Installing a 4 G on my flybridge behind the aft rail on a pole to extend over the biminni on the starboard side.
Two questions :
1. Is it okay to install there or on the centerline ?
2. I have two VHF antennas mounted on either side of the flybridge toward the front of the flybrige. Will the two antennas significantly block the radar signal ?
Depending on the beam of your vessel, it's probably not even noticeable if your radar is a few feet off center. More of an issue if your GPS sensor is far abeam from your radar, so that you have a parallax between them if you are doing overlay, even then at practical distances not likely an issue.
VHF antenna are classically narrow whips, and will not materially block a Radar signal from a rotating antenna. Note that Sailboats have similar sized standing rigging and larger aluminum masts and still get good signals around them.