DATV DVB-S transmission into GB3ZZ

by on under hamradio
6 minute read

DATV DVB-S transmission into GB3ZZ

This post is a continuation of A state of tuners but with a focus on VLC RTP, GB3ZZ and DATV transmission. I suggest reading my previous post first.

Current setup

Videos

VLC

Local

It wouldn’t accept dvb-adapter on the same colon spaced so had to be a separate flag.

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 --dvb-adapter=1

Program has to have a space before.

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 :program=2 --dvb-adapter=1

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 :program=1 --dvb-adapter=1

I eventually found I could use colons for adapter provided its also spaced.

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 :program=2 :dvb-adapter=1

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 :program=1 :dvb-adapter=1

The following two commands did not work for me.

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 :program=2 :dvb-adapter=1 --sout rtp/ts://localhost:9090

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 :program=2 :dvb-adapter=1 --sout http/avi://localhost:9090

Remote

Got this one to work for one channel.

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 :program=2 :dvb-adapter=1 --sout '#rtp{dst=192.168.1.173,port=1234,sdp=rtsp://192.168.1.137:8080/test.sdp}'

These work for multi channels although I found the latter works without the need for --sout-all

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 :dvb-adapter=1 --sout '#rtp{dst=192.168.1.173,port=1234,sdp=rtsp://192.168.1.137:8080/test.sdp}' --sout-all

vlc dvb-s://frequency=1316000000:srate=4000000:dvb-fec=1:voltage=0 :dvb-adapter=1 --sout '#rtp{dst=192.168.1.173,port=1234,sdp=rtsp://192.168.1.137:8080/test.sdp}' 

Client command: vlc rtsp://192.168.1.137:8080/test.sdp

I could also do multicast but I am sticking to unicast as I only intend to watch it on one machine and want to save bandwidth on my LAN.

Notes

  • RTL-SDR wont work due to 2.4 MHz band width limitation for GB3ZZ as ZZ TXs 4 MSps which is around 5 MHz bandwidth.
    • I can however use a RTL-SDR + SDRangel for local TX monitoring of my 1 MSps signal.
  • I wonder if HackRF libraries are what slow down SDR angel.
  • TODO: Try pluto with SDRangel.
  • Blazer HD4000 will go down to 1 MSps.
    • It will also go down to 437 MHz and a bit lower.
    • 10000 (Mhz lnb freq in software) + 437 (Mhz freq we want to receiver) = 10437 is the frequency we input into the box so it can account for lnb down shift.
    • However its input sensitivity is rather bad that low down.
  • It’s worth monitoring the TX output spectrum of your TX device, in my case Pluto SDR.
    • I found sometimes it transmits a bit wonky, e.g. broken up signal. In that instance DATV Express needs restarting to fix it.
  • I can get 2 MSps with h262 but not h264 on my Pluto.
    • h265 I hit CPU limitations on my host PC.
  • Blazer works on h262 and h264.
  • I haven’t yet gotten 333 KSps to work yet locally. 1 MSps TX works best however I should check the 333 issue isn’t a DATV Express restart issue. Otherwise it maybe just SDRAngel.
  • Ryde receiver no dual channel support?
  • Observed setups
    • TX: DATV Express -> LimeSDR. RX: FreeSAT.
    • TX: FR Systems
    • TX: DTX 1. RX: FreeSAT.
  • Ports down
    • A semi umbrella term for a project which can consist of different transmitters.
    • Multiple versions of ports down exist see links section.
    • LimeSDR
    • Pluto SDR
    • DATV Express TX board
    • MiniTiouner receiver board
    • Raspberry PI running custom OS
  • The handheld “Satellite Signal Finder” I been informed go down to 1 MSps and 437 MHz.
  • h262/MPEG2 are the same.

GB3ZZ extended details

Note this information is subject to change and should only be viewed as a snapshot of the current setup at time of writing.

  • The 1249 input is more sensitive because the aerials are much higher and there is a hot pre-amp up the mast.
  • Big wheel omnidirectional horizontal antenna for 437 MHz input.
    • Height is same as the 2 m talk back antenna approx 2-5 ft off the roof of the building.
  • Height for 23 cm input antenna is 20 ft off the roof.
  • 08:45 BATC streamer reboots and then again at 16:45. Reboot takes approx 5 mins.
  • The big wheel antenna is the only working one at the moment? The Yagi heading towards Minehead doesn’t work?
  • There is an automatic antenna switcher for 437 MHz input.
    • 10:57 - 12:57 Yagi facing Minehead is active.
    • 17:24 - 19:54 Yagi facing Minehead is active.
    • The above times are in effect Tuesday to Saturday.
    • The rest of the time big wheel is active.
    • At all times 23 cm input overrides this so you can operate 23 cm input at any time of day.
    • In other words
      • When pictures of Bristol are showing on GB3ZZ the big wheel antenna is active.
      • When GB3ZZ test cards are showing on GB3ZZ the Yagi facing Minehead is active.
  • Ryde receivers only active from 07:00 - 23:00 during summer time. They’re subject to BST.
  • 23 cm input and output faces?
  • 23 cm output height off roof?
  • The 144.750 MHz VHF FM vertical is for talk back. This gets fed into the TS (Transport Stream) of GB3ZZ output.
  • Rydes can take 30 seconds to switch as they’re scanning multiple modes.
  • Output is two channel multiplexed. Channel 1 is the main channel and has audio left and right separate sources. Channel 2 has no audio normally and is the engineering channel.
Band Direction Name Availability Frequency Standard Symbolrate Video codec FEC Antenna Polarisation Device Notes
23 cm Output Primary 24/7 1316 MHz DVB-S 4 MSps h262 1/2 Yagi Horizonal    
23 cm Input Primary 24/7 1249 MHz DVB-S 4 MSps h262   Yagi Horizonal Satellite box  
23 cm Input Secondary 06:00 - 22:00 1249 MHz DVB-S/S2 2 MSps, 1 MSps or 333 KSps h262/h264/h265   Yagi Horizonal Ryde reciever  
70 cm Input Primary 24/7 437 MHz DVB-S 2 MSps h262   Wheel/Yagi switched Horizonal Satellite box  
70 cm Input Secondary 06:00 - 22:00 437 MHz DVB-S/S2 1 MSps or 333 KSps h262/h264/h265   Wheel/Yagi switched Horizonal Ryde reciever  
2 m Input Primary 24/7 145.750 MHz FM N/A N/A N/A Collinear Vertical    

antennas

Portsdown 4 diagram

ATV, SDR,
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