E
L E C R A F T
K N B 2
N O I S E B L A N K E R
Assembly and Operating Instructions
Revision D, Aug. 20, 2002. Copyright © 2002, Elecraft; All Rights Reserved
Introduction
The KNB2 noise blanker can be used to suppress most wide-band noise, including that generated by
automobile ignition systems, power lines, and appliances. In many cases, signals that were completely
"buried" in noise will become easy to copy with the blanker turned on.
Various settings are provided to make the noise blanker more versatile. Two blanking pulse widths are
available, as well as two noise threshold settings. These selections are made using the K2's front panel
N B
and
L E V E L
buttons, respectively. Refer to
Using The Noise Blanker
for details.
The KNB2 plugs directly into the K2's RF board with no additional wiring. It is controlled by the main
processor on the control board via the K2's "AuxBus" network. (Complete circuit details can be found on
the back cover.)
Specifications
Blanking Widths
NB1, 10 µS; NB2, 70 µS
Current Drain
Approx. 13 mA when turned on, 2 mA off
Size
2.3 x 1.4 inches (58 x 36 mm)
i
Caution:
Some components in this kit can be damaged by static discharge. Before
handling any transistors or integrated circuits, always put on an anti-static wrist strap or touch any
grounded, unpainted metal surface.
