John,

At 09:57 AM 4/3/2004 +1000, Harry Lemmens  wrote:
>On some prox antenna stuff I did years ago, I found that the series
>tuning/coupling capacitor was the critical element. If I used a common "garden
>variety" SMD capacitor, there was about 70 volts across the coil. When I changed
>to a "Low dissipation" (IE: High "q" capacitor) the voltage on the coil went to
>about 220 volts. (9 times the original power) and the circuit reading/writing
>distance improved by about 4 times. So don't always blame the antenna inductance
>of you are having trouble ... 


I cannot reiterate Harry's point strongly enough, especially if the frequency is high. 
 We find high-quality, high-frequency ceramic capacitors absolutely essential in our 
line of work.
Without them you will suffer high losses, weird resonances, and low Q's in circuits 
sensitive to this sort of thing.  We mostly use American Technical Ceramics (ATC) 
capacitors (or other premium manufacturers) in these applications.  Don't forget that 
these are some of the best high-speed decoupling caps on the planet.


Frank Gilley
Dell-Star Technologies
(918) 838-1973 Phone
(918) 838-8814 Fax
[EMAIL PROTECTED]
http://www.dellstar.com 



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