Elecraft XG2 User Manual

ELECRAFT XG2 RECEIVER TEST OSCILLATOR

Rev F, March 28, 2012

Copyright © 2012, Elecraft, Inc., All Rights Reserved

Introduction

The Elecraft XG2 is a crystal oscillator with accurate 1 µV and 50 µV output levels. It's
ideal for receiver test and alignment. The 1-µV output can be used to measure a receiver's
sensitivity, while the 50-µV output is useful for S-meter calibration. Switch-selected
output frequencies of 3579, 7040, and 14060 kHz provide convenient test signals on 80,
40, and 20 meters; harmonics of these frequencies can be used for measurements on
higher bands. The XG2's unique oscillator stage runs at an extremely low level,
eliminating the need for interstage shielding. A red LED is provided to indicate power-on
and another red LED is provided to alert the operator to accidental transmit into the
XG2's output.

Specifications

RF Output Level 1 µV (-107 dBm) and 50 µV (-73 dBm) into 50 ohms
Output Accuracy Better than +/- 2 dB at 25 deg. C (+/- 1 dB typical)
Frequency 3579.5, 7040.0 and 14060.0 kHz +/- 1 kHz at 25 deg. C
Reverse Protection 5 watts for 4 seconds, 10 watts for 2 seconds (typical; not

guaranteed)

Current Drain About 250 µa from on-board 3-V, 220 mA-hr battery (est. life 800

hours)

Size PC board: 3"L x 1.5"W; 4.3"L including BNC connector

Parts Inventory

Ref Qty Description Part #

R2 1 Res, 18.7 k 1% (brn, gry, vio, red, brn) E500127

R3 1 Res, 16.5 Ω 1% (brn, blu, grn, gold, brn) E500122

R4 1 Res, 57.6 Ω 1% (grn, vio, blu, gold, brn) E500124

R5 1 Res, 57.6 Ω 1% (grn, vio, blu, gold, brn) E500124

R6, R7 2 Res, 348 Ω 1% (org, yel, gry, blk, brn) E500123

R8 1 Res, 1.24 k 1% (brn, red, yel, brn, brn) E500126

(parts inventory continues on next page)

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Ref Qty Description Part #

R1, R9 2 Res, 10 k 5% (brn, blk, org) E500015

R13 1 Res, 5.6K 5%, (grn,blu,red) E500007

C2, C5 2 Mono Cap, 47 pF (47 or 470) E530014

C1 1 Mono Cap, 18 pF (18 or 180) E530212

C3, C4 2 Mono Cap, .047 µF (473) E530131

C6 1 Mono Cap, 33 pF (33 or 330) E530013

D5 1 Red LED, round E570025

D2 1 Red LED, rectangular E570007

D1, D4 2 Diode, 1N4148 E560002

U1 1

Q1 1 Transistor, 2N3904 E580017

X1 1 Crystal, 14060 kHz E850211

X2 1 Crystal, 7040 kHz E660023

X3 1 Crystal, 3579.545 kHz E660029

BT1 1

S1 1 Miniature slide switch E640009

J1 1 BNC Connector E620020

S2 1 Large slide switch E640019

S3 1 Rotary switch, 3 position E640027

Misc. 3 Self-adhesive mounting feet E700024

Misc. 1 Battery Holder E980086

Misc. 1 XG2 Printed Circuit Board E100255

Ref. Diode, 1.22 V, ZXRE125DR or
ZXRE1004D

Lithium 3V battery, CR2032 (Inside envelope
E850058)

E600081

E980039

Assembly

Sort the resistors by value. Some of the color bands may be hard to read; use a



magnifying glass if necessary. A Digital Multimeter (DMM) should be used to confirm
the values.

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 Orient the printed circuit board with the silk-screened side up and the title

“XG2” at the bottom.

 Install the following resistors in their indicated positions, starting at the top of

the PC board and working down. (Complete the left column, below, then the

right column.) Note: The XG2's output level accuracy depends on each
resistor being installed in the correct location.

__ R7, 52.3 Ω, 1% (grn, red, org, gold, brn)
__ R8, 1.24 k, 1% (brn, red, yel, brn, brn)
__ R6, 52.3 Ω, 1% (grn, red, org, gold, brn)
__ R5, 57.6 Ω, 1% (grn, vio, blu, gold, brn)
__ R4, 348 Ω, 1% (org, yel, gry, blk, brn)

__ R3, 16.5 Ω, 1% (brn, blu, grn, gold, brn)
__ R2, 18.7 k, 1% (brn, gray, vio, red, brn)
__ R1, 10 k, 5% (brn, blk, org)
__ R9, 10 k, 5% (brn, blk, org)
__ R13, 5.6k 5% (grn, blu, red)

 Sort the small ceramic capacitors by value. Install the capacitors listed below:

__ C3, .047µF (473) __ C4, .047µF (473) __ C2, 47pF (470)

__ C1, 18pF (180) __ C5, 47pF (470) __ C6, 33pF (330)

 Using your DMM, measure the resistance to ground at each of the points listed below.

Any incorrect reading could indicate that you have one or more resistors installed

incorrectly.

__ junc. of R7, R8: 48-52 ohms __ junc. of R6, R8: 48-52 ohms
__ junc. of C4, R4: 385-425 ohms __ junc. of C1, C2, R2: 18-19 k

 Install diode D1 (1N4148) with the banded end nearest resistor R7. NOTE: The silk-

screened outline and band on the Rev A board is backwards!

 Install diode D4 (1N4148). The outline for this diode is correct. Align the banded end

with the band on the silk-screened outline. The band will be at the end nearest the edge of

the board.

 Install the Red LED at D2. Insert the long lead into the square pad.
 Install the small round LED at D5. Insert the long lead into the square pad.
 Install J1, the BNC connector, on the edge of the board as shown by its outline (see right

side photo on page 8).

 Install the battery holder for BT1.
 Install switches S1, S2 and S3 in their indicated positions.
 Install U1 and Q1. Align the flat side of the packages with the flat side shown on the

component outline. Note: When U1 is correctly installed, its labeled side will face
away from S2.

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