ELECRAFT W2 WATTMETER OWNER’S MANUAL Revision D1, January 2, 2013 Copyright © 2012, Elecraft, Inc.
Contents Introduction............................................................................................................................................... 3 Customer Service and Support ................................................................................................................. 3 Technical Assistance ....................................................................................................................................... 3 Repair / Alignment Service ..............
Introduction The Elecraft W2 is a versatile, auto-ranging RF power and SWR meter that utilizes remote sensing. Up to two remote sensors can be attached, with various power and frequency ranges available (see Sensors, page 19). Sensors use standard CAT5 shielded or unshielded cables. The W2 includes adjustable, high-brightness LED bargraphs for both forward power and SWR. These allow you to keep track of transmitter or amplifier performance at a glance, even in low lighting or across a large room.
Elecraft's 1-Year Limited Warranty This warranty is effective as of the date of first consumer purchase (or if shipped from factory, date product is shipped to customer). It covers both our kits and fully assembled products. For kits, before requesting warranty service, you should fully complete the assembly, carefully following all instructions in the manual. Who is covered: This warranty covers the original owner of the Elecraft product as disclosed to Elecraft at the time of order.
Operation Typically the W2 is inserted between the transmitter and an antenna tuner, if one is used. The W2 then displays the SWR presented to the transmitter. If the W2 is inserted between the antenna tuner and antenna, it will show the antenna's unmatched SWR. The power reading may be less accurate when the unmatched SWR is high. The purpose and operation of each control and indicator on the front panel is described below.
Rear Panel REAR PANEL CONNECTOR NOTES: 1. A power cable is provided with your W2 with a mating connector for the W2 at one end and tinned leads for connecting to a power supply at the other end. An RCA plug is also supplied that you may connect to use the 12VDC accessory output on the back panel of the K3. Normally you must push the power ON/OFF button to start the W2 after 12VDC is applied.
Directional Coupler (Sensor) A directional coupler is used to measure RF power and standing wave ratio (SWR). A typical directional coupler is shown below. At least one sensor must be connected to the W2. Computer Interface The computer interface provides access to advanced functions controlled through your personal computer (PC). A suitable interface cable is included to connect your W2 to your computer through a USB or RS232 port, depending upon the cable you chose when ordering your W2.
SWR Alarm Function If set, the SWR Alarm will cause all the LEDs to flash in unison if the SWR exceeds 3:1 and triggers the relay that opens the circuit between the center pins of the PTT RY phono connectors. The SWR Alarm function must be enabled each time the W2 power is turned on. Send an ASCII character a to the W2 to toggle the alarm on or off. This may be done using the W2 Utility program Command Tester screen.
Tools Required 1. #0 and #1 size Phillips screwdrivers. Use the screwdriver that best fits the screw in each step. To avoid damaging screws and nuts, a power screwdriver is not recommended. 2. Needle-nose pliers. The following tools are strongly recommended: 1. ESD wrist strap. 2. Static dissipating work pad.
Place the 1/8” (2.9 mm) spacer under regulator U3 and temporarily secure it as shown in Figure 2. It is important that the spacer stay in place so it won’t fall out later when you remove the screw to mount the bottom cover. Figure 2. Installing U3 Spacer. Locate the display board assembly. Handle the assembly carefully to avoid misaligning the LED’s Check the front panel board for a nylon screw at the two corners with its head toward the rear (side opposite the LEDs) as shown in Figure 3.
Mate plug P1 on the bottom of the main board with jack J1 on the front panel board as shown in Figure 5. Note that one pin on P1 has been removed and a plug is placed in the corresponding hole in J1. This is to help avoid misaligning the connectors. Be sure the connectors are aligned and fully mated as shown. Figure 5. Mating the Front Panel and Main PC Boards.
Remove the screw holding the spacer between U3 and the pc board and mount the bottom cover as shown in Figure 7. Be careful not to dislodge the spacer. If it falls out, you must remove the cover and replace it as shown in Figure 2. Figure 7. Mounting Bottom Cover. CAUTION Do not put stress on the pc boards when installing the screws in the following step. Secure the bottom cover with four 3/16” (4.0 mm) black pan head screws. No lock washers are used.
Install a 1/4” (6.4 mm) black pan head screw into the mounting hole for the PTT RY connector as shown in Figure 10. Do not tighten this screw! It only threads into plastic. Stop turning when the head reaches the back panel. Even though you don’t tighten the screw, it provides critical support to keep the connector from flexing when connectors are inserted. Figure 8. Installing PTT RY Connector Screw.
