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 _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
