Jeff, I have plenty of text books here, oh well. All refer to impedance as Z and Z=R+jX or Z = magnitude and phase angle. A 500 Ohm resistor has an impedance of 500 Ohms or 500+j0 or 500 0 deg phase.
I think in Jesse's and my last posting you might see about the low and high freq differences in coax. Maybe not. Oh well. Good discussion. 73, ron, n9ee/r >From: Jeff DePolo <[EMAIL PROTECTED]> >Date: 2007/09/02 Sun PM 12:12:51 CDT >To: [email protected] >Subject: RE: RE: RE: RE: RE: RE: RE: Re: Re: RE: [Repeater-Builder] Re: >Duplexers > >> Impedance refers to both R and X, resistance and reactance. Impedance >affects all current flow, DC and AC. X affects AC only. > >Impedance is specific to AC. There's no such thing as impedance at DC, only >resistance. Look up in the definition of impedance in any engineering text >and you'll find that it only applies to AC. > >A cable's characteristic impedance is determined by the ratio of E to I when >there are no reflections on the line. Reflections can only exist when the >current being carried is varying, i.e. an AC waveform. > >A coaxial cable that has a 75 ohm characteristic impedance will conduct >steady-state DC at any E to I ratio, and will do so without reflection. The >cable does not perform any transformation regardless of the load, unlike the >AC case. > >> No a coax will not function the same at 5 Hz as it does at 2 meters. > >Why not? > >> Evidently you have not had the previledge of working with >> equipment or engineers that allows one to look at some of >> these issues. > >Oh, I think have... > --- Jeff > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
