W7ZOI/K7TAU Spectrum Analyzer Under Construction by N8QOH
Stock 300 Khz Bandpass Filter
Homebrew 300 Khz Bandpass Filter and Screen Shot of Broadcast Band (Span ~2 Mhz)
Homebrew 15 Khz Bandpass Filter and Screen Shot of Broadcast Band (Span ~2 Mhz)
Schematic of Homebrew 15 Khz Bandpass Filter, Costs about $14.00 to build. Warning, the ECS 10.7 Mhz crystal filters have a fair amount of ripple in the pass band. There are better filter modules that are available surplus at hamfests. The W7ZOI web page has a hint telling which caps to change in the 300 Khz bandpass filter to move it to 10.7 Mhz. If other 10.7 Mhz monolithic crystal filters are used be sure that the stop bandwidth is sufficient...