Step. 11
Bird 43 power meter readings following the readjustment procedure now
indicate 130w forward and 29.5w reflected, indicating 100.5w
delivered to the mismatched load.

Points in response:
1. The cost of the variation in usage of the term Step now comes home
to roost. This step is obviously simple reporting. However, it is
reporting out of sequence, which is the purpose of offering Steps so
that this can be avoided.
2. It also reveals the problems of precision offered where impedances
are reported to 2 decimal places (exceeding the accuracy of
equipment). Formerly, Maximum Available Power was explicitly defined
(to one decimal place) as 100W, and now we find 100.5W applied to the
newly matched load. The laws of precise reporting would suggest the
earlier Maximum Available Power should have been specified at 100.0W
(tenths of W precision); or consistent with its earlier 1% precision
that this new reading should be offered as 101W (with appropriate
promotion of the 0.5W).
3. I would point out that the Bird 43 Power Meter's accuracy is 5% of
full scale and that to this point no specification has been offered as
to what actual equipment is being used as there are seven possible
plug-ins available (where only three would be sensibly chosen here).
This gives rise to the author conferring upon the reviewer the power
to choose for him. I will arbitrarily infer from the information
provided that two plug-ins are used: 100W and 250W. The 100W would be
selected for the first power reading offered in Step 1 as this would
give the greatest accuracy to that cardinal point. The 250W element
for the 130W reading in Step 11. I presume that the 100W element
would be used for the reverse power readings, as that would be the
greatest advantage; unless, of course, the 50W element was available
(this is the hazard of incomplete reporting).
4. A 29.5W reading is both an interpolation (there are no half Watt
gradations), and subject to error. The proper reporting would allow
for the interpolation but cite it as 29.5W ±5W (or nearly 17% of
reading).
5. A more substantial ±25W error inhabits the 130W reading due to the
use of the 250W element. The proper reporting would allow for the
interpolation but cite it as 130W ±25W (or nearly 19% of reading).
Given that these are two, separate measurements, we have to render the
delivered power as:
(155W .. 105W) + (-34.5W .. -24.5W)
where the optimistic combination of all inaccuracies offer a spread of
delivered power:
120.5W .. 80.5W
This is a huge variation of ±20W around what had been presumed to
represent the Maximum Available Power of 100W (which, in itself could
only have been reported as 95W .. 105W).
6. For the reader, there is a object lesson to be learned here in
regard to RF power measurement accuracy where none is required (as I
pointed out, the introduction of Maximum Available Power is an
unnecessary elaboration to the subordinate thesis). That is, the
greatest usage of the Bird (or any indicating instrument) would be
found in returning the system to a cardinal reading point on its
scale. This would collapse the nearly 20% error to less than one-tenth
that value.... If it mattered at all (it doesn't).

73's
Richard Clark, KB7QHC