In all innocence I earlier tweeted a picture of a commercial video coder/modulator. I was told in good faith that it should be suitable for use within the new 146-147MHz ham band allocation, when frequency translated from its current 70MHz. I should have followed my inititial instincts that it wouldn't be suitable when using QPSK modulation, even at rates significantly below 1Msymbols/sec.
It seems I innocently walked into an ongoing debate between some parts of BATC and the RSGB.
It can be done, but it seems that what was being proposed would be unsuitable in view of the difficulties of achieving a suitable SPD at the band edges and consequent potential interference to safety of life services operating above 147MHz and our fellow satellite enthusiast just below 146MHz.
Whilst not wishing to discourage anyone from using DATV in the new band ( or indeed 10 or 6m) it looks like more effort needs to be put into solving the spectrum occupancy issues. This is what radio amateurs are good at.
It seems to me that the current wish to use a number of free ex-commercial coder/modulators may be clouding the real issues.
It should be added that I am referring to fast scan digital TV. Slow scan variants look fine but may not offer anything new or innovative and hence not enhance our case to keep 146-147MHz in the future, or indeed give us a bit more spectrum in this region.
I hope these issues can be overcome and a real solution found.
Finally, these are my personal views and do not represent those of any organisation.