[G0HZU_JMR]

One other thing is that it isn't clear how it is being tested because the photo shows a run of coax going up to a counter. I looked up the circuit for that PW counter and it looks like it has a BJT configured as a common emitter amplifier on the HF port. This will probably have a fairly capacitive input impedance up at HF/VHF.

This will limit the HF performance because there is also the capacitance of the unterminated coax. This is all being driven by a 2N2222A BJT with a 1k collector resistor at the buffer amplifier output. That will create a lowpass filter. Is the circuit being tested in isolation or in the system with the counter?