Elecraft XG50 User Manual

ELECRAFT XG50 SIGNAL SOURCE

Ref

Qty

Description

Part #

R1 1 Res, 5.1K Ω 1% (grn, brn, brn, brn, brn)

E500109

R2 1 Res, 10 Ω 5% (brn, blk, blk, gold)

E500054

C1,C2

2

Cap, 0.1 uF, 50V 20% mono

E530020

J1 1 2.1mm power connector

E620026

J2 1 BNC Jack right angle

E620020

U1 1 LM78L05 5 volt regulator

E600029

U2

1

49.380 TCXO ±5 ppm

E660033

PCB

1

XG50 Printed Circuit Board

E100451

1

Power Cable

E980171

Rev D , N o v emb e r 26, 2 0 1 2

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

The Elecraft XG50 is a simple 49.380 MHz signal source specifically designed for use with the KX3 Extended
VFO Temperature Compensation Procedure. Powered from a 12VDC source, the XG50 produces a stable -36
dBm signal.

Specifications

RF Output Level 10 mv p-p (-36 dBm) into 50 ohms
Frequency 49.380 MHz, ±5 ppm

Stability Approximately ± 2 Hz
Current Drain Less than 25 ma @ 12 VDC
Operating Voltage 8 – 15 VDC
Size PC board: 2.5"L x 1"W; 3.3"L including BNC connector

Parts Inventory

†

Assembly

 Orient the printed circuit board with the silk-screened side up and the title “XG50” at the top.
 Install R1 and R2 at the indicated positions.

 Install C1 and C2 at the indicated positions.
 Install U1 at the indicated position, being careful to orient the flat on the device so it matches the silk

screen outline.

 Install U2 at the indicated position. The black dot on the device denotes pin 1. When correctly inserted

into the board, this dot will be oriented closest to the square PIN 1 hole.

 Install J2, the BNC connector at the position indicated on the PC board silkscreen
 Install J1, the power connector at the indicated position on the PC board silkscreen.

†

After initial 8 hour aging period.

1

Initial Test

Schematic

Bare Board

Assembled

 Observing polarity, attach 12 VDC to the unit using the supplied power cable, inserting the plug into J1.
 Using a frequency counter or oscilloscope, verify an output of 49.380 MHz ± 247 Hz.
 A transceiver tuned to 49.380 MHz or VHF radio tuned to the 3

be used to verify operation.

rd

harmonic of 148.140 MHz may also

Using the XG50

 Prior to initial use, power the XG50 for 8 hours. This should only be done once and while not required

for normal operation, will help minimize oscillator drift. When using the XG50 as part of the KX3
Extended Temperature Compensation Procedure, locate it away from the radio, in an area free from
drafts and heat sources. This will help minimize frequency drift during the procedure. A 3’ (1 M) 50
ohm patch cable may be used to connect the output of the XG50 to the KX3.

2