Elecraft KXFL3 Filter Option - Manual

1
Elecraft
®
KX3
KXFL3 Roofing Dual-Bandwidth Filter
Installation and Calibration Instructions
Revision A2, June 14, 2012
Copyright © 2012, Elecraft, Inc., All Rights Reserved
Introduction
The KXFL3 is a high-performance, narrow-band analog filter module that helps reject strong signals that could
cause receiver blocking (desense) or intermodulation distortion. It adds two additional bandwidths to the KX3
that are automatically selected as the receive bandwidth is adjusted.
Installation involves installing the KXFL3 plug-in module in your KX3 and then calibrating the filter for proper
operation. No test equipment is required to calibrate the filter although a signal generator may be used, if
available.
CAUTION
The KXFL3 module and many components inside your KX3 may be damaged by
Electrostatic Discharge (ESD) simply by touching them or a circuit board containing
them unless you take specific steps to prevent such damage. See Preventing
Electrostatic Discharge Damage on page 2 before opening the package containing the
KXFL3 module or working inside your KX3.
Specifications
Filter type: Two filters, each having dual balanced Butterworth sections
Gain/phase match: Typ. 0.1%. Additional matching accuracy provided by DSP
techniques.
FL2: 1500 or 3000 Hz low-pass, depending on demodulation method in use.*
FL1: 500 or 1000 Hz low-pass, depending on demodulation method in use.*
* The narrower bandwidths apply in all modes except when Weaver-mode SSB demodulation is
being used. Filters switch in at predetermined points in each mode, varying with passband center
pitch, width, and shift amount.