Posts by DL4OCH

    Gentlemen,
    with all respect, we have less bandwidth than stations in die WB-transponder for DATV. If we are starting to do pure data-services, where is the bandwidth for TV? What are the next plans to overcrowd that transponder?

    Right now, there is already a standard for IP over DVB-S2.
    But on the the other hand, we have done data over TV even in the analogue days. Did somebody remember Videotext? In DVB we are just talking about PIDs. If either we are doing SCTP, or MCTP, both are multiplexes.

    Right now, even if we transmit a "simple" TV-channel, we are already talking about PMT,PAT, Video PID and Audio PID. Did anybody recognize, that the program-name is our callsign? In fact, we are sending a simple EPG as well.

    If there is the need for a "data-channel", just decrease the symbol-rate for video in the beacon and use f.e. 500kSym/s of that stream to multiplex IP-over-DVB-S2 into an new PID.

    What are we loosing, when implementing data-services as a new PID into the beacon? Nothing, except a loop-video, we've seen for the past month with full bandwidth.

    Just my 2 cents.

    Looking forward to have a DATV-QSO with you. 35cms and legal limit in Germany. That's a challenge.
    I can decode up to -4dB to the beacon, so you might have a chance.

    I'm ready with the same level you can transmit with 1 MSym/s. It's just a question of removing the "insect-savers" from the exhaust-pipes for the fans.

    Heiner,
    not with a FEC of 2/3, maybe 1/4. And you will struggle to receive your own signal with that size. Even the beacon is almost impossible to receive with that dish-size.

    And finally, with a FEC 1/4 your video is limited to thumbnail-size.

    125 KSym/s or less will work. For thumbnails

    I really recommend a bigger dish than 60cms. With 60cm you really need much power to get a DATV-signal readable, even for you.

    You should try to get a dish with at least 1m, better 1,2m. With that dish-size, you'll be able to transmit with 250- 333 kSym/s and a FEC of 2/3 with approx. 20 watts.

    Best,
    Wilm

    Chris,
    no offense taken by me, and I'm pretty sure, no offense is taken by SG-Labs. Just lean back and be surprised what piece of electronics art you receive. His goods are masterclass.

    OK, communication is an issue, the goods are not.

    Some people are focused in communication, others build fine goods.

    So all good ;)

    Best,
    Wilm

    Kai,
    if you reduce the distance between reflector and patch, you will have less circular polarisation. So in your case, it doesn't matter, if you have mounted the patch the wrong way. With almost 20dB match, it is linear.

    I am using a Spectrian PA with approx. 70 watts and don't have any influence to the X-band. So the problem belongs to the Pollin-LNB itself. With either a Rocket-LNB, or a modified Octagon OQSLG, all works well.

    vy73,
    Wilm

    From my point of view,
    this was a simple test to stress the transponders by enemies of Qatar. Imagine, if a secret service will use the ultra-sensitive transponders for sending burst with secret messages...
    To affect the ALC in such a case, you really need power and gain from the antenna.

    A simple WiFi-jammer is using noise, not a high-speed pulse signal.

    I could recall, when Nilesat became on air, we had the same issues during the first month.

    Just my 2 cents,
    Wilm, DL4OCH

    Hi Peter,
    same observations here. I also can see a general degradation of the signals, except C/N.

    But, as we had massive storms over here (peak 122 km/h), I can't be sure, that my dishes are still aligned properly.

    The "sweeps" look to me, as somebody is trying to optimize a feed with higher power.

    Keep in mind, I was able to make a SSB-QSO with a 75cm dish @ 40mW. So this might be anything.

    Best,
    Wilm

    PS.: Measured with a "raped" CMU-200

    Hi all,
    as long he only transmits lyrics, I am fine with that. Callsign, yes or no. The problem will rise, if it will get political.

    The satellite is covering a lot of regions which are critical. Let's hope, non of them discovers this one as a proper medium, as the downlink is easy to receive.

    Either Leila, or an active notch might be a solution.

    As we transmit up to the sky, worst in the WLAN area, it is from my point of view almost impossible to discover the transmitter.

    We have to keep our fingers crossed, that it doesn't get worst.

    Just my 2 cents...