atisti- cal (non-Gaussian) nature of the decision quantities, Wx is the detection channel bandwidth, and Tx is the detection integration inteval. A wideband detector requires Wx = Wss (total hop bandwidth) and Tx = TM (total mes- sage duration) while, for the PB-FBC, Wx =Wh (hop pulse bandwidth) and Tx x = Th (hop pulse duration). The communicator therefore has three para- Interception Detectors meters which he may change or influence in some fashion to make detec- tion more difficult for the interceptor, namely, his transmitter power, which directly affects S/N Wx, and Tx For the wideband detector, it is clear that restructuring the signal per-hop bandwidth within a fixed total bandwidth of Wss (assumed to be at its max- imum value already due to RF channel allocation regulations) has no impact on wideband detector performance. One option of the communi- cator is to lower his bit or symbol rate by a factor of l < 1. This implies that his transmitter power may also be lowered by this same 1 factor (ignor- ing, for the present, the likely increase in non-coherent combining loss in the receiver), meaning that the interceptor's received SIN is also reduced by 1. Now, since Tx = TM is increased by 1/1 (the number of bits per mes- sage is fixed), the net effective SIN loss to the interceptor is proportional to VA, as can be seen by referring to (1.24). It is clear that not quite all of this advantage will be gained if the communicator's non-coherent combin- ing losses are accounted for, but some increase in covertness can be expected from this strategy. The other option of the communicator as regards the wideband detector is to time hop the message, i.e., to transmit the bits or hop pulses in a time- pseudorandom and non-continuous fashion. Thus, the message transmitter is pulsed on and off in a sequence known only to the communicator. if the transmission is therefore effectively spread in time from TM to STM, d > 1, the interceptor has no choice but to make his Tx = STM while, at the same time, his average SIN decrea