This NEW never used 525 AM Reference Receiver and Modulation Monitor is specifically designed to give accurate AM readings with Hybrid Digital (IBOC) transmissions. It is menu-driven, with a peak-hold LCD display that shows simultaneous positive and negative modulation, incoming RF level and asynchronous noise. Measurement bandwidth extends to more than 10kHz, but a programmable low-pass audio filter can simulate the response of consumer radios or the effects of transmission bandwidth constraints. It comes with an outdoor large aperture loop antenna. It sports a 75-ohm (F) input specifically intended for the large aperture loop antenna (cable is not included, but up to 100 feet of common RG6 TV coax may be used). There's also a high-level (BNC) input that accepts a direct RF sample from the transmitter between 1V and 7V r.m.s. Its active-balanced (XLR) program audio output delivers +4dBm at 100% modulation. A front-panel headphone jack (1/4-inch TRS) also monitors the demodulated audio.