My specialty is UHF TV. We use bigger lines. 3 1/8 is plenty at 0.64 MHz.

www.eriinc.com/pubs/Catalog07_160-163.pdf

In article ,
Dave wrote:

My specialty is UHF TV. We use bigger lines. 3 1/8 is plenty at 0.64 MHz.

www.eriinc.com/pubs/Catalog07_160-163.pdf

Maybe I don't understand some of the ramifications of power but I do
know that cables and connectors are designed to keep the RF energy in
one TEM mode so conductor spacing is determined by frequency. The space
can't be so large at the frequency of operation that more one than
propagation mode is then possible. That means the line and connector
impedance will change dramatically with small changes in frequency and
power.

The rule here is that the higher the operating frequency the smaller the
conductor spacing has to be so then power will dictate the line diameter
by what would be required for a low loss conductor size.

--
Telamon
Ventura, California

Telamon wrote:
In article ,
Dave wrote:

My specialty is UHF TV. We use bigger lines. 3 1/8 is plenty at 0.64 MHz.

www.eriinc.com/pubs/Catalog07_160-163.pdf

Maybe I don't understand some of the ramifications of power but I do
know that cables and connectors are designed to keep the RF energy in
one TEM mode so conductor spacing is determined by frequency. The space
can't be so large at the frequency of operation that more one than
propagation mode is then possible. That means the line and connector
impedance will change dramatically with small changes in frequency and
power.

The rule here is that the higher the operating frequency the smaller the
conductor spacing has to be so then power will dictate the line diameter
by what would be required for a low loss conductor size.


You're confusing coaxial lines with waveguide. With coax, higher
frequencies require bigger cable; skin effect.