I use Waterlinked systems in several setups.
Separate GPS compass for position and heading is recommended.
WL System works 360 degrees around the boat with correct receiver placement, ie free “sight” from all receivers to the transducer on ROV.
I would not go for the WL antenna, but separate receivers.
For each receiver I have a pipe mounted on the boats, some boats permanent, some temporary.
The pipes are 20mm dia so the receivers is telescopic inside pipe.
Apart from sheltered mounting and easy deployment, you also get more distance in the LBL polygon, giving more precision.
I use one receiver in the bow, and one on each aft corner = 3 receivers.