Posts by G0MJW

  • Adalm Pluto SDR + SDR Console Remote

    It occurs to me some people may not know how to do this. You need an OTG Ethernet adapter and a Y-cable for power. Don't try to power from the Pluto, it may work but often doesn't, at least not reliably. Pluto will use DHCP to get an IP address from your router. Find out what it is and enter it in SDR Console. Set up will look something like this highlighted:



    The difference is the IP address.


    Mike

  • Adalm Pluto SDR + SDR Console Remote

    Of course. Just use a Pluto on your network and connect with WiFi at 5 GHz. I do this all the time. If narrow band, best limit the bandwidth. If DATV lower SRs are better, but in 2021 there is really no need to run 1Ms/s.


    Mike

  • 30cm camping offset dish with POTY

    Old thread but there is no lens supplied. The POTY feed is a design, it is not a product. There are people selling implementations of the design and sometimes with lenses that may or may not suit the dish being used. It is necessary to make/buy something that suits the dish focal length. Typically the lens from a Rocket Type LNB works well with satellite TV dishes but these are getting hard to find. The HB9PZK lens in Rexolite is good performer.

    The other common mistake is not understanding the feed and lens needs to be at the focus and simply clamping the LNB with the original clamp and with the POTY sticking 6 inches out in front. That's never going to work and I honestly never thought anyone would make such a mistake, but I was mistaken..


    Mike

  • IS0GRB Use OBS in H265 without dedicated board

    That's interesting as I appear to be getting full HD out of the OBS camera plugin, at least according to VLC and it certainly looks full HD. However I tend to use lower symbol rates so the limit becomes the channel.

    Using OBS camera is a fudge though, as it record, RTMP etc. The internal (non-plugin) OBS camera didn't include an audio channel, when I asked it hadn't even crossed their minds that this might be useful.


    It would be good if someone could get inside OBS and get it to produce a TS on it's own, the DATV plugin... the developers seem rather against this whenever I have asked about anything like that though you would think there would be a demand outside amateur use. Maybe it just needs a lot of people to ask.


    Mike

  • Solved: Pluto F5OEO Firmware plus frequency extension 70MHz to 6GHz -- how?

    Well I did wonder. I am not aware it doesn't allow that. It could be Evariste does is automatically. I think you just use the standard commands. If that's actually the case it's simple enough to load the earlier version via the USB drive and eject and apply the standard command. Google should have found this as the top hit, at least it did for me


    Adalm Pluto -New official firmware 0.32


    Advice - use 0.31


    Mike

  • LNB REF signal (TCXO inside the LNB & Ref fed by the duplex) has an effect on the output signal.

    Yes - that's expected if the reference is not of very high quality or it's not being fed in at the right level. Incidentally that LNB looks more like a DRO based one than a PLL based one but I assume it is a PLL. The quality of the 25MHz is critical. Any noise on it is multiplied many times. For DATV use you are often better with a standard unmodified PLL LNB. This often shows up in the MER on the beacon.


    Mike

  • H265 hard or/and software problem

    Here is my Bat file for 160kb/s. I see several differences.


    c:\ffmpeg\bin\ffmpeg -f dshow -i video="OBS-Camera" -thread_queue_size 512 -f dshow -i audio="OBS-Audio" -vcodec hevc_nvenc -s 1280x720 -bf 0 -pix_fmt yuv420p -b:v 80k -r 10 -preset slow -profile:v main -rc cbr_hq -rc-lookahead 5 -acodec aac -aac_coder twoloop -ar 48000 -ac 1 -b:a 24k -f mpegts -muxrate 160k -streamid 0:256 -streamid 1:257 -max_delay 2500000 -pcr_period 40 -pat_period 0.4 "udp://192.168.1.46:8282?pkt_size=1316"


    You have that extra buffer and a very different network address. I tested this to VLC, it took a good while to appear but worked OK. So then I tried yours, modified to send to 127.0.0.1:1234. It also worked fine. So is it the IP address? Firewall maybe?

  • 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 ?

  • 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

  • Software DVB-S demodulator

    Quote from G0MJW

    4Msymbols. It locks fine. I just doesn't decode the data.

    This is not on the satellite. It's DVB-S local repeater. Line of sight, 20 dB C/N. No multipath. Rarely it gets a frame but soon loses sync. I have given up as I don't think the package is able to do this at the moment. Something is probably broken so I will wait for the next version.

  • Software DVB-S demodulator

    I just can't get this last version to work in DVB-S. It locks to the signal, nice clean constellation, but it refuses sync. Does anyone know if this actually works in DVB-S? 4Ms?