rickman wrote:
On 10/27/2014 7:38 PM, gareth wrote:
"gareth" wrote in message
...
Consider 100W at 3.6MHz propagating along some 50 ohm
coax, which terminates suddenly but with 1/4 inch of the central
conductor protruding.


Actually, here is a better example, because it represents the situation
found in many shacks.

Consider 100W at 3.6MHz propagating along some 50 ohm
coax, which terminates suddenly but with 1/4 inch of the central
conductor protruding, and thereby forming a short antenna.

The short antenna, only 1/4 inch long is immediately terminated
by a 50 ohm resistance.

1. How much of the power from the coax is fed into that short antenna
despite
the claimed (by others) impedance mismatch?

2. How much of that power is radiated by that short antenna?

3. If all the power that is fed to the short antenna is radiated, does the
50 ohm resistor dissipate any of it?

4. How much of the power is dissipated in the 50 ohm resistor?

5. How much of the power is reflected back down the coax because
of the impedance mismatch of that (very) short antenna?

You are right. Very little of the power reaching the end of that cable
will be radiated. Most will be reflected back down the cable toward the
source. When you add a 50 ohm termination you will still have very
little radiated. Nearly all of the power will be dissipated in the
resistor.

I think you have a very clear picture of what is happening.

Nope, it just shows he does not understand the concept of impedance
matching.



--
Jim Pennino