Elecraft W1 User Manual

Assembly and operating manual

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

E L E C R A F T

W 1 P o w e r M e t e r

Assembly and Operating Manual

E740100: Revision D, October 12, 2008

Introduction

The Elecraft W1 is a versatile RF power and SWR meter than can be used with any transmitter from QRP levels to 140 watts
output from 1.8 to 30 MHz. The W1 automatically selects the proper power range of up to 1.4, 14 or 140 watts and indicates
the peak forward power and SWR on built in LEDs. The power and SWR is also available through a connector as RS232
serial data for display on a computer or to control other equipment.

The W1 Power meter is designed to be used as a stand-alone unit that may be powered from a self-contained battery or an
external power source. Optionally, it may be built into existing equipment or an enclosure of your choice. See Assembly
Options on page 3 for more information.

The W1 uses no surface-mount technology, so it’s an ideal project for first-time builders.

Specifications

Size: 5-3/8” x 2-11/16” (13.7 cm x 6.8 cm).
Internal Power: 9V battery.
External Power: 7-14 V (8 V min. recommended).
Current Drain: 10 mA idle, 30 mA with 10 LEDs illuminated.
Power Range; Auto-ranging, 1.4, 14 and 140 watts.
Accuracy: 0.5 dB typical.
Frequency Range: 1.8 to 30 MHz.

Tools Required

You will need the following tools to build this kit:

 Fine-tip temperature-controlled ESD-safe soldering station with 700 to 800F tip (370-430C). Recommend a spade

tip no greater than 0.05” (1.3 mm) wide.

 IC-grade solder (Kester #44 or equivalent). Small diameter solder (e.g. .031”) is easiest to work with on small

printed circuit boards. DO NOT use acid-core solder, water-soluble flux solder, additional flux or solvents.

 Needle-nose pliers.
 Diagonal cutters.
 Small, #2 Phillips screwdriver.
 Small wrench or driver for 4-40 nut.
 Digital Multimeter (DMM) with voltage, resistance and diode-checking functions is useful for confirming the value

of components. A DMM with capacitance measurement capability is desirable, but not required.

 Desoldering tools and supplies are invaluable. Narrow solder wick or a good vacuum desoldering tool such as the

Soldapullt® model DS017LS are recommended.

 A conductive wrist strap and anti-static mat is recommended (see ESD-Sensitive Parts below). Wrist straps and mats

are available at very low cost from Jameco, Mouser, and other electronics suppliers.

Refer to www.elecraft.com for tool sources and solder recommendations.

Parts List

We strongly recommend that you do a complete inventory before beginning assembly. The inventory helps you correctly
identify all the parts to avoid mistakes during assembly.