Dl 614 , wireless connection problems

Hi, On a similar model, the advertised range is anywhere from 50-100 meters outdoor or open air. Inside the house or within the office, the walls, doors, drapes, furnitures etc obstruct the signal and brings down the range to less than half. What we have tried to improve the signal range: 1. Install the AP/Router high up not just on top of a closet or cabinet but really high, about a foot from the ceiling; 2. Approximate the very center of the various locations of the laptops and install the AP/Router there; 3. Disabled and did not use security WEP, WPA but turn MAC Filter on; 4. Use an external hi-gain omni antenna; 5. Install a second similar unit at the farthest coverage and run it as a repeater; 6. Replace the AP/Router with the new N type (which again claimed to be 4X wider and 12X faster) which made us go back to step 1. It's a love/hate experience and we ended installing more repeaters. But it works. Hope this give you an idea or two (but hopefully not the frustration nor the headache). Post back how things worked out your end. Cheers