On Sep 1, 9:52*pm, Owen Duffy wrote:
wrote in news:6f4f9e36-af26-4f1b-9244-383494f77b26
@c58g2000hsc.googlegroups.com:



On Sep 1, 3:25*pm, Cecil Moore wrote:
wrote:
...
Actually, 1000 ohms is pretty liberal. For instance, on
15m, the G5RV coax sees 36+j230 ohms or about 233 ohms.
The balun needs to be 10x that value or 2330 ohms.
--
73, Cecil *http://www.w5dxp.com

Why not 500 ohms, assuming a 50 ohm source and transmission line?

The common mode impedance of the balun acts in the common mode
transmission line (which is mutually coupled to the nominal radiator).

How is the differential mode transmission line characteristic impedance
relevant to the determination of common mode current in the antenna
system scenario described?

Owen

For a balanced transmission line, the characteristic impedance is not
expressed in differential mode terms, it IS common mode so I do
not know why you ask about differential mode characteristic impedance.
I never mentioned it. The characteristic impedance of a ladder line
for example
might be expressed as 600 ohms. That 600 ohms assumes common mode
conduction, as charateristically transmitted in a balanced line,
Differential mode impedance is assumed for un balanced transmission
line conditions.