Home |
Search |
Today's Posts |
#9
|
|||
|
|||
Revisiting the Power Explanation
On Mar 21, 1:32 pm, Dan Bloomquist wrote:
Belief has nothing to do with it. Observations suffice. If you have any doubt that EM radiation can be reflected, just look in a mirror. Did you need to 'believe' you saw your reflection to confirm your observation? I have yet to question the reflection of EM radiation, just the existence of "reverse power" in transmission lines. Red Herring. There is no 'failure' in the accounting of reflected power. The observations and numbers work out quite nicely. A simple example that I can never make add up is a 50 Watt generator with a 50 ohm output impedance, driving a 50 ohm line which is open at the end. Using the "reverse power" explanation, 50 W of "forward power" from the generator is reflected at the open end, providing 50 W of "reverse power". Since the generator is matched to the line there is no reflection when this "reverse power" reaches the generator so it disappears into the generator. If this is truly power, it must go somewhere else, be dissipated, transformed into some other form or stored (based on the conservation of energy principle). Where did it go? Most correspondents agree that what happens depends on the design of generator; dissipation either increases, decreases or stays the same (compared to when the line was terminated in 50 Ohms and the power going down the line is dissipated in the termination). This does not make an easy explanation for where that supposedly real power goes. Of course, if it is not real power, then there is no issue, which leads one back to looking for explanations other than "reverse power". ....Keith |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
The power explanation | Antenna | |||
again a few words of explanation | General | |||
again a few words of explanation | Policy | |||
Explanation wanted | Antenna | |||
New ham needing explanation on radios | General |