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KF5JRV > TECH 01.01.17 15:24l 25 Lines 1570 Bytes #-3187 (0) @ WW
BID : 7970_KF5JRV
Read: DK3UZ GUEST DF7EAV OE7FMI
Subj: Cat's Whisker
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KF5JRV
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While Fleming's valve was a great stride forward it would take some years before thermionic technology was fully adopted. One o
f the reasons for this is that it was expensive to manufacture and to run. It could only be powered by batteries when used as a
radio detector and batteries did not last for long because of the power required by the filament. Batteries were also very exp
ensive as they had not been developed as much as they have been today.
Around this time work on other types of detectors started to be undertaken and it resulted in what was later known as the cat's
whisker. It consisted of a crystal of a material such as galena with a small springy piece of wire brought up against it. The
detector was constructed to that the wire contact could be moved to different points on the crystal, and thereby obtain the bes
t point for rectifying the signal and the best detection.
These detectors soon gained the name cat's whiskers as a result of their construction. They were never very reliable and the wh
isker needed to be moved periodically to enable it to detect the signal properly. However they were very much cheaper than valv
es and gained widespread acceptance.
73 Scott KF5JRV
KF5JRV.#NWAR.AR.USA.NA
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