Download Print this page

Macsense Connectivity Digital Wattmeter DWM-4 Product Manual

Digital wattmeter

Advertisement

Quick Links

- 1 -
Welcome: Thank you for your purchase of the DWM-4 Digital Wattmeter. The DWM-4 represents
an advancement in technology that has never before been available in RF power measurement.
With the integration of a microprocessor to existing RF sensor technology, the DWM-4 offers the
flexibility of digital processing while keeping the interface to the user simple and straightforward.
Introduction: The DWM-4 is a four channel, microprocessor controlled RF wattmeter. It consists
of two main parts, the display unit and the remote sensor. The display unit has a 2 by 16 backlit
LCD module that provides the user with information about the RF that is being sampled by the
remote sensor. The user can simultaneously view forward power, reverse power and swr on the
same display for instant analysis of the antenna system.
There are two types of remote sensors. The HF/QRP sensor can sample RF from 1.8 to 54 MHz
and up to 150 watts. The VHF/UHF sensor can sample RF from 140 to 160 and 420 to 470 and up
to 150 watts. The modular design allows for the maximum flexibility with the minimum cost. The
remote sensor is supplied with a six-foot cable to connect to the display unit. A longer cable can be
used for truly remote sensing.
The display unit is controlled by a selection of menu screens on the display. The menu screens
and the data on them are selected by the two pushbuttons (Menu and Select) on the front panel.
Status information is also shown on the display.
Building the Kit: If you purchased the DWM-4 as a kit, the following instructions will give an
overview of how to assemble it. If the DWM-4 was purchased assembled, you may still want to
review the assembly instructions to become more familiar with the unit. If you want to get right to
operating the unit, skip the assembly instructions and go right to the operation section.
Before getting the soldering iron out, go through all of the parts in the kit and familiarize yourself
with each component and its placement. Most of the parts are common, but there may be a few of
them that may be new to some builders. There are just over 100 parts and 200 solder connections,
so take your time.
The instructions are written to assemble the unit using the height order of the parts form lowest to
highest. This will assist the builder in the installation of the components. There are various photos

Advertisement

loading
Need help?

Need help?

Do you have a question about the Digital Wattmeter DWM-4 and is the answer not in the manual?

Questions and answers

Summary of Contents for Macsense Connectivity Digital Wattmeter DWM-4

  • Page 1 - 1 - Welcome: Thank you for your purchase of the DWM-4 Digital Wattmeter. The DWM-4 represents an advancement in technology that has never before been available in RF power measurement. With the integration of a microprocessor to existing RF sensor technology, the DWM-4 offers the flexibility of digital processing while keeping the interface to the user simple and straightforward.
  • Page 2 in the assembly instructions to assist the builder. These can be used for parts identification and PC board placement. Assembly: You will first install (locate, place, and solder in place) the parts on the DWM-4 Main PC board. Use the silk screen layout in the back of this manual to assist in locating where parts are to be installed.
  • Page 3 Install the socket for U1. Note the orientation of the socket. The flattened corner goes in the upper left, toward the 14-pin DIP socket for U3. Do not install U1 (the 68HC11) until later. Install the 8 MHz crystal. Install the electrolytic capacitor, C2, 10uf radial. Note the polarity. Install the 1/8"...
  • Page 4 Install the LCD Module in the chassis. Use the 4 black flat head screws, the two #4 nylon washers and four nuts. Use the washers on the Status/SWR side of the chassis. Do not over tighten the mounting screws. Install the SPST toggle switch (SW1) in the chassis in the Power On position. Remove the nut and one washer from the switch.
  • Page 5 You are now ready to mount the DWM PC board in the chassis. Install the DWM-4 PC board in the chassis using four screws, nylon spacers, washers and nuts. Do not drill out the holes in the PC board Install U1 (the 68HC11) by carefully pressing it into place in its socket. Note that U1 has a flattened corner that should match the socket.
  • Page 6 Install the .01uf monolithic capacitors, C1 and C2. Install 1/8" stereo jack. Unwrap the enclosure. Install the SO-239 connectors. Put one #4 screw in hole and place two nuts on the screw. Repeat with the other three screws. Do not tighten them at this time. Place the PC board onto the SO-239s.
  • Page 7 HF/QRP Remote Sensor Assembly Instructions Wind T1 with 10 turns using the red and green #28 gauge wire. T1 is the small, black toroid just under one half inch in diameter. See picture below and wind this in bifiliar fashion by using two lengths of wire and winding them at the same time.
  • Page 8 Install C4, 3.5-13 pf trimmer capacitor. Note that C4 has two pins that are common (connected). They should line up with the two holes in the PC board that are connected together with a trace on the bottom. Install T1. It lies flat against the PC board and the #18 wire will pass through the center (you will install this later).
  • Page 9 - 9 - Installation: The DWM-4 operates from an 11 to 15 volt DC power source. The current requirement is about 75 mA. Be sure to use a power supply or power adapter that meets these requirements. The coaxial DC jack on the back of the display unit will accept a plug with an OD of 5.5 mm and ID of 2.5 mm.
  • Page 10 - 10 - menu offers information about each of the four sensor inputs. Some items are common across different menus. There are two basic wattmeter modes: setup and operate. During setup, you can select bargraph or numeric display, peak or average display, set SWR alarms, and select which sensor type is connected to each input along with a power range for each sensor.
  • Page 11 - 11 - At a minimum, a 100 W HF radio and good 50ohm dummy load can be used to calibrate the HF sensor and display unit. Even if you know how much power your radio emits, consider using an additional wattmeter of known accuracy to assist you during the calibration process.
  • Page 12 - 12 - was installed correctly. Make sure U3 is installed correctly. Check D1 for polarity. Check the SIP resistor (RP1) for proper orientation. No Display: Make sure the 14-pin ribbon cable is installed and oriented properly. Be sure the nylon washers are in place on the two nuts closest to the outside.