Broadcasting and surveillance equipment specialist Vislink accompanied a solid set of half year results with news it was buying Amplifier Technology for up to 4m pounds. Vislink said the deal would enhance it product range in homeland security and defence markets.Amplifier Technology, based in Yate near Bristol, makes amplifiers and jammers for the defence and surveillance market.The announcement sent shares soaring 13% to 42.5p by 14:26 on Thursday.Executive Chairman John Hawkins said the acquisition would add to Vislink's ability "to equip and protect the modern soldier."The deal was announced alongside figures showing pre-tax profits rose to £1.4m in the first half from £0.7m after orders climbed to £33.6m from £25.4m driven by increased demand from both the broadcast and surveillance markets.Hawkins added: "We remain on track for our plan to grow the business to £80m and £8m adjusted operating profit by the end of FY 2014, and we intend to support this by way of a number of 'bolt-on' acquisitions."The company is not paying an interim dividend. TB