Elecraft KNB2 Manual User Manual

K n b 2

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

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)

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.