[G0HZU_JMR]

Looking closer at the HF input port of the PW Robin circuit it might be the case that this lowish input impedance needs to be driven by a fairly low impedance at the buffer end of the coax. This assumes a typical coax run of maybe 60cm feeding into the counter. The input impedance of the coax feeding into the counter could easily be the equivalent of 100R in parallel with 100pF by 30MHz. When this heavy loading gets presented to the collector of the output BJT of the existing buffer circuit I think this will spoil the system gain up at 30MHz.