Mount 2D fasteners with 3/16” (4.0 mm) black pan head screws at each end of the rear panel cover as shown in Figure 10 (A). Install one fastener at each end of the panel. Do not use lock washers. Mount 2D fasteners with 3/16” (4.0 mm) black flat head screws at each end of the front panel cover as shown in Figure 10 (B). Install one fastener at each end of the panel. Do not use lock washers. Figure 10. Mounting Front and Rear Panel 2D Fasteners.
Mount both side panels on the W2 display unit using three 3/16” (4.0 mm) black flat head screws in each panel. Do not use lock washers. Start all the screws in each side panel before tightening them to make fitting the panels easier. Make a final check of the screw securing U3 on the main pc board with the screw that runs through the bottom cover. Be sure the nut is tight against the board.
Directional Coupler The directional coupler sensor used to provide RF Power and SWR a measurement is furnished completely assembled and tested to ensure the greatest measurement accuracy. We recommend you do not open the unit. The interior of a typical directional coupler is shown in Figure 13. Figure 13. Typical Directional Coupler Sensor Interior View.
Appendix A Parts List W2 Circuit Boards QTY. ELECRAFT PART NO. W2 Main PCB Assembly 1 E850353 W2 Front Panel (FP) PCB Assembly 1 E850354 QTY. ELECRAFT PART NO.
W2 Hardware (E850356) QTY. ELECRAFT PART NO. 2-D Fastener 6 E100078 4-40, Lock washer, #4, Split Z 7 E700004 Black Pan Head 4-40, Screw, 1/4” (6.4 mm), Black, Pan Head 1 E700009 (Typical) 4-40, Screw, 3/16” (4.0 mm), Black, Pan Head 16 E700015 4-40, Screw, 1/2” (13 mm), Black, Pan Head 1 E700030 4-40, Screw, 3/16” (4.0 mm), Black, Flat Head 10 E700025 4-40, Nut, Hex, Zinc 1 E700011 2-56,Screw,1/4” (6.4 mm) ,Pan Head ,Nylon, 2 E700147 4-40, Standoff, Round 1/4” (6.
Cables These cables are provided with both the factory-assembled and kit versions of the W2. DESCRIPTION QTY. ELECRAFT PART NO. Power Cable (An RCA connector is included for use with rigs such as the K3 that have a female RCA power jack for accessories) 1 E850361 1 per Sensor E850368 Serial Data Cable Assembly. USB interface provided unless RS232 specified at the time order is placed. 1 E850483 (USB) Or E850369 (RS232)) DESCRIPTION QTY. ELECRAFT PART NO.
A B C D 1 1 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 0.1 uF SENSOR 2 J1 C12 +5V 5 1 6 7 BAT54 D1 1K 1K 1K 1K 1K R6 R5 R3 R2 R1 C2 0.01 uF 1K R8 R39 R40 R41 R42 1M 1M 1M 1M 1K 1K 1K 1K 1K C15 0.01 uF 1K 1M 1M 1M 1M R14 R13 R12 R11 R10 3 MMBD914 D2 12V C1 0.01 uF 0.01 uF C10 C13 0.01 uF 0.01 uF C21 +5V VLED +5V C11 0.01 uF 0.01 uF C9 C14 0.01 uF 1 1 10K R16 4 C3 0.01 uF VSCL2 SCALE2 VFWD2 SENSE2 VREF2 VREV2 0.01 uF C8 C17 0.
A B C D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 12VUNSW FP J1 3 4 1 2 1 2 12VUNSW +5V 5 S1 TP3 PWM 1 RANGE S3 1 2 3 4 SENSOR S2 ON_OFF 3 4 VLED TP2 SPARE TP1 SPARE 1 1 SRCK RCK SER RANGE SENSOR POWER PWM Pin 4 is keyed 5 RANGE SENSOR POWER +5V C3 1 uF 100K R23 4 +5V +5V +5V +5V +5V 4 C2 0.1 uF C6 0.1 uF C5 0.1 uF C4 0.1 uF C1 0.
SERIAL INTERFACE CABLE 25
Appendix C – Power On Modification With this modification the W2 will turn on when 12VDC is applied without pressing the POWER button. The modification involves soldering a short wire jumper onto the main circuit board. Only the top cover need be removed to install the jumper. Important Operating Notes for Modified Units 1. Pressing the POWER button will turn the unit off, but not on. If you press the POWER button, you must remove and reapply 12VDC to turn the unit on. 2.
