"Roy Lewallen" wrote in message
...
The average value of a signal is its DC value. To receive and reproduce
a signal with a non-zero DC component means that your antenna, as well
as your receiver, has to have response to DC. To generate such a signal
would require a static electric and/or magnetic field, which can't
propagate. So it's not possible for a signal you're receiving to have a
non-zero average value.

sure it is. and while the 'static' field itself doesn't propagate the
leading edge of a step from 0 to some 'static' value can propagate and if
you measure as it passes you will see the received signal go from 0 to the
static value and then stay there.