Posts by dm4im

    Bekommt ihr beide die Fehlermeldung: "recvfrom error" wie bwi DG5EM im Terminal zu sehen?

    Probiert bitte die modifizierte Version von ZR6TG mit dem grösseren Empfangspuffer.


    modifizierte Version

    und berichtet dann.

    Laut ZR6TG müsst ihr nur seine Version 0.89 herunterladen, entpacken und die vorhandene oscardata.exe Version 0.87 durch seine ersetzen.

    73, Martin


    ich denke, du hast alles richtig gemacht. Es sind eben keine Bulletins vorhanden.

    Gerade kam Bulletin #9 rein, nach geduldigem Warten, siehe rechts unten:

    Und nach weiteren Minuten Bulletin #2 und #4 . Einfach mal laufen lassen, warten und die fett gedruckte #Zahl anklicken. Dort sollte ein Bulletin zu lesen sein.

    Nach einem Klick auf "Öffne RX Dateien" kannst du prüfen, ob Bulletins empfangen wurden. Der Dateiname ist immer "amsat-", danach eine laufende Nummer gefolgt von ".blt" , z.B. amsat-310.blt . Schaue von Zeit zu Zeit nach, ob welche mit ansteigender Nummerierung vorhanden sind. Die 10 neuesten sollten angezeigt werden.

    73, Martin


    Use LSB for the sstv uplink and switch to usb when talking. Now set your tx frequency to 2400,150MHz. Your sstv signal should appear in the digital part of the band, but your voice signal in the SSB part. 8)

    73, Martin


    And what if you want to do DATV?

    Take the cable with the 12V OFF and put the cable with the 18V????

    Yes, or you rotate the lnb 90° . Or you use a lnb with 2 Ports, one for 14V / SSB , the other one for 18V /DATV . Then, of course you will need 2 power splitters, 2 power supplies etc. But you know that already, don't you?

    73, Martin

    You should have taken the photo with the foil removed, for better recognisability. i have this or a similar splitter and there all 3 OUT ports are labeled "power pass", but power only goes to "IN" and never to one of the other "out" ports. If it is the same: There are 3 connectors labeled "out" . Connect your power source 14 or 18V to the one labeled "Power Pass" Check if there is voltage at the port for your lnb , labeled "IN" , but not at the remaining ports labeled "out". If all is good, connect your RX to one of the "out" ports and your 25MHz source to the other labeled "out".

    The Satellite Experimenters Handbook, 1984, says we are dealing with Faraday Rotation, where linearly polarized signals from a Mode A satellite (AO-7 IS a Mode A sat) slowly rotate when they pass through the ionosphere, most noticable on 29MHz as fading. The polarization now is elliptical. A circular polarized rx-antenna will compensate this, but will not cure all fading , since the the gain pattern of the antenna in the spacecraft constantly changes as it spins.

    So, i think it is best to switch from RHCP to LHCP and back while observing the signal.

    You may ask why do i care about this? Well, after all it is less an experiment for reception of a Mode A satellite, but more an experiment for diversity receive on 12 & 10m. I will focus on that and put proper reception of AO-7 very low on my to-do list.

    But if polarization was known beforehand, I sure had set it correct. Will i ever bother switching from RHCP to LHCP for AO-7, i don't know.

    Thanks for reading

    73, Martin

    Thomas, thanks for the reply, BUT

    i'm not asking if a dipole will do. I know it will, i've been using radio sputniks when they were operational.

    Now that i have this circular polarized antenna, i want to set the proper sense of rotation to benefit from the circular polarization it has by design. If i set the wrong rotation, losses will be higher than with a linear antenna. If i set the correct rotation, performance will be better than with a linear antenna. It's a matter of flipping coax shield and core. I just have to do it right once.

    73, Martin

    My 2 Cents on this:

    You are trying to create a workaround because your OTG USB Network device doesn't work as you want it to work.

    But this creates even bigger problems. Get your Network device working and you'll be fine.

    If you really want to deal with problems: You may need to route the audio output from your teamviewer to the audio input of sdr-console via virtual audio cables. I'm not sure if this will work. Good luck.

    73, Martin

    Dear Satellite enthusiasts,

    i recently read in cq/dl ham magazine about a circular polarized (CP), omni directional cross-dipole (aka turnstile) covering 12m and 10m and everything in between.

    Looking at the frequency range of 5 MHz, I was very sceptical. But with all the required hardware handy, i gave it a try. No tinkering at all, just built per the article, my antenna analyzer confirmed a good , flat match over the entire range from 24.9 to 29.7 Mhz with a perfect match somewhere around 26.7MHz. This is a contradiction to the statement in ROTHAMMEL antenna book, where turnstile antennas are described as narrow band antennas. Anyway, with the dimensions given in cq/dl, it is not narrow band at all.

    Polarization from sky wave signals (dx) never are pure V or H, but they sure are not CP. Hence the sense of rotation the antenna is constructed for is not important. There should be some advantage over a V or H linear polarised antenna and i can live with the loss i will have from pure H or V signals coming in via ground wave.

    But if i want to receive AO-7, what polarization should i set the antenna to? Is it RHCP or LHCP - just connect the delay line correctly, no big deal. Do i need to switch polarization? Spin modulation comes to mind. Found nothing meaningful (to me) in the ARRL satellite experimenters book, but honestly , i did not dig too deep.


    Now calculating the dimensions for the same antenna, but for 15m - 17m.

    73, Martin


    this happens when you close all receivers prior to shutting down SC (sdr console). If you shut it down with a receiver in USB mode still running, it will start with the last frequency, mode etc. when you hit the "Start" icon.

    IIRC you can set a checkmark "automatically run the last receiver when SC loads, no need to hit START" somewhere in the guts of SC. BUT if there was no last receiver when you shut down SC, it can't come up with one.

    So maybe you just need to loose the habit of stopping all receivers before leaving SC.

    Does that help?

    73, Martin

    EA2ARU Please more info. Is it Windows or Linux?

    The beauty of running this under Linux is: There is no virtual audio cable.

    See the picture , it is gqrx and hsmodem running on a ubuntu ( Lubuntu , that is). The audio device gqrx delivers audio to is the soundcard, the capture device for hsmodem is MONITOR output of the soundcard. 73, Martin

    EA2ARU There is no Trick. Connect the input of your soundcard to IC9700

    ACC1 , Pin 2 (GND) Pin 5 (Signal).

    OR to Speaker out (not recommended, but will work)

    OR to headphone out (not recommended, but will work)

    Goto hsmodem SETUP, set RX to your soundcard input. Tune your IC9700 RX-frequency until you see the constellation like in post #59 . Follow the instructions in post #59.

    Also, carefully read instructions in your manual about the speaker configuration in chapter [EXT-SP MAIN / EXT-SP SUB] if you connect to your speaker output.

    EDIT: Additionally, check the manual provided by Amsat (see next post) if you want to use USB SOUND features for RX and TX with ICOM Transceivers.

    73, Martin

    PA1EJO Set "exclusive mode" for your virtual audio cables first.

    Then always start hsmodem before you start sdr-console. That should do the trick. Works with VB-audio cable here (others say, vb-audio cable doesn't work at all, maybe this is the workaround ).

    Hi Ernst,

    Go to "SETUP", select the audio device carrying RX audio (VAC in your case).

    Bring the volume up to about the level shown in the picture below.

    Tune your rx to make the signal fill the "Tuning Window", with the leftmost peak centered in the "Ref" column. The circle should show a constellation like in the picture.

    Go to "File", wait for the button " Open received HTML file" to show up. Click on it and have your browser display incomming data.

    73, Martin