follow the instructions in the README.

    For people used to the older versions: do NOT make any modifications in the header files ! All required settings are now done in the browser by pressing the SETUP button (top right in the browser-window).

    If you have an older version installed, then make a new directory or delete the old version completely. This avoids mixing old and new files on your disk.

    vy 73
    Kurt, DJ0ABR

    Hi Joshua,

    I have look for replacements, but non of the possible transistors are available, or extremely expensive. It looks like there is a shortage in production maybe due to Corona.

    The 30W option was originally developed for small camping dishes, like the dish we are using for our portable club station. If you are using a normal >=80cm dish, then the 10W amp is a good choice. It gives real 8W which is enough the trigger Leila.

    vy 73, Kurt, DJ0ABR

    during my work on the 3-helix-feed I made a lot of measurements to compare it to other feeds, including the POTY.

    I have build many Potys until now (for DH5RAE, DO1RX, DG6RCH, DG6FAX, DL3MX, DL1EV and myself), all worked OK, but had some drop in TX performance compared with a simple helix antenna. Something between -2 to -3dB compared with a helix (when monitoring my own signal via QO-100 in a spectrum monitor).

    Also I talked to many people on QO-100 who had similar experiences, mainly because it was very hard to tune the "two" virtual antennas to the correct frequencies and to see the two resonances in a VNA. This results in a poor circular (or even no circular) polarisation which explains the -2 to -3 dB drop.

    I have read the manual (written by G0MJW, PA3FYM, M0EYT) hundred times, but this week I focused on this remark on page-4 about the distance between the to copper plates:

    "Aim for 3.0mm, not about 3mm”.

    When building a POTY I use 3mm aluminium spacers while soldering the copper plates. But this always resulted in a distance of the finished (and cooled down) antenne of 3.1 to 3.2mm.

    This week I did it different. I sanded my 3mm spacers to exactly 2.9mm and used it to build the Poty. The distance was now exactly 3.0mm.

    What a difference !!!

    When connecting the antenna to my VNA, it was almost perfect without any adjustment. The two dips are almost exactly as shown on page 7 "modelled return loss". It tooks only a few minutes to squeeze the copper plates to a perfect match.

    Also I found that the way how the connector is mounted on the reflector has hugh influence on the tuning of the Poty. I do not use screws any more, instead I solder the connector directly to the reflector. Also the hole for the central wire must be small. If its too big, the few mm² of missing copper will disturb tuning.

    Today I mounted it to my Gilbertini offset dish (f/D 0.67) and the signal was almost identical to the 4-turn helix.

    I also did a few RX tests with different dielectric lenses because I found STL files on But none of these lenses worked for me. The only lense working perfectly is the cap of the Red Eagle Black Buster.

    Thanks to G0MJW, PA3FYM, M0EYT for this excellent POTY!