I'm skeptical that the shown modifications lead to the claimed performance differences. Those leaded capacitors have no effect above 1MHz because their perform

I'm skeptical that the shown modifications lead to the claimed performance differences. Those leaded capacitors have no effect above 1MHz because their performance is dominated by the inductance of their package. Cable modems operate between 5MHz and 200MHz, where all power supply transients will be served by those little ceramic surface-mount caps the author bypassed with leaded tantalums. Above about 1GHz even those are useless and the power supply decoupling is achieved by the capacitance between the copper planes of the circuit board. So it kinda looks like racing stripes on a Geo to me. The claimed improvements could be due to almost anything including unplugging the coax and plugging it back in differently, atmospheric conditions, time of day, etc.