Posts by G0MJW

  • My LNB modification nightmare...

    Adapting the LNB tp POTY - you can hacksaw off the horn or press it the feed into the horn. You will need to adapt the mounting of the LNB to fit and take it further back if needed. Before you start, establish the location of the focus with the supplied LNB. This will be more of less flush with the front of the horn. Any mount you make should allow for easy adjustment.


    Best LNB - problem here is that's a movable target and even the same make and model LNBs are not always the same inside. Octagon PLL seems the most common. The single or Dual appear the easiest. Lots of others have had success with other models. There is a Wiki on this on the web. Just do a google search.

  • Octagon SF-8008 with low SR

    Quote from M1CTK

    So hard to get Tomasz to reply, it seems with a 9ghz LNB you can enter the frequency, this one for example https://www.aliexpress.com/ite…1602_1,searchweb201603_55 you can enter the correct frequency ?


    But still trying to find what Linux image is being used in the screenshot I posted, anyone ?

    I guess my reply was not sufficient as you keep asking the same questions and expecting someone else to reply. This is my last attempt.


    The LINUX image is directly linked to above in this thread by OE7DBH. There are now at least two working images that to kHz. I have pasted the information below again.


    The 9 GHz LNB you posted a link to does not look like a PLL LNB It might be but I doubt it.


    Mike



    SF8008 Receiver owner: :)

    http://forum.dxtv.de/wbb/threa…t=&hilightuser=0&page=169

    Please test new software, new software allows kHz input and thus exact frequency setting to 250 or 333 kSym is much easier.  So far, the smallest step was 1MHz

    Please download software here... http://openeight.de/index.php?open=sf8008



    Your experience with it, please post here !!!!!!



    Thank you to the Octagon support team !!



    ( "zuerst mal manuelle, auto, satfinder... alles durchtesten (nebenwirkungen etc.) danach kann man auch Kanallisten und blindscan angehen" - first manual, auto, satfinder ... everything by testing (side effects, etc.) then you can synonymous blind scan and channellist approach. )

    Images

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  • Adalm-Pluto

    If you are referring to the new firmware that uses RTMP stream, the power is a parameter on the stream command. If you are using the UDP method, there is a web interface to set power and frequency. Just login to the Pluto web server (just type it's IP address into a web browser) and follow the link.


    Mike

  • My LNB modification nightmare...

    Willi did a very good analysis - it is really important to get the 10 GHz focus in the correct place and that is not always easy to achieve, especially when manufacturers do not publish the information. Best stick to dishes that have been successfully tried and tested where this information is available.


    Mike

  • BaMaTech DuoBand-Feed: receive poor?

    If the dish really is 0.4 f/d then the lens you need will be one of the very short ones. I am surprised this 80cm sky dish has such a short focal length but as it does it will be a fairly good match to a patch feed. What worries me more is there is there is such a big difference between your feed and the standard LNB. A standard LNB would be a very poor match to a 0.4 f/d dish as it would serriously under-illuminate it. You would expect the situation to improve, not get worse. Was the LNB supplied with and perhaps matched to the dish?

  • Octagon SF-8008 with low SR

    I have just remembered that even the standard firmware allows you to enter the frequency - but only to a resolution of 1 MHz. The new firmware allows to to enter kHz too. This helps at lower SR but the receiver has a wide lock range so it will usually lock to the strongest signal of the right symbol rate.


    There is a link to this new firmware elsewhere in the forum. Once you have set your LNB LO frequency to bring the IF into the tuning range of the SF8008 don't forget to set this new LO frequency in the settings - e.g my LO is 9.5 GHz so I set my SF8008 LNB LO to that. Then I can enter the correct receive frequency in the setup menu.


    To help, there is a list of common frequencies already set up as a bouquet you can load which makes tuning much easier.


    Mike

  • Octagon SF-8008 with low SR

    I expect he has installed the new firmware noted earlier that allows you to enter the correct frequency, which has to be in the 950MHz-1.75 GHz range of the tuner. A standard LNB will give an IF of 739 MHz whuch the SF8008 can't tune (nobody has found a way at least). You need to modify the LNB or use a frequency converter. For example, a 24 MHz reference into a normally 25 MHz PLL LNB will move the IF into the range of the SF8008. I think we have been around this loop before - I know your other receiver can do it but this one can't yet.


    Mike

  • BaMaTech DuoBand-Feed: receive poor?

    Quote from DL9SEC

    I can not see the real advantage using the POTY, because the 10GHz feed is very similar to that of BaMaTech.

    Maybe a solution with a standard LNB and a helix could be better for you...

    No! The POTY 10 GHz arrangement is very different. The POTY was specifically designed to use a dielectric rocket style lens right from the very start. If you don't follow the design, it won't work. It is also designed to have circular polarisation at 2.4 GHz, hence the shape. Considerable thought and a lot of EM simulation resources went into the process. The design was a compromise between performance and complexity and intended for satellite TV dishes with f/d from 0.5-0.6. It's possible to do better, but that needs more complex mechanical construction.


    A dual band helix was specifically rejected because the helix blocked the 10 GHz in an difficult to predict way and avoiding that put the phase centres quite far apart. For single band, a helix is likely to be best on 2.4 GHz and a standard LNB horn on 10 GHz.

  • BaMaTech DuoBand-Feed: receive poor?

    I am not surprised - where is the 10 GHz lens ? There isn't one! This feed will not work with a long focal length dish. It is a design for a deep dish only. Get a rocket style LNB, take the lens and fit it to the feed, or use one of the lens designs elsewhere on the forum.


    Is the feed at S-band really circular polarisation?


    Mike

  • WB TRANSPONDER TESTS

    We have done 32APSK before back in the early days but the problem with it is the high SNR and limits of phase noise. 16APSK is the more realistic limit. 33ks at 16APSK is quite watchable as long as the resolution is not too high. Better though to stick to 8PSK or QPSK and a slightly higher bandwidth.