Great duplexer info on that site. Their focus seems ?to be on the loop in the top of the duplexer. I still have not found info on what a TX/RX loop looks like.
As to going vertical, our antenna is on a building parapet, no way to put one above it.
As to the length being the same as a 440 MHz?can, ours are 800 MHz so without an actual measurement I still don't know where to start.
Thanks again for the support guys, keep the comments coming.
Rex AJ4GC