The Model QR-1 is a broadband, dual polarized quad-ridged horn. It operates from 700 MHz to 6 GHz. It is compatible with all models of Howland Wireless test Labs with the exception of the Model 2100.
The Model QR-3 is similar to the Model QR-1 but is designed to operate down to 400MHz. It can be used as the measurement antenna in the Model 4100 and Model 4800 Wireless Test Labs.
The Model QR-4 is very similar to the QR-1 but it has been optimized for small size and light weight. The return loss is slightly higher than the QR-1 and its pattern is not quite as directive. However, it achieves performance that is very close to that of the Model QR-1 in a much smaller package. It is compatible with all models of Howland Wireless Test Labs.