n the view of the dramatic drop in the price of crystals used in color TV sets, they now represent an economical way of building an SSB filter. The circuit shown in the diagram is for a filter with a 6 DB band width of roughly 2.2 KHz. By terminating the input and output with a 1 K Ohms resistor in parallel with an 18 pf trimming capacitor, passband ripple can be tuned down to 2 DB. All crystals used in the circuit are 4.433 MHz. Collect all the six crystals from same manufacture with same serial number.