First-half profits were much lower than the previous year's at walkie-talkie maker Sepura as it invested in new products and routes to market.Adjusted operating profits plunged 83% to €0.6m in the six months to September 27th, even though revenues rose 6% to €46m. FTSE Small Cap-listed Sepura's revenues were boosted by recently acquired fellow terrestrial trunked radio (TETRA) manufacturer 3T, rebranded as Sepura Systems, and the even more recent addition of application developer Portalify.Chief Executive Officer Gordon Watling said: "The record first-half revenues we have announced today are a direct result of investing in products and markets we have previously identified as offering long-term growth potential."Management were encouraged by the start to the year, particularly continued strong operating cash generation and record System's order book, and have increased investment to broaden the product range, at the expense of short-term profits. To placate investors and express their confidence about the company's ability to meet market expectations for the full year, the board made a 15% increase in the interim dividend to 0.59p per share.Shares in Sepura were down 8.2% to 129.5p at 14:17 on Wednesday.OH