If you take RG400 or RG213 or what ever for each piece of coax short the center conductor and shield together on each end. Space the two pieces about 1/8 inch or just tie wrap them together and you have about 200 ohm feeders. Put on a 4:1 current balun and your in business. Make the feed line 1/4 wave long.
Keep The Faith, Jim K9TF/WA9YSD