In comparing system "A" with an antenna gain of 1 to system "B" with an antenna gain of 4, which statement is NOT true?

The statement that System B's signal power per unit area is one-fourth that of System A's signal is not true. In fact, the relationship between antenna gain and signal power per unit area shows that a higher gain translates to greater efficiency in directing the signal. Specifically, an antenna gain of 4 in System B indicates that it can focus the same power over a smaller area compared to System A, which has an antenna gain of 1. As a result, System B actually has a signal power per unit area that is higher, not lower, than System A's signal.

In simple terms, the gain ratio of 4 implies that System B's output is strong enough to improve its effective signal intensity, leading to increased performance in receiving or transmitting signals. Therefore, the incorrect statement fails to recognize that higher antenna gain results in better performance regarding signal strength and efficiency.