BATC Forum

It must be Christmas!

As well as news of a ATV satellite transponder in 2016, the Ofcom document available here http://stakeholders.ofcom.org.uk/binari ... tation.pdf says the following:

4.28
The Radio Amateur community have made a case for utilising additional spectrum to develop new digital technologies for voice, data and video and we have considered this request carefully. We propose to make around 1 MHz of spectrum temporarily available with restrictions through a time limited Notice of Variation (NoV) for full Amateur Radio licence holders. We propose to make available the spectrum from 146 to 147 MHz for this use. This is adjacent to the existing Amateur Radio allocation at 144 to 146 MHz.

Good news but note the following:
4.33.3 Maximum power of 25W ERP referenced to a half wave dipole...

And a closer look at the map on page 32 shows some geographic restrictions including the Bournemouth and Isle of Wight... We won't be working G4KLB on the new band ;-(

Great news.

I imagine it will have to be H264 / DVBS-2 at least. Are there any DVB-T2 modes that go to such a narrow bandwidth?

Brian

We still need to reply to the consultation paper. I am going to suggest the power level
be stated as dBm/Hz in the hope we can get a bit more power allowed for DATV.

Although I will apply for a NoV I have banned areas to the east and west of me and hills directly
north of me and France to the South so I suspect the probability of having a QSO will be zero
but at least I will be able to show to OFCOM that if they give us the spectrum we will use it
even if it is only for a year.

No there are no T2 modes that narrow and most satellite receives won't work below about
600KSymbols/sec so it is going to have to be SDRs and designer software probably based
on GNURadio (the only way I can think of rapidly producing a new protocol without a huge
amount of coding).

- Charles

I see that they did the QRM tests with an omni-directional antenna, presumably vertical. Horizontal would be more appropriate for ATV, though probably not for other data modes.

Perhaps there could be a different power limit for horizontal. I'm not sure if clause 6e is relevant.

Brian

(6e) If the Licensee can demonstrate that the use of the Station in the Authorised Band
complies with relevant provisions of the Harmonised Calculation Method agreement,
it may be taken to show that the use of the Station in the Authorised Band is not
breaching the agreed international coordination limits applicable to the Authorised
Band.

Ok how about this...

One alternative is the use of rather lower power than 25W erp that could let you roll back the restricted blocks....

Apart from that - read all the small print!
For example there is also an upper band-edge restriction in Scotland; and...
Not many GIs use UK-NGRs (as Irish Grid is more common there) etc

If a more likely bandwidth is 0.25 to 0.5MHz (allowing for other use ot duplex) then dont forget other image/video formats, inc IP streams

First step though - say YES to Ofcom Question-4

regards

Murray