Parrothead AIS Antenna Issue

[dsbentley]

I bought a Smart Radio AIS receiver from Capt Jacks and they said I could use a VHF antenna splitter and use the same antenna on my mast head that my VHF radio uses. I called Shakespeare after buying their splitter and they said this would not work as the splitter would stay on the last device to use the antenna and could cause a problem with the VHF radio. Someone told me I could the Smart Radio splitter http://www.milltechmarine.com/images/VHF_splitter.JPG and this will work. What is the difference and will this have any effect on my VHF performance?