[Amps] SWR and amplifiers

[Bill Turner]

There is something I don't completely understand about the effect of
SWR on an amplifier. Perhaps someone here can clear it up?

Let's say my SWR meter indicates 1000 watts forward and 100 watts
reflected. 

1. Does this mean the actual radiated power from the antenna is 900
watts?

2. How much power is the amp actually putting out - 1000 watts or just
900? 

2. If the answer to #2 is only 900, why does the SWR meter indicate
1000? Is that a false reading caused by the actual 900 added to the
100 reflected? If so, why does reflected and actual power add to
produce a false reading?

After 60 years in ham radio I suppose I should know this stuff, buy I
must have been absent that day.  :-)

All comments appreciated. 

73, Bill W6WRT