t power jammer is the worst jammer in a Rayleigh fading channel. This is primarily due to the fact that Rayleigh fading has already created the same impact as that of a worst case pulse jammer with a resulting uncoded bit error bound that changes slowly with increasing values of E/NJ Changes in the signal-to-noise ratio caused by a pulse jammer no longer result in large changes in the uncoded bit error probability and the constant power jam- mer turns out to be the worst case. Coding and interleaving still showed dra- matic improvements but this time to overcome the effects of Rayleigh fading. For other fading statistics it is not clear what is the worst pulse jam- mer parameter. Each case would have to be analyzed separately. 1.7 SLOW FADING MULTIPATH CHANNELS In many radio channels signals reflect off the surface of water, buildings, trees, etc., causing multiple signal terms at the receiver. The atmosphere also causes reflections where sometimes the reflected signals are used as the pri- mary means of sending signals from transmitters to receivers. Examples include shortwave ionospheric radio communication at HF (3 MHz to 30 MHz), tropospheric scatter radio communication at UHF (300 MHz to 300 MHz) and SHF (3000 MHz to 30,000 MHz), and ionospheric forward scat- ter radio communication at VHF (30 MHz to 300 MHz). These fading mul- tipath channels are usually modeled as having a randomly time-varying filter together with noise and interference [33]. Examination of the DS/BPSK system in a fading multipath channel begins by defining the DS/BPSK signal in (1.4) with an arbitrary phase term A, i.e., x(t;0)c(t)d(t)V2Scos[wot 0]. (1.158) The simplest multipath example is where thee is an unfaded direct path sig- nal and one reflected path signal. The received signal has the form (1.159) Here a is the reflected signal amplitude term, T is its delay relative to the direct signal, and O is its phase relative to the direct signal. Here x(t) = c(t)s(t) is the DS/BPSK signal with no fading and J(t) is the jamming signal. Sl