Passive Preselector with high dynamic range! It improves the performance of nearly any HF or shortwave receiver/transceiver. It vastly improves the most expensive receivers. Especially helpful to those with broadband front-ends that are prone to overload. Protects your sensitive receiver input from damage (including switching diodes and attenuator resistors) caused by very strong signals from multi-transmitter, multi-band operation -- contests, field day, nearby hams, CBers, TV/FM/AM stations.
It eliminates phantom signals by suppressing strong out-of-band signals that cause intermod, blocking and cross modulation. Completely eliminates second order intermod problems caused by strong out-of-band shortwave broadcast signals mixing and producing unwanted in band signals.
Has narrow bandwidth, excellent stopband attenuation, low loss, constant bandwidth and gain over each band. Excellent attenuation in adjacent contest bands.
The entire 1.6 to 33 MHz HF band is covered in five overlapping bands. An RF sense transmit/receiver switch with adjustable time delay automatically bypasses your MFJ-1048 when you transmit. Also has PTT line T/R switching. Plugs between antenna and transceiver. Fully shielded metal enclosure. Tough black finish.