The errata list is a list of errors and their corrections that were found after the product was released. If the error was corrected in a later version or reprint the date of the correction will be displayed in the column titled "Date Corrected".
The following errata were submitted by our customers and approved as valid errors by the author or editor.
Color key: Serious technical mistake Minor technical mistake Language or formatting error Typo Question Note Update
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Page 77
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In section 6.2.3 of Rob Flickinger's book, he calculates the total system gain as
below:
"Next, add up all of your gains (radios + antennas + amplifiers) and subtract your
losses (cable length, connectors, lightning arrestors, and miscellaneous other
losses). Let's assume you are using Orinoco Silver cards (15dBm), no amplifiers, with
a 12dBi sector on one side, and a 15dBi yagi on the other. We'll assume you're using
one meter of LMR-400 and a lightning arrestor on each side, allowing 0.25dB loss for
each connector, and 1dB for each pigtail. Since all of the units are in dB, we can
use simple addition and subtraction:
radio - pigtail - arrestor - connector - cable - connector + antenna
Site A: 15 - 1 - 1.25 - 0.25 - 0.22 - 0.25 + 12 = 24.03
Site B: 15 - 1 - 1.25 - 0.25 - 0.22 - 0.25 + 15 = 27.03
A + B = 51.06 total gain "
It is incorrect to add in the radio transmit power twice. If you are
calculating total path gain, then the power gain figure of the receiving
radio is immaterial.
The correct calculation is below:
radio - pigtail - arrestor - connector - cable - connector + antenna
Site A: 15 - 1 - 1.25 - 0.25 - 0.22 - 0.25 + 12 = 24.03
- pigtail - arrestor - connector - cable - connector + antenna
Site B: - 1 - 1.25 - 0.25 - 0.22 - 0.25 + 15 = 12.03
A + B = 36.06 total gain
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