02-10-2016, 08:08 PM
Twisted pair:
Cat3 is about 60pF per meter, Cat5 less. So 1K (or sounds like it might even be 2K) driving twisted pair seems a bad idea for longer distances. Characteristic impedance might be about 120 ohms. Why were they making it bad by such large resistances and a "not really balanced" connection?
Measuring capacitance of cable can usually be done quite reliably at 1kHz or 10KHz etc, without difficulties of measuring cable inductance.
Cat3 is about 60pF per meter, Cat5 less. So 1K (or sounds like it might even be 2K) driving twisted pair seems a bad idea for longer distances. Characteristic impedance might be about 120 ohms. Why were they making it bad by such large resistances and a "not really balanced" connection?
Measuring capacitance of cable can usually be done quite reliably at 1kHz or 10KHz etc, without difficulties of measuring cable inductance.
