Is it possible to see at different point on a Hlog graph where a peak is at what distance along the copper cabling it is?
Try as I might, I honestly do not understand what it is that you are asking. Could you please rephrase the above question?
An HLog graph is a plot of attenuation (in dB) versus frequency (in Hz).
A QLN graph is a plot of signal power (in dB relative to one mW) versus frequency (in Hz).
Your HLog graph is the first that I have ever seen which shows a "sudden" peak. Very peculiar.
Instinctively I would say that it is indicating a defect in the metallic pathway. Being a peak, it indicates a sudden
decrease in attenuation at that particular frequency.
Tone 144 = ((144 x 4.3125) + 2.15625) kHz ~= 623 kHz
Puzzling.