[TenTec] OT: SWR & Coax

shristov shristov at ptt.rs
Mon Jul 7 04:57:21 EDT 2008


Basic facts of physics are as follows.

1. Whenever an AC current flows, there is radiation.
    There are no exceptions. Also, there are no additional conditions.
    All that is needed is an AC current flowing.

2. The only way to "prevent" radiation is to counteract it by a radiation
    from another AC current of the same magnitude and opposite phase,
    flowing in a nearby conductor.
    This is how transmission lines work, both "coaxial" and "open".

3. If the cancellation mentioned above is not complete (inequal magnitude,
    inexact phase, separation too large) the transmission line will radiate.
    This is what happens with "unbalanced" lines, carrying "common mode"
    currents in addition to normal "differential mode" currents.

4. This has nothing to do with SWR.
    SWR is a completely different phenomenon.
    It neither enables nor prevents radiation.


73,

Sinisa  YT1NT, VE3EA




More information about the TenTec mailing list