On 7/3/2012 8:01 AM, Lee K7TJR wrote:
> I do not believe we get
> all the information we need as radio guys just from the data sheets. It
> has been the collective wisdom of many including the posters here and
> mentors we have worked with and suppliers we have trusted that have
> in the long run provided the information we as radio guys really need in
> ferrite.
Exactly right, Lee, and that's true of MANY technical products, and
Tom's comments are exactly right too. This is a FAILURE by the companies
involved -- they SHOULD provide the data that Fair-Rite provides, plus
the sort of data that I have provided, and it is to their benefit to do
so because it sells more product. Since I've worked in pro audio for so
long and serve on the AES Standards Committee, I'm most familiar with
that industry. The problem there is that published information is
totally driven and controlled by Marketing, and few, if any, of those
people have even the slightest technical education.
Back in the days when Al Kahn, K4FW, owned EV, they had the best
technical data sheets in the industry, and competing companies gradually
followed suit. Things went downhill in the decades after he sold it to a
conglomerate (and used the money to start Ten Tec across the street from
the EV factory). Now, most well known brands are owned by conglomerates,
and engineers have little if any control of anything related to
published data.
Fair-Rite's excellent published catalog mostly likely reflects the
original owners of the company, who sold it to a conglomerate and
retired sometime after 2005. It is by far, the best I've seen for any
technical product other than those published by some of the major tube
and semiconductor manufacturers several decades ago. Thankfully, current
management has maintained that high standard and even expanded upon it
-- after I published my work, they added data for 2 and 3 turns through
their cores designed for suppression.
Another fundamental problem is that the excellent engineering books on
ferrites published between the 50s and 70s are essentially lost -- long
out of print and hard to find even in the best engineering libraries.
Some of what I've learned and published was well known in the 50s, but
it died with the retirement of that generation of engineers. FWIW -- I
heard NOTHING in my EE courses (finished in 1964) about ferrites, even
though I took as much communications stuff as I could.
All of which is why I've tried to publish as much as I have learned
about both the fundamental circuit concepts involving ferrites and their
practical applications. That's why I've gone to the extent of developing
the equivalent circuits and relating them both to physical
characteristics and published data.
73, Jim K9YC
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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