Posts by G0MJW

  • MY QO100 SETUP

    Quote from SV1BDS

    Hi,

    When I do DATV reception using a POTY feeder the MER drops to about 4 vs 10 without POTY. The same poty feeder receive NB fine. I have test various LNB and POTY feeders with out a conclusion. Any proposals or ideas?

    What lens are you using. Do you have it at the focus. The usual reason for this is the wrong lens for the dish or not having it as the focus by trying to reuse the existing LNB mount but not understanding the lens needs to be at the focus, not at some mechanically convenient point dictated by the original LNB holder.


    The reason it works for NB is the transponder noise floor is much higher so what you are losing on receive is not apparent. For DATV, the same effect applies, but only for dishes larger than 1.2m with efficient feeds. Therefore it is much much more critical to adjust the feed correctly. Beacon MER is a good indicator, but bear in mind it depends on transponder loading.

  • POTY vs HELIX

    Very interesting - but the focus of the POTY is not in the same place as the reflector but in the middle of the lens, so it needs to move a few mm back. This is probably why it is worse. That's a challenge mechanically with that feed arm because the reflector gets in the way. The Rocket lens might be better. did you measure the F/D ?

  • Pluto mit LAN Verbindung

    Quote from SV1BDS

    Hi,

    If the address is assigned by the router via DHCP then if you map the MAC to IP address at the router, the MAC address is belonging to the USB adaper not the Pluto. So if you have two adapters and two Pluto and swap them the addresses will match the USB adapters not the Plutos.

    Yes, That is true. I have noticed this, can be useful, or annoying, depending on the application. One hopes the one in the attic won't change.


    Mike

  • POTY vs HELIX

    Well OK - but the POTY was never intended for long focal length dishes so it's not surprising a helix does better. What is the F/D of that dish? It looks like 0.7-0.8 which makes sense for a 4.5 turn helix.


    I see have a VNA so why show VSWR ? It only gives you part of the picture. It simply perpetuates the myth popular amongst HF operators that VSWR is all that matters. It's a parameter but not the only one and not even the most important. We are better than that. From the VSWR I can't tell if the patch is tuned correctly, which will make up to 3 dB difference in the uplink it it's linear instead of circular. The other thing about that POTY is the reflector is not the recommended 105mm circle. It might be OK. I don't know.


    What is surprising is the difference on receive. The Helix should be worse but given that's not the recommended Lens on the POTY. I have never recommended anything like that, I can't see how it could work. If you don't follow the instructions, it won't work so well. HB9PZKs design is several dB better, as it the originally recommended Rocket Lens. If it really is so very many dB worse there is something not right - like the focal position or the wrong lens, or both. The feed looks too far forwards but that's not easy to tell from the Photo. The gain of LNBs varies widely so it's signal above noise that matters. A number in dBm is meaningless without knowing the gain. Was there some gain calibration done here?



    Mike

  • Pluto mit LAN Verbindung

    I am puzzled. None of my Plutos have addresses set up, they are assigned by my router based on the mac address of the lan router. It is set to remember and allocate the same address, but it doesn't have to be. If I want to change the default already defined I do that through the router, not the Pluto.


    Mike

  • DATV - mit Adalm Pluto und Software OBS - Studio Ton Probleme

    You are trying to get video in H264 in high resolution through a 125ks QPSK transport stream. That wont end well. You don't say what the FEC is but I think it is 2/3. Even without FEC 280kbs / s is not going to fit into 125ks QPSK (max bit rate 250k) in any case. More like 100k max. after FEC and overheads.


    Mike

  • Pluto mit LAN Verbindung

    Quote from DL3ED

    Hello everybody,

    does anyone of you know whether this adapter works on Pluto?

    10/100 / 1000Mb / s

    [attach = '6103', 'none', 'true'] [/ attach]

    Greetings Ulrich

    Looks like one I used. I use a OTG Y cable so can use standard USB plugs. It's a good solution.

  • BaMaTech Feeds - Unterschiede und Einsatzbereich

    It's very simple.


    If you want to transmit you need a feed that supports that. If you want to receive with the same antenna then you also need a feed that supports that too. A dual band feed, that goes to both up and downconverters.


    You only need 2x10 GHz if you want to receive narrow and and wideband as these are on different polarisations. A normal LNB feed does this switched by voltage. If you buy a feed with an SMA connection rather than with circular waveguide, then you need both horizontal and vertical polarisations, that is 2x10 GHz. You will also need a downconverter with a coax connector input rather than a waveguide input.


