Steve Thompson wrote:
> I thought 35ohm was max power rating, 75ohm was minimum loss?
> Hence 75ohms being the standard for CATV.
Actually, with everything being the same the lowest loss is from the highest
impedance possible
for the form factor, the highest power handling capacity is from the lowest
impedance.
75 Ohms coax has lowest loss because for a given power rating because it has
the highest Voltage and
the lowest current which fits into the I*R = power loss formula.
With 250 to 1,000 Ohms surge impedance the form factor "open wire feed line"
(and shielded open
wire feed line called "waveguide") posses the lowest loss and it really makes a
difference when
there are reflections, as in when you are operating off of resonance, such as
the other end of the band.
--
73 Ron KA4INM - All E-mail sent to this address shall linger in the Google
cloud forever!
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