ELECRAFT KAF2 Betriebsanleitung PDF herunterladen

Elecraft • www.elecraft.com • 831-662-8345

E L E C R A F T K A F 2

A U D I O F I L T E R a n d R E A L - T I M E C L O C K

Assembly and Operating Instructions

Introduction

The KAF2 option supplements the K2's crystal filters with effective, low-noise audio filtering. It also adds

a real-time clock, allowing you to check the time or date with a tap of the K2's D I S P L A Y button.

Audio Filter

The KAF2 includes a passive, balanced low-pass filter (LPF) that is in-circuit at all times. It provides

significant attenuation of signals above 3 kHz, including hiss, high-pitched splatter, and carrier leak-

through. The LPF is particularly useful on quiet bands, when using headphones, or with small antennas.

Also included is a narrow, active band-pass filter for CW or data use. The center frequency of the filter is

tunable via two potentiometers. The A F I L switch on the K2 front panel selects either O F F (LPF only),

A F 1 (first CW filter stage), or A F 2 (both stages). The operator can choose to treat both CW filter stages as

a single setting (A F 2 ) by installing jumper W1.

Real-Time Clock

The real-time clock displays 24-hour time, as well as date. You'll find the clock convenient for field

operation since it eliminates the need to bring a separate clock. Time can be easily set using the B A N D +

and B A N D - switches. The on-board lithium backup battery will power the clock for up to several years.

Specifications

Low-pass filter Flatness: better than 1 dB, 0.5 to 2 kHz; Atten.: approx. -20 dB at 4 kHz

Band-pass filter Bandwidth: approx. 80 Hz @ -3 dB, 270 Hz @ -20 dB (two stages cascaded)

Clock Accuracy +/- 20 ppm (+/- 1.7 seconds per day) at 25 degrees C

Date Formats MM-DD-YY or DD-MM-YY; handles all calendar months and leap years

Current Drain Approx. 10 mA

Size 1.5" (L) x 1.5" (D) x 0.5" (H) (3.8 x 3.8 x 12 cm)

Caution: Some parts in this kit can be damaged by static discharge. Before handling any

transistors or ICs, put on an anti-static wrist strap, or touch a grounded, unpainted metal surface.

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Inhaltsverzeichnis

Seite 1 - E L E C R A F T K A F 2

Elecraft • www.elecraft.com • 831-662-8345E L E C R A F T K A F 2 A U D I O F I L T E R a n d R E A L - T I M E C L O C K

Seite 2 - Parts Inventory

103-Volt Battery InstallationTurn the K2 off. Remove the top cover or left side panel to gain access to the KAF2.The (+) side of the 3-volt battery mu

Seite 3 - Assembly

11Using the Audio FilterLow-Pass Filter (LPF)The LPF is always on, providing high-pitch QRM and noise reduction in all modes. This effect will bemost

Seite 4

12Customizing Filter ComponentsGain: The overall gain of the KAF2 is intentionally kept low: 0 to 1 dB in O F F and A F 1 modes, andslightly higher

Seite 5

13TroubleshootingIf your symptoms are not covered below, check the orientation of all components, connectors, and wiring;look for cold solder joints;

Seite 6

14Circuit DetailsRefer to the schematic diagram, page 16.The filter circuits of the KAF2 are inserted between the receiver's product detector and

Seite 7 - Control Board Preparation

15(This page intentionally left blank)

Seite 8 - Low-Pass Filter

1632.768 kHz3.9K10K10KRP1R9R10X13 43.9KRP16 5W. BurdickE. SwartzElecraftRev. Sht. DateBy1 of 1= On bottom of PC board.GNDOUTINMCLROSC1OSC2RA2RA3RA4V

Seite 9 - Band-Pass Filter

2Parts Inventory The table below lists all parts in the kit. Refer to the K2 manual parts lists for photographs.Ref.DescriptionPart No.QtyBT1Battery,

Seite 10 - Final Assembly

3Firmware RequirementsTo use the KAF2's real-time clock, you'll need main microcontroller firmware revision 2.01 or later. If youhave an ear

Seite 11 - Using the Audio Filter

4i Some components will be installed on the bottom of the board. These components must beseated down onto the board as far as they'll go. In the

Seite 12 - Using the Real-Time Clock

5Install trimmers R1 and R2 (5 k) as indicated by their component outlines on the top side of the board.Install resistor network RP1 (3.9 k, 8 pins).

Seite 13 - DC Voltage Chart

6Make sure that the 2-pin male connector is flat against the PC board, then solder.Install the 5-pin and 3-pin male connectors on the bottom side of t

Seite 14 - Circuit Details

7Control Board PreparationIf the firmware on the Control board must be upgraded, do so now. Follow all instructions suppliedwith the upgrade, but leav

Seite 15

8Installationi Two screws are used to hold the Control board to the Front Panel board. The screw on the left end(as viewed from the K2 front panel) w

Seite 16 - Elecraft

9Move S1 on the KAF2 module to the IN position, which puts the KAF2's low-pass filter in-circuit.You should hear a significant reduction in noise