DESCRIPTION. The DRAKE Model W—4 Wattmeter is a through line wattmeter which accurately measures forward and reverse power. The RF coupler is made removable so that it may be conveniently located at the output of the transmitter. SPECIFICATIONS FREQUENCY COVERAGE. 1.8 - 54 MHz. LINE IMPEDANCE. 50 Ohms resistance. ACCURACY. Wattmeter accuracy is ± (5% of reading + 2 Watts) on 200 Watts scale, and ± (5% of reading + 20 Watts) on 2000 Watt scale throughout the range of 1,8 - 54 MHz. VSWR INSERTION. Insertion of wattmeter in line changes VSWR no more than 1.05:1. POWER CAPABILITY. 2000 Watts RF continuous duty.