It's actually a Dish Network triplexer, I have the dipole on the first spot and I've tried the other antenna on the 2nd and third spot.
http://pimages.solidsignal.com/ES175284_1_zoom.bmp
I also tries a Radio Shack Splitter combiner with less luck. Radio Shack also has a UHF/VHS diplexer that I was going to try. Good to see Radio Shack back in business.
http://comingsoon.radioshack.com/vhf...l#.VYV_AmRViko