The share price recovery of Vislink was stopped in its tracks on Tuesday when secure communications specialist said first quarter orders were down 21% at constant exchange rates on last year's first quarter levels.Headline revenues in the first quarter rose 0.6%, while underlying revenues, which are calculated using constant exchange rates and which exclude revenue associated with the 2GHz US spectrum relocation programme, were up 14.2%.The group's order book at the end of the quarter was valued at £34.6m, up slightly from £34.1m at the end of 2008.The group said that customer ordering patterns are becoming less predictable and this, together with the costs associated with its recent restructuring, mean the full-year results will be more weighted to the second half of the year.The group said it trading in line with expectations.