31 Mar
2005
31 Mar
'05
2:53 p.m.
>>>> "Jochen" == Jochen Kunz
<jkunz at unixag-kl.fh-kl.de> writes:
Jochen> On Thu, 31 Mar 2005 14:38:07 -0600 Tom Peters
Jochen> <tpeters at mixcom.com> wrote:
> I'm still looking for specs on thicknet
cable-- I know the
> characteristic impedance is 50 ohms, but if I knew the velocity
> factor and losses at VHF (144 - 148 mhz) and UHF (430 - 450 MHz) I
> could use the stuff for my amateur radio hobby. As it is, it's
> gathering dust.
Jochen> AFAIK thick Ethernet cable is more or less RG213.
Typical
Jochen> values are 8 dB / 100 m attenuation at 150 MHz and 15 dB /
Jochen> 100 m at 450 MHz and a velocity factor of 0.66.
The Ethernet spec says 0.77, not 0.66 -- foam dielectric, after all.
(0.66 is the usual value for solid polyethylene dielectric.)
It also says max of 8.5 dB attenuation per 500 meters (i.e., 1.3
dB/100m) at 10 MHz; there isn't a VHF spec. Then again, it's high
grade cable, I'd expect it to do well.
paul