BATC Net on QO-100

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G8GKQ
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Posts: 1921
Joined: Sun Mar 22, 2009 1:21 pm

BATC Net on QO-100

Post by G8GKQ » Tue Mar 17, 2020 12:04 pm

In the current circumstances I think that it important that we increase communication between our members. As a starting point, I would like to propose a BATC net on QO-100 at 8pm - 9 pm (UK) every Thursday evening.

The ground rules are that maximum transmit time per station is 5 minutes and the subject should be "current amateur radio activity". So describe your latest construction project, or simply talk about what is happening on the amateur bands from your perspective. Technical experimentation during the net will be discouraged - that can take place one-to-one elsewhere on QO-100. For maximum compatibility, the following parameters are recommended:
  • Downlink Frequency 10499.25 (or as high on the transponder as is available)
  • Modulation DVB-S2
  • Symbol Rate 333 kS
  • FEC 1/2
  • Encoding H264
Use of these parameters should mean that transmissions will be easily received on an 80 cm dish with a MiniTiouner and a Raspberry Pi.

Transmissions will be coordinated through the online Es'hail-2 WB chat channel https://eshail.batc.org.uk/wb/.

Dave, G8GKQ

G7JTT
Posts: 231
Joined: Fri Jun 10, 2016 5:05 pm

Re: BATC Net on QO-100

Post by G7JTT » Tue Mar 17, 2020 12:27 pm

Great idea I'll have to setup my scripts to enclude a H264 encoding. See you Thursday night 👍

g4hiz
Posts: 67
Joined: Thu Oct 18, 2018 6:40 am

Re: BATC Net on QO-100

Post by g4hiz » Wed Mar 18, 2020 5:39 pm

Great idea Dave !
It will be my first uplink since updating Buster to the latest build. H264 is the standard for my set-up, so no prob. See you all there.

73
Jen G4HIZ

g8gtz
Posts: 1364
Joined: Wed Apr 07, 2010 6:26 pm

Re: BATC Net on QO-100

Post by g8gtz » Thu Mar 19, 2020 10:50 am

Don't forget to join the net tonight.

All stations will hopefully be streamed to enable everyone to watch.

https://batc.org.uk/live/oscar100net

73

Noel - G8GTZ

g0mjw
Posts: 1444
Joined: Sat Sep 20, 2014 9:15 am

Re: BATC Net on QO-100

Post by g0mjw » Thu Mar 19, 2020 4:43 pm

G8GKQ wrote:
Tue Mar 17, 2020 12:04 pm
In the current circumstances I think that it important that we increase communication between our members. As a starting point, I would like to propose a BATC net on QO-100 at 8pm - 9 pm (UK) every Thursday evening.

The ground rules are that maximum transmit time per station is 5 minutes and the subject should be "current amateur radio activity". So describe your latest construction project, or simply talk about what is happening on the amateur bands from your perspective. Technical experimentation during the net will be discouraged - that can take place one-to-one elsewhere on QO-100. For maximum compatibility, the following parameters are recommended:
  • Downlink Frequency 10499.25 (or as high on the transponder as is available)
  • Modulation DVB-S2
  • Symbol Rate 333 kS
  • FEC 1/2
  • Encoding H264
Use of these parameters should mean that transmissions will be easily received on an 80 cm dish with a MiniTiouner and a Raspberry Pi.

Transmissions will be coordinated through the online Es'hail-2 WB chat channel https://eshail.batc.org.uk/wb/.

Dave, G8GKQ
Just tested with recommended settings and OK with reduced performance over 2/3 FEC (and H265) but it will do for a net. Can people also please stick to standard resolutions and aspect ratios so that they display properly on satellite receivers like the Octagon. e.g. 1280x720, 640x360, 1920×1080 etc.

If there is any interest, we can demonstrate the possibility of sending 2560x1440 in 500kHz using 8 PSK and H265 afterwards.

G8GKQ
Site Admin
Posts: 1921
Joined: Sun Mar 22, 2009 1:21 pm

Re: BATC Net on QO-100

Post by G8GKQ » Thu Mar 19, 2020 4:58 pm

Hi Mike

Pure Portsdown users will be 704*576. The RPi H264 encoder needs line length to be divisible by 32

Dave

g0mjw
Posts: 1444
Joined: Sat Sep 20, 2014 9:15 am

Re: BATC Net on QO-100

Post by g0mjw » Thu Mar 19, 2020 5:07 pm

That's probably OK as it's standard, 576p. It's where the resolution is not a standard that the picture doesn't fit properly.

g8gtz
Posts: 1364
Joined: Wed Apr 07, 2010 6:26 pm

Re: BATC Net on QO-100

Post by g8gtz » Fri Mar 20, 2020 10:16 am

Well that was fun if rather chaotic in the G8GTZ shack where I was trying to run the stream and have a QSO - not too mention I'd unplugged the Portsdown network cable so no IPTS input and trying to montoring the stream via a laptop connected via 2.4GHz wifi :D

Last night the stream at https://batc.org.uk/live/oscar100net was running by taking the UDP output from MiniTuioner in to an ffmpeg which sent it off to the streamer - this has worked OK in the past but doesn't seem to like the rapid changeover between stations on the satellite. This caused the stream to drop, clitching and freezing.

For future weeks I plan to run Vmix which will provide a constant stream.

Also it was just too confusing having 2 chat windows to monitor and so in future I'll disable the chat on the BATC streamer and all comms should take place on the QO100 spectrum monitor https://eshail.batc.org.uk/wb/ which is where the transmitting stations were monitoring and Dave was co-ordinating the net!

A good first effort and hope to see lots more people on next week.

73

Noel G8GTZ

G8GKQ
Site Admin
Posts: 1921
Joined: Sun Mar 22, 2009 1:21 pm

Re: BATC Net on QO-100

Post by G8GKQ » Fri Mar 20, 2020 10:19 am

Thanks to all who came on last night!

G4HIZ, G0MJW (featuring F5OEO), G4KLB, G7JTT, G4BAO, G0DQH, G8GTZ, G4CPE and myself, with G4EML and M0DNY appearing after the net had closed.

Really useful to highlight issues in current systems (like my picture quality!), and also to keep community informed.

Look forward to seeing you all next week, on 10499.25.

Dave, G8GKQ

g4eml
Posts: 333
Joined: Thu Apr 26, 2018 9:36 am

Re: BATC Net on QO-100

Post by g4eml » Fri Mar 20, 2020 11:22 am

Although I didn’t get my Portsdown working until after the net, I was watching.
I had the same problems with minitioune as others. It was very reluctant to lock onto new transmissions. Loss of sound was also common.
It looks like minitioune hangs on to the last received signal format for a long time and has to be forced to acquire a new one. Clicking the PID switch usually worked. For this type of ‘quick over’ operation it was not ideal.

Viewing and listening with VLC was a slight improvement but still not great.

I wonder if the choice of FEC 1/2 was anything to do with the sound issues. It also seemed to cause problems with picture breakup with movement. Maybe worth trying another setting to get a little more headroom.

Overall though it was an interesting first attempt.

Colin G4EML

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