Posts by dm4im

  • Down Converter V3d defect?

    Alright, it seems you are not a ham-radio operator, otherwise you'd knew what a handheld or walkie talkie is.

    So you can not transmit on 437MHz to check the lnb.

    Ok, 40ish MHz an 25ish MHz is good! Means the TCXO in V3D is working and you have output, just not disciplined by GPS.

    Now, who modified the LNB? Was it someone who can check it ?


    Feeding the UNMODIFIED lnb with 24(25) MHz external will not work. It will use it's internal crystal.

    But you should see signals on 144MHz IF YOU jumper V3D to 25MHz and listen on 144MHz. The output of the unmod lnb is 739 MHz and will be converted to 144MHz if V3D is set to 25MHz , otherwise , when it is set for 24MHz it expects 1129MHz to convert it to 144MHz, so if you still feed in 739MHz, the output WILL NOT BE 144MHz. Here's why: Modern lnb's use a 25MHz crystal, multiply the frequency by 390 to get 9750MHz . 10490MHz-9750=740MHz . In order to receive the Amateur TV-Transponder with consumer electronics satellite receivers, which cannot receive 740MHz, one must use a frequency they can handle. So if you feed 24MHz instead of 25, the result is 10490-9360 = 1130MHz, which they can handle. So i think you are close to receiving with your unmodified lnb->V3D->Pluto on 144MHz if you set V3D to 25MHz. Try it. Just don't bridge NB IN and WB out, but hook the unmod lnb to NB IN. If that works, the culprit might be the modified lnb. So once you have a working modified lnb, next step is to find out why gps doesn't work.

  • Down Converter V3d defect?

    GPS Antenna: Any that can handle the voltage from V3D should do, there are many available ranging from just below 3 V to just above 5V.

    Modified lnb: Is it known to work properly (like give it to someone to test in a different setup) , do you have access to a 24(25)MHz source? Do you have a frequency counter or shortwave receiver to verify 10MHz at the 10MHz output, 40MHz respectively and 24MHz at the WB-connector of V3D (careful, there is 18V , pull the jumper before that). Do not measure at the gps-module, measure at the dedicated outputs. IIRC you can use V3D witht the gps removed , you then should also find those frequencies, just maybe a little offset. I'm still convinced that you loose the gps-satellites. BTW, it takes a couple of minutes for V3D to provide all outputs after it was powered up and has gps signals.

    Can you transmit with a handheld on 437.075MHz in front of the lnb to see the 24th harmonic on 10490,400?

    How did you receive 739 MHz on gqrx? What was the setup? Was it different from the setup when you received on 144MHz? Just the lnb or did you exchange more components? Is there a short in the plastic bnc output->144MHz? When you use the unmodified lnb instead of the modified one, does the combo lnb -> V3D -> sdr(pluto?? or what?) ->gqrx work?

  • Down Converter V3d defect?

    Quote from SWL-Jonas

    So if the display says "Syslock : wait" the GPS connection is lost?

    I think so. Did you reposition your GPS antenna? Where is your antenna located? Indoors? Can you try a different GPS antenna? At my qth, if i put the antenna behind the window and shutter, gps-reception now and then drops to zero. If i put the antenna outside just on the other side of the window and shutter i have 7 satellites minimum.

    Quote from SWL-Jonas

    In my version of the Down Converter this signal has to be provided by an external source, right?

    Yes. I'm not sure about the level. Remove the GPS Module , put a jumper across 3 & 4, feed 10MHz to 5. The frequency schould be extremely accurate, because it will be multiplied to provide 24 (25) MHz and the LNB will multiply it factor 390 for 9360 (9750) MHz, so even a small deviation will result in an offset. BTW, your LNB multiplies by 390, right? If the multiplier is different, we need to recalculate.

    Please name the brand and model of your lnb.

    Quote from SWL-Jonas

    And for the GPS module: Could I power the module with 3.3 V and measure the frequency output at pin 4?

    You might, but what for? You can check for 10MHz while it is built in, no need to pull it out.

    You said you successfully use an unmodified lnb. So the dish is pointing to the sat. One error eliminated. But: How do you feed the reference from V3D to your modified lnb? The reference is on the wideband connector only, not on the NB-Connector. So if your lnb shares output and reference input on a single connector, you need to rethink the setup.

  • SAT Controller SDR Nano

    Hi,

    in Post #200 , your converter is a silicon labs 2102, in post #206 it's a prolific. Are you sure you have checked the prolific with sdr-console or did you only verify that the silicon labs is working? Try the silicon labs under linux as well as the prolific under windows just to be sure.

  • SAT Controller SDR Nano

    Well,

    you can check if raspberry recognizes the the cable by typing "lsusb | grep prolific" in a terminal. Your photo from an earlier post shows raspi can handle the cable. See entry "prolific 2303 on ttyUSB0" or so. Windows has driver problems with the prolific converters because of chinese fake chips and drivers refuse to work if the chip is fake, but linux doesn't care about that, it will work out of the box. So, no, your cable is not the culprit as far as the connection raspberry<>converter goes. Do you have an oscilloscope to check the other end of the converter that plugs into the yaesu? Are there signals detectable?


    EDIT: You said, it works with sdr-console, so the hardware should be fine .

    In a terminal, you can type "groups" to see if the user pi has permission to use tty , but if Frank put that wrong, this forum would be swamped with complaints.

    You may want to install a serial ports emulator on your raspi, set it to /dev/ttyUSB0 and baud rate 4800 to see if your radio talks to it.

    Feel free to ask for further help if that all is beyond your knowledge.

