New DATV Beacon Parameters

[G8GKQ]

The DATV beacon parameters were amended this morning (25 March) to free up more spectrum on the transponder for users. The new parameters are:

• Modulation: DVB-S2 QPSK
• Frequency: 10491.5 MHz
• SR: 1500 kS
• FEC: 4/5
• Rolloff: 0.25

This requires a C/N of 4.6 dB for decoding, but the beacon power density has been increased so that reception should still be possible on dishes of 80 cm and larger.

A new bandplan will be published in due course, and the Wideband Spectrum viewer will also be amended.

I hope to issue a new Portsdown version to take account of the changes in the next few days.

Thanks to the AMSAT-DL team for all their work to make this happen.

Dave, G8GKQ

[g4hiz]

Dave

Beacon lovely carrier this morning (07.30), D6, MER 10.7/10.9dB on 1.2m prime-focus.

The 1.5Ms/s is a nice rate; would it be possible to have a Portsdown default Tx setting for 1.5Ms/s, instead of say 3Ms/s ?

73
Jen G4HIZ

[G7JTT]

Hi Jen you can change default SR values already "Menu3" then "Set Preset SRs", hopefully I've understood correctly what you want ?

All the best and stay safe John G7JTT

[g4hiz]

Hi John,

absolutely right ! The flexibility of this system never ceases to amaze me; a tribute to Dave's hard work !

Indeed, keep safe all !

73
Jen G4HIZ

[G8GKQ]

I have just released a new version of Portsdown Buster 2020 that has been amended for the new QO-100 Beacon frequency and SR. So the LNB Offset Autoset and the Beacon MER display will both work after software update or for new builds. Simply update from Menu 3, Check for Update.

New builds also include the revised beacon frequency and SR in the list of presets. This will not be included in the update so as not to over-write your current presets. If you wish to, you can amend these figures yourself (RX, Config, Set Preset RX Freqs and Set Preset RX SRs).

Note that I have not updated Portsdown Stretch 2019 yet.

Remember that the Beacon video is not displayed on the Portsdown - it can't handle the full HD as transmitted by the beacon, although you can view it on a PC using UDP to transfer it to VLC.

Dave, G8GKQ