Scarce YAESU MTU-80/40 RF uTUNING UNIT-B. External unit adapts to the FT-5000 / FT-2000/ FT-950 series transceiver. complete with cables and instruction manual. CURRENT HRO PRICE: $574.99. My price: $349.99 plus shipping, cash, check, or MO. Data below is from the YAESU website:
On the lower Amateur bands, the signal voltages impinging on a receiver can create noise and intermodulation effects that can cover up weak signals you're trying to pull through. Three modules (MTU-160, MTU-80/40, and MTU-30/20) are available – these modules may be connected externally with no internal modification required!
The RF µ-Tuning filters utilize a stack of large 1.1" Ni-Zn Ferrite cores, driven through a silver-plated coil assembly by a precision stepper motor. The resulting high Q (typically over 300) provides a very steep resonance peak near your operating frequency. (On the 160 m band, typically -3DB@?12 kHz, -30DB@?450 kHz.) And the 3rd order Intercept Point (IP3) is increased by 4 dB with the RF µ-Tuning system.
The ferrite cores utilized in the RF µ-Tune filters are driven by a high-resolution, high torque stepper motor (4-phase unipolar motor/2-phase magnetization system) with angular resolution of 1.8deg. The synchro belt drive has an estimated lifetime of more than 10,000 hours of actual operation. For 160-meter operation, the ferrite core diameter is a full 2.2"! The RF µ-Tune system tracks your operating frequency, although you can chose to manually skew the frequency response when special interference conditions require it.
If you turn the RF µ-Tune system off when leaving your frequency or QSYing to other bands, the RF µ-Tune system will be re-centering the RF µ-Tune filter on your current operating frequency when the RF µ-Tune is re-engaged.