>From: Eric Lemmon <[EMAIL PROTECTED]> >Date: 2007/09/02 Sun AM 09:47:30 CDT >To: [email protected] >Subject: [Repeater-Builder] Low-Frequency Cutoff (Was: Duplexers)
> >I think we're talking apples and oranges here. A hollow waveguide of a >specific dimension does have a low-frequency cutoff point, below which a >wave cannot propagate through its length. But, a coaxial cable is not a >waveguide, and it does not have a low-frequency cutoff. > >73, Eric Lemmon WB6FLY > > >-----Original Message----- >From: [email protected] >[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo >Sent: Sunday, September 02, 2007 7:01 AM >To: [email protected] >Subject: RE: RE: RE: RE: RE: RE: Re: Re: RE: [Repeater-Builder] Re: >Duplexers > ><major snip> > >> There is a point at which it starts to >> propergate and does look like 75 Ohms. I think you might >> understand this. > >I'm not trying to rake you over the coals Ron, but I *am* trying to prove a >point: there is no low-frequency cutoff for coaxial cable, period. You may >experience (or even measure) behavior at very low frequencies when the cable >is a small fraction of an electrical wavelength that might make you want to >think otherwise, but it's not due to transmission line theory, math, or >physics breaking down at some low-frequency cutoff. > >--- Jeff > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
