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

See comment/description of video: Working GB3ZZ 437 MHz input 2021-07-14
1280 x 720 progressive 30 fps MJPG
- Could effect bandwidth or CPU usage.

Videos

VLC

Useful command to check VLC ports: watch -d "sudo lsof -i -P -n | grep vlc"
https://wiki.videolan.org/Documentation:Streaming_HowTo/Command_Line_Examples

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.
Update: 2021-08-16: 70 cm input is no longer active.
Update: 2021-09-01: GB3ZZ site decommissioned. TODO: Find exact date.
Update: 2022-01-10: GB3ZZ recommissioned on adjacent building. Exact heights, bearings and ranges TBA. Currently running in TX only beacon mode with no RX enabled.

Band	Direction	Name	Availability	Frequency	Standard	Symbolrate	Video codec	FEC	Antenna	Polarisation	Device
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

Working the 23 cm input

Above I mention working the 70 cm input. I also worked the 23 cm input a few days later. TODO: Video coming soon.

Links and diagram

ATV, SDR,

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