QRPometer Assembly Manual
Copyright – 2012 David Cripe
NM0S The 4 State QRP Group
Introduction
Thank you for purchasing a QRPometer. We hope you will enjoy building it and and find it a useful
addition to your QRP station. This kit was conceived to fill a need within the hobby for an inexpensive,
highly accurate VSWR and RF power meter for QRP power levels. The QRPometer uses simple analog
signal-processing circuitry to provide a set of essential measurement features not previously available in a
single unit.
High quality, double sided, printed circuit board construction is used, with solder mask and silk screened
component reference designators. All components are through-hole for easy assembly. NO toroids are
required. All controls and jacks are PCB mounted, and a single, four conductor ribbon cable is the only
wiring necessary. The QRPometer can be constructed by beginners as well as experienced builders.
Construction time is approximately 3 hours, depending on experience level. The only equipment required
for calibration of the QRPometer is a digital voltmeter, and a QRP transmitter.
First Steps
Before getting started with building the QRPometer, take some time to organize and familiarize yourself
with the parts provided and check them against the Bill of Material. Building over a cookie sheet is
recommended to minimize parts being lost. To prevent static damage, it is recommended that the ICs not
be removed from their anti-static packaging until you are ready to install them. If parts are missing in your
kit, send an email to our kitter Rich Fowler, K8MEG, at [email protected]. He will promptly
provide replacements.
Schematic and parts-placement files are provided as part of documentation package. It is highly
recommended to print a couple of copies for reference during construction. As you build, use a
highlighter to mark off parts that have been soldered onto the PCB on one copy. When you think you are
done, you can check that copy to verify that all of the parts have been installed.
Step 1 – Connectors
The first step of assembly is to install the connectors on the PC board. J1 and J2 are RCA connectors for
RF input and output from the PC board. Insert them into the board, and solder the center tab first. Make
sure the connectors are flush with the board, and reheat the center pin joint if necessary to reposition them.
Then, solder the three mounting tabs of each connector to the board, and trim flush with the board.
( ) J1 – RCA connector
( ) J2 – RCA connector
Connectors J3 and J4 are the PC-mounted snap-on connectors for the 9v battery. Notice that J3 is the
male, and J4 is the female, and are shown on the silkscreen. To assure proper positioning, snap a 9v
battery to the clips prior to soldering. Again, make sure the connectors are flush with the board, and
