Repeater input bandwidths
Posted: Wed Jan 23, 2019 10:56 am
All,
With the significant improvement in video coding quality and the availability of MPEG-4 (H264) equipment (Portsdown) I think it's time we considered the specification of our repeater inputs - the current recommendations were made in 2002.
Most of us are running 4Ms (~4.5MHz) on 23cms and 2Ms (~2.25MHz on 70cms) and I think it's realistic to drop these to 2Ms on 23cms and 1Ms H264 on 70cms.
The instant benefit is a 3 dB gain - try getting that from improved antennas - and by using H264 there is no drop in video quality!
The reason for suggesting it now (and it is a suggestion) is that the new Portsdown 2019 with a LimeSDR Mini struggles to do MPEG2 above 1.5 Ms but will do H264 in 2Ms.
So the big question is can anyone recommend an H264 / MPEG-2 receiver which they have completed lock indicator mods on that we can all use?
73
Noel - G8GTZ
With the significant improvement in video coding quality and the availability of MPEG-4 (H264) equipment (Portsdown) I think it's time we considered the specification of our repeater inputs - the current recommendations were made in 2002.
Most of us are running 4Ms (~4.5MHz) on 23cms and 2Ms (~2.25MHz on 70cms) and I think it's realistic to drop these to 2Ms on 23cms and 1Ms H264 on 70cms.
The instant benefit is a 3 dB gain - try getting that from improved antennas - and by using H264 there is no drop in video quality!
The reason for suggesting it now (and it is a suggestion) is that the new Portsdown 2019 with a LimeSDR Mini struggles to do MPEG2 above 1.5 Ms but will do H264 in 2Ms.
So the big question is can anyone recommend an H264 / MPEG-2 receiver which they have completed lock indicator mods on that we can all use?
73
Noel - G8GTZ