Es'hail-2 conference transmissions

From BATC Wiki
Jump to navigation Jump to search

It has been agreed by AMSAT-DL that the wideband transponder can be used to uplink amateur radio related conferences and presentations.

Any transmissions must be agreed with AMSAT-DL before the event and should last no longer than the actual conference or talk sessions - transmissions of empty rooms and / or general activities are not permitted as they are taking up transponder bandwidth which could be used for normal DATV QSOs.

A valid amateur radio callsign must be transmitted at all times (either in the SI or on the screen) and it is the user's responsibility to check and comply with their local license conditions.  For example the UK amateur radio license does NOT permit broadcast transmissions and all transmissions must either be a CQ call or a two way QSO.

The event should be publicised as much as possible on social media and the AMSAT-DL forum and BATC forum.

A special event streaming channel can also be arranged on the BATC streamer and this can be streamed from either directly from the event or a ground station using MiniTiouner and the ffmpeg script.

Transmission standards

The aim should be to ensure anyone capable of receiving the beacon should be able to receive any conference transmissions. To achieve this, the conference uplink should use the following transmission standards:

  • Transmission mode: DVB-S2 (Increases the signal margin by 2 dB and is the recommended standard for QO-100)
  • Modulation: QPSK (gives the best signal margin)
  • Symbol Rate: 1.5MS (Higher SR needs more power/TX dish size and denies other users the bandwidth. Lower SR reduces compatibility with commercial receivers and potentially reduces video quality.) 1.5MS also reduces any conflict with the 2MS beacon which can pull receiving station’s tuning off channel.
  • Frequency: The exact frequency to be used will be confirmed at the time of request, but the nominal frequency for conference transmissions when the beacon transmission is on is uplink 2405 MHz, downlink 10,494.5 MHz with a 0.2 roll off. When the beacon is off (by arrangement) the beacon frequency should be used.
  • Encoding: H264 (H265 would give better picture quality, but increases encoding complexity and decreases receiver compatibility).
  • Power Level: The power level should be set to the same as the beacon (using the Spectrum Monitor here: ). This means that anyone who can receive the beacon should be able to receive your transmission.
  • FEC: 2/3
  • Picture format: 720p.
  • Power budget: About 100W to a 1.2M dish should achieve the parameters above (or 25 W to a 2.4M dish...)