On 6/12/11 7:57 PM, Dave Brown wrote:
For a given OD the centre conductor will be SMALLER diameter for 75 ohm
cable wrpt 50 ohm cable.
Google for the whole minimum loss/highest power xfer capability etc
issue as regards coax cable diameter and impedance. All std textbook
stuff. Or used to be!
DaveB, NZ
http://www.microwaves101.com/encyclopedia/why50ohms.cfm
lowest loss is at 77 ohms for air dielectric
Other tricky aspects in real systems..
Higher Z might have lower loss because IR losses dominate, and higher Z
is lower current (for the same power), hence the popularity of open wire
ladder line.
If the line is short (compared to a wavelength.. probably not an issue
for GPS, except in jumpers internal to equipment), loss due to mismatch
gets trickier (because you don't have a complete cycle)
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