Description

Some would say a crystal-based IF filter is the very heart and soul of a good SSB rig. There's no doubt that a clean, ripple-free and narrow-skirted "xtal" filter is essential for excellent performance, especially in a receiver. They are, however, among the most difficult builds for a home-brewing amateur to pull off. Among the easiest types, though, are quasi-equiripple designs that do require using xtals closely-matched in resonant frequency (within 50Hz, but the closer the better), but that do not require the careful measurement of "motional parameters" or ESR. More on QER crystal filters can be found in recent (since at least 2011) editions of the ARRL Handbook. The design bandwidth (at 3dB down) of the filters offered here is 2700Hz with a passband ripple of 0.5dB. The insertion loss is approximately 2.3dB depending on the frequency and crystal batch. Kits and fully-assembled & tested filters are available for 4.9152, 9.00, 11.059, or 12.00MHz. Select frequency option when ordering. See the Mostly DIY RF website for technical information and instructions. Fully assembled and tested filters are produced on demand and shipment is within fourteen days of order. For a bare PCB for use with your own components, go to this eBay listing: https://www.ebay.com/itm/325439293152