Good ol' 9913 uses the same Belden "DuoBond II" shield like they use in
RG6-type cables. It is aluminum foil/mylar with a relatively loose (90%
coverage) tinned copper braid over it.
LMR-type cable uses the same shield construction as 9913.
The primary difference between 9913 and LMR-series cables is the dielectric.
9913 uses the "semi hollow" dielectric comprised of a "tube" of solid
dielectric with a spiral spacer between it and the center conductor. This
reduces the loss (and increases the Vf) as compared to having a solid
dielectric. LMR, on the other hand, uses a low-density foam dielectric, no
spacer or air. It's easy for 9913 to turn into a water hose. I've had this
happen at more than one site; scratch your head and wonder how the top of
the cabinet is dry but the floor inside the cabinet is wet...
--- Jeff
> -----Original Message-----
> From: [email protected]
> [mailto:[EMAIL PROTECTED] On Behalf Of skipp025
> Sent: Thursday, June 07, 2007 3:13 PM
> To: [email protected]
> Subject: [Repeater-Builder] Re: Which coax cables to use with
> repeaters?
>
> Hi Jeff,
>
> > "Jeff DePolo" <[EMAIL PROTECTED]> wrote:
> > I think this is, or should be, a repeater-builder FAQ.
> >
> > Foil+braid cables like 9913, LMR-series, etc. should generally
> > NOT be used in duplex environments.
>
> What really fans the "LMR-400 is ok" fire... is the number of Wifi
> people using it. They don't normally report the duplex operation
> problems because the wifi stuff is normally a half duplex operation.
>
>
> > Although a few may report results to the contrary,
> > braid-over-foil cables produce noise due to the dissimilar
> > metal contact, particularly as the cable ages/weathers. As
> > such, they should be avoided.
>
> Is 9913 a dissmilar metal coax? I've seen some versions with a
> thin copper foil... but not aluminum.
>
> cheers,
> skipp
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
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