?? IARU Region 1 1999 Lillehammer Conference Report
By Graham Shirville, G3VZV
The International Amateur Radio Union Region 1, which is responsible for all of Europe and Africa, holds a Conference every three years. This year?s Conference was held in Lillehammer in Norway and included debate on over one hundred different proposals and ideas that had been received from most of the member Societies. Subjects covered included VHF and HF contest rules, amateur satellite and space stations frequency allocations, band plans in general, plans for the future defence of amateur bands and even the vexed question of keeping the morse tests for HF licences. Full information on the Conference proceedings is available from the following website: my.genie.co.uk/g3znu/iaru/conference.html. This has been linked from our BATC website already for some weeks.
|Opening Plenary Meeting|
There were two subjects which had a particular bearing on ATV operation were discussed by the C5 VHF/UHF/Microwave Committee. Firstly a proposal to modify the bandplan on the 432MHz band and secondly a proposal to change the existing FM ATV standard.
Many Nordic countries only have access to 432-438MHz and are suffering from increasing levels of QRM from other legal users such as ISM, Short Range Devices and Low Power Devices around 433 ?434MHz. They had proposed that IARU should approve additional terrestrial use of the satellite and ATV segment. This proposal would have risked increased QRM to 70cms ATV activity but, after some long debate, was not accepted. It was agreed that the whole 70cm bandplan should be reviewed in advance of the next interim Managers Meeting in 18 months time so we need to follow this subject carefully in the future to ensure our position is not compromised.
The existing FMATV specification was written and accepted in Torremolinos in 1991. At the last Conference in Tel-Aviv in 1996 it was agreed that it needed amendment so that it could be shown to our PTT?s and regulators that we are keen to ensure the most efficient use of our allocations. In a number of mainland European countries there is much pressure to restrict the number of sound sub-carriers on ATV repeaters to reduce the quoted system bandwidth. This requirement needed to be balanced by not preventing the use of multiple sub-carriers where there is sufficient spectrum available. The resulting recommendation has, hopefully, satisfied this need!
|C5 Chairman ? PA0EZ|
FM-ATV standard for IARU Region 1 September 1999
Video Bandwidth 5MHz
Pre-emphasis According to CCIR 405-1
Frequency of colour sub-carrier 4.433618MHz
Maximum instantaneous deviation ± 3.5MHz
Frequency of sound sub-carrier 5.5MHz
Modulation index of sound sub-carrier 0.07
Signal bandwidth at ?40dBc 12 MHz
Signal bandwidth at ?50dBc 18 MHz
A 5MHz low pass filter shall limit the video. In order to maintain the maximum deviation, the baseband amplitude must be amplitude limited after pre-emphasis but before the 5MHz low pass filter. The carrier frequency shall be maintained independent of the image content
Note: The above specification shall be adhered to on all bands from 1.3GHz to 10GHz inclusive, unless particular National allocations allow systems having a greater overall bandwidth.
This new specification will NOT affect the operation of our ATV repeaters in the UK as we are fortunate on 23cms to have 25MHz than any other country and we do not, for the moment, need to apply these constraints on 10GHz. It does however show the sort of pressures that continue to build up on the use of microwave spectrum. As an aside, it was announced at Shuttleworth, the Radio Communications Agency will shortly be circulating to all Repeater Keepers, for their comment, a draft of a new specification for repeaters. This will, for the first time, specify only a spectrum "mask" and therefore allow more than one sub-carrier.
Finally it was also agreed that the IARU ATV Contest should be organised by UBA (Belgium) in 2000, REF (France) in 2001 and RSGB (BATC) in 2002.
If any members wish a fuller report, I would be happy to provide additional details. Please contact me via email at .