A 2.4 GHz band direct sequence (DS) spread spectrum (SS) radio frequency modem with a wide bandwidth of 26 MHz in half-duplex system has been newly developed using the small size (832 mm) and highly-efficient (-57 dBm) elastic type of surface acoustic wave (SAW) convolver. The size of SS modem is 905011 mm and the weight is 75 g. The power consumption of SS modem is 1.5 W and data rate is 206 kbps with 63 chips of PN code. Electrical characteristics measurements were made to evaluate the SS modem performance.