    All that given you are in a hurry and want to get to the bottom of things. Otherwise , wait for the advices Frank will give you for sure.

    73, Martin

  • SAT Controller SDR Nano

    Hi,

    will it work if you tune the raspberry or the yaesu to the transponder frequency range (.489.500 - 490.000) ? Your photo shows both outside while uplink and downlink qrg do match. Maybe Frank inhibits TX if frequency is out of range? 73, Martin

  • Down Converter V3d defect?

    Hi,

    Reposition your antenna. According to Fig 8. , check if the gps-module is aligned with the pins and that there are no solder bridges shorting Pin 3 and 4. Can you verify the voltage on Pin 1? If everything is good but V3D still won't load further than to the point where it's stuck now, , i think it's time to ask amsat-dl for advice what to check. As a last resort you might return V3D to amsat for repair.

  • Suitable preamp for a HT

    Hi,

    you said "for now". Unless the cable you are using is very long and/or thin and thus lossy, I think you will not need a preamp for the FM-satellites at all, given your transmit power is about 5W from your hanheld? So for now go without a preamp. Or buy a preamp AND an amp. Being able to hear even the weakest signals makes no sense if you don't have enough power to be heard. And vice versa.

    But in the first place, you will need a transceiver capable of transmit on one band and receive on another, simultaneously. The FT60 can't do that, can it? Or you need a second transceiver for the other band.


    73, Martin

  • Down Converter V3d defect?

    Hi,

    i sold my V3D some time ago, so I can't duplicate your tests. In any case, the LNB - connected or not - does not affect the reading / display. IIRC "Sysclock wait" implies V3D is not fully up yet. Maybe you have trouble with the satellites. Reposition your GPS-Antenna might help? You do have a gps-antenna, do you?

    ****EDIT*****

    I think i know whats going on!! Your display shows V3D is set to external 10MHz Reference Input! Remove Jumper on Pin 3 and 4. OTOH, how can you install a gps-rx AND the jumper? hm...


    Your screen should look like this:

  • Down Converter V3d defect?

    Hi,

    I had erratic and unexpected readings on my counter just as you had.

    Get a Display like this: https://www.az-delivery.de/col…/1-3zoll-i2c-oled-display ,

    hook it to your Downconverter via a 4-wire connection. Amongst other Info, it will show how many satellites you receive, so you can tell THAT is or is not the cause for the trouble. I used the V3D for a while and noticed (in my qth) gps-reception is weak or completely fails now and then. I would never know if the unit was in a box where you can't watch the LEDs. OTOH a box is important because every small airflow causes the TCXO to drift and makes the correction do it's job. You can see that as drift on the downlink.


    73s , Martin

  • Does Anybody has soluce to run both raspi gqrx and gpsdo (Bodnar) ?

    Well, Eric,

    I suppose the Leo Bodnar Mini Precision GPS Reference runs on USB-power, either from a Computer or a USB-Charger. The larger one has a DC socket. Look at the pictures :

    http://www.leobodnar.com/shop/…cPath=107&products_id=301

    "Additional Images"

    For the larger one ( not Mini ) the site states: "It does not need any drivers installed or even USB connection. You can use external 12V power supply without USB attached."

    There you have it. Once you have a stable 10MHz clock, you may also derive the 25MHz for your LNB from it.

    Take a look here: https://wp.project-launch.net/

    It shows what you can do if you want to build it yourself. F1CJN took it a bit further by using a OCXO instead of a TCXO, DL4ZAO and DL7UKM made a nice PCB with features like Measurement of Control-Voltage, I did some cosmetics and incorporated a temperature sensor and a bit of code to handle a Si5351 for 25MHz output and some features for the display - like show time with leading zeros etc -that initially weren't there.

    There will be a virtual lecture on the "UKW-TAGUNG" in Weinheim, which will take place online. Find info here:


    https://ukw-tagung.org/vortraege/


    There is a Translator-applet in the upper right corner.

    73, Martin


  • Does Anybody has soluce to run both raspi gqrx and gpsdo (Bodnar) ?

    Hi,

    please specify your query. What are you trying to do?

    If you just intend to use gqrx / sdr-stick, go ahead and do so, there is no problem with that.

    My recommendation for a well working setup (besides DL3DCW's satcontroler) is to hook a raspberry (or any other linux computer) equiped with a rtl-stick into your local network, install rtl-tcp on it, set and forget it.

    Then use your favorite software on a different computer.

    My setup here is a small shuttle pc running as a server for various tasks like mesh-network, recorder for surveillance cameras, cloudserver, pi-hole dns-server etc. And rtl-tcp. It's running 24/7 anyway. I access the stick via network with gqrx or sdr-console, what ever comes to my mind.

    Edit:

    I just read the manual for a Leo Bodnar GPSDO . You hook up the USB-connection for programming it only , then it runs stand-alone. Is that what you refer to and probably didn't quite get?


    73, Martin

  • SAT Controller SDR Nano

    Hi,

    maybe it will run if you just extract the missing and incompatible files from a new image , then copy them to your /boot folder.

    I just learned that there is a new firmware available allowing the pi4 to boot from usb. Maybe your pi4 has a new firmware and wants to boot from usb, but DL3DCW's image isn't ready for that. See https://www.tomshardware.com/how-to/boot-raspberry-pi-4-usb


    Chapter8 mentions to copy .dat and .elf files to the boot media.

  • SAT Controller SDR Nano

    Hi, there are no parameters possible via command line. You can start GQRX via script, but you can't hand over any commands to GQRX.

    If your intention is to have a easy-to-access satellite downlink, you might want to check out DJ0ABR's websdr. It provides a browser accessible gui.