A high-power "waffle-iron" or muffler type" waveguide filter provides dissipative attenuation for any power at the second and higher harmonics. Like the klystrons, this filter was developed for the BMEWS radars. The harmonic filter is followed by an antenna tuner in the form of a waveguide magic-T hybrid with motor-driven stubs on two of its four ports. This so-called EH tuner can be adjust to present the transmitter with reflectionless load for any reflection coefficient appearing at the downstairs end of the waveguide. The tuner is followed by 1,500 ft. of WR2100 waveguide that run from the control building to the platform. When considerable EH tuner correction is needed, it is because there are large reflections from the platform-mounted components. Although the tuner eliminates standing waves on the transmitter side, reflections from the platform will, of course, result in standing waves in the 1,500 ft. run of waveguide. But, as is the case in all transmission line situations, if the VSWR on the transmission line is less than about 2:1, the power dissipated by ohmic loss in the line is an acceptably small fraction of the total power.