    You might find it instructional to look at the AMSAT-DL information documents which explain how to use the transponder and describe the equipment required.


    BaMaTech is not your only solution. It is also not the only one that can be bought rather than built. There are cheaper options and more expensive ones. There are options with helixes, horns and patches. There are one or two dish solutions. If you do go with BaMaTech, make sure it is the latest version with improved performance.


    Mike

  • SRI QRT via QO100

    Ah - I had not seen that - so Andreas is able to work duplex. This is good but still the TX and RX are decoupled so there is scope for a frequency error. If the transmissions appear on the WebSDR then Andreas is getting into the Transponder. The reference frequency is an odd one and might be outside the range of some PLL LNBs but assuming it is not and good reception is happening I go back to my original theory with respect to the cable or feed. Now I suppose it is possible that at very low elevation angles the 10GHz and 2.4 GHz will behave differently, but I do not think this is the case as long as there are no trees in the way. JP94 is a long way North but it's well within the coverage.


    For reference, I get into the narrow band transponder fine with 200mW, to a 2.4m dish. Taking into account the dish gains there is a factor of 7 so my 200mW should be about the same level as 1.5W to a 90cm. I struggle to send DATV at this power, it nearly works but only very low SR. To make the most of everything the Helix feed might be best for a long focal length dish. If we only knew when he was testing we could all take a look.


    Mike

  • SRI QRT via QO100

    The fog lifts - this is a problem with people who do not use SDRs but use upconverters and normal radios - they can not hear their own downlink because they are not full duplex. If there is any frequency error of more than a few kHz they can't work anyone because they call in the wrong place. It's really difficult to operate this way.

  • SRI QRT via QO100

    Firstly - with a 90 cm dish you should be able to receive well. You did not give any information about your dish? 90 cm is not sufficient information. You may see another 3dB with the POTY or a helix but I don't think that is your problem. I think your problem is either you do not actually have 1.5W at the feed or the dish is miss-pointed. If 10 GHz works well we can rule out miss-pointing. In that case the only thing it can be is the transmitter is not working.


    Apart from the dish information

    How do you measure the 1.5W?

    How did you verify it is on the correct frequency?

    Is there any cable between the transverter and the dish? If so exactly (YES, EXACTLY) what is the cable?


    The reason I ask about the cable is sometimes they can be very lossy, or have bad connectors. IF there are SMA connectors and it is a WiFi cable the SMAs are often reverse polarised and won't work with regular SMAs. This catches many people out.


    Mike

  • SRI QRT via QO100

    Does not work with 1.5W? It does with a suitably large dish - say 1.2m or above. It should also work with 90cm. What is your feed?


    Mike

  • MiniTiouner E-Tiouner von ELAD - HW-Test

    Quote from DD4YR

    What about the heat development?

    BATC V2 uses a switching converter so this should not be an issue.



    Quote from ik1hgi Tony

    Last night I did a test to see if the Miniatiuoner receives the 5.7ghz but nothing to do !!!! only 2.7ghz sin after so many tests nothing to do only with the DVBS-GUI program and perfect let's see if in the future the possibility to see on the miniouner

    73 ik1hgi Tony

    Seems strange to be negative about a receiver specified 14-MHz to 2.4 GHz not working at 5.6 GHz. That's like complaining your HF RIg doesn't work on 23cms. I have used my BATC V2 on 24 GHz with no problem, working at the Transverter IF.

  • MiniTiouner E-Tiouner von ELAD - HW-Test

    I made that board. It's not the most modern though. We have been busy of late developing new hardware. It depends if you want to build something, (the BATC minitiouner is a very easy project), or buy something ready built. For example the new mini French tuner is a good deal.


    In the UK we now have:


    - The BATC Ryde which uses a Raspberry PI with a minituner and goes a step further in also being able to display the images, like a set top box.

    - The Portsdown 4, which adds a Pluto to a PI4 and can transmit SSB / CW / FM / DATV, receive SSB / CW / FM and when coupled with a miniature receive reduced bandwidth DATV, all controlled by a touchscreen.

    - In development, the Winterhill which integrates a PI4 with one or two tuner modules to decode up to 4 signals at once and another single channel receiver which is going to be really interesting for terrestrial work.


    Lot's of choices.


    Mike

  • Ausleuchtungszone von QO-100

    Beachten Sie für die Abdeckung, dass der Horizont auf Meeresspiegel eingestellt ist. Wenn Sie höher sind, ist die Abdeckung größer. Das hilft nicht viel, aber es hilft ein wenig.