The Ten-Tec Scout was my first ham rig.    What a thrill it was to make a contact with McMurdo Station, Antarctica using 50 Watts and a wire antenna!

The receiver has a crystal IF filter at 6.144 MHz with a varactor variable bandwidth from 500 to 2500  Hz.    Known as the Jones filter, it was designed and patented by retired Ten-Tec CTO, Lee Jones, W4CW.    The slides below show a simulation for it.