As to the radio issue, there are so many factors that affect propagation: type of antenna, loss of signal from too small wiring, loss of signal from degradation of the wire or coating due to age, position of the antenna (if it is tilted).
On another subject, I was amazed at how many competitors had AIS transponders. The starting line on my plotter was a minefield of triangles pointing every which way. I was very happy to have my transponder on and the receiver going while crossing the fogged in bay. It paid for itself in avoiding the shipping traffic. It was the first time I was sad that I removed my radar as the non AIS boats kept popping out of the fog (fortunately we were all heading toward the start so closing speeds weren’t bad.