Harky

Hello, First post here, i am looking for some help with Zxtech IP Cameras. This setup is on a farm so it is a large open area with the cameras on the sheds which are around the farm house. I have 3 of the 4 cameras up, but the signal from the router (BT Home Hub 3) that i have placed in the loft does not have very good range, so the signal keeps on dropping resulting in no picture on the monitor from time to time. Running cables is not relay an option because of the distance and limited routes to take, i have tried using a wireless extender but there is to much lag when viewing on the monitor. I was thinking to have an external router or some sort of aerial that would give me better signal to and from the cameras and place it on the chimney stack on the house. Could someone please recommend something to achieve this setup? Help will be appreciated. Link to cameras: http://www.ebay.co.uk/itm/Zxtech-4-2-Mega-Pixel-1080P-Camera-IP-Camera-Cloud-Recorder-Wireless-CCTV-System/171932925805?_trksid=p2047675.c100009.m1982&_trkparms=aid%3D888007%26algo%3DDISC.MBE%26ao%3D1%26asc%3D20140328180637%26meid%3De5e194a91d7b4a819ad262ab9c15d11a%26pid%3D100009%26rk%3D1%26rkt%3D1%26sd%3D191690776669