These original Kirt's Cogitations™ may be reproduced (no more than
5, please) provided proper credit is given to me, Kirt Blattenberger.
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Cog·i·ta·tion [koj-i-tey'-shun] – noun: Concerted thought or
reflection; meditation; contemplation.
Kirt [kert] – proper noun: RF Cafe webmaster.
Caveat emptor. Now there is a fine Latin phrase that is
oft repeated. Although it is hard to imagine anyone not knowing what
it means, the common translation is, “Let the buyer beware.” The admonition
applies not just to the paying of cash for a product, but also to the
accepting of or assuming that information is accurate as presented.
The universal warning to not believe anything you read on the Internet
is gross overkill, but a healthy dose of skepticism is definitely in
order when researching data that will be used in the critical projects.
Verification is mandatory. Trust but verify.
On rare occasions
while collecting data for inclusion RF Cafe, I have run across websites,
printed material and software that, upon cross-checking, have proven
to be inaccurate. Filter equations are a good example. Without citing
specific names, titles or URLs, I will tell you that there are many
instances of incorrect transfer functions for denormalized transfer
functions – particularly bandpass and bandstop. I have discovered inconsistencies
in college textbooks, websites and even in software. Inductance and
capacitance calculations are another area where with little effort,
one can locate numerous different equations for the same calculation.
These differences I write of are not just due to rounding errors in
constants or multipliers; many times the errors are due to misplaced
parentheses or a plus sign where a minus sign should be. Such little
mistakes can produce results that have the potential to doom a design
attempt if not caught in time. Most publishers, I have to believe, are
very conscientious about cross-checking their work since not only is
their reputation on the line, but they sincerely would never want to
Unfortunately, there are too many websites that
are composed primarily of pages copied directly from other people’s
work. This often leads to the perpetuation of erroneous information.
I have run across many instances of exact copies of RF Cafe web pages
(as well as of other website authors’ work), some so blatant that the
thieves were too lazy (or dumb) to remove the list of keywords that
include “RF Cafe.” Many of my original graphics are replicated on other
websites. To my knowledge, RF Cafe has no unauthorized versions of anyone
else’s material of any sort. Visitors are encouraged to report any suspected
Mea Culpa. That is another familiar Latin
term whose translation is not as well known. It means, “I am culpable.”
Basically, it is an admission of guilt. Here is my mea culpa. Over the
six-year span of RF Cafe’s powerful online existence, there have been
a few instances where visitors have written to notify me of erroneous
data on the website. To the best of my recollection, most of the discrepancies
have been things like misplaced decimal points in tables of data. All
claims of errors are researched and corrected if found to be justified.
Usually the person who notifies me is right, and I appreciate the feedback.
As time permits, I review the pages on RF Cafe to look for undiscovered
problems with text, equations and images. Again, you are encouraged
to report any suspected oversights.
When corrections are made,
I place a notice on the page, as with the “Drill
Sizes – Numbered” page. An example of something other than a misplaced
decimal point is on the “Inverse
Trigonometric Identities” page. Most people are cordial in reporting
the errors. In the case of the Trig Identities error, the reporter pretty
much lambasted me for all the high school students I have probably misguided
due to sloppy proofreading. I will try to do better. Fortunately, the
Mars Climate Orbiter crash in 1999, caused by an incorrect conversion
between English and metric units, predated RF Cafe so I will hereby
absolve myself any responsibility for that misadventure.