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Reviews For: QRPoMeter power/swr/dummy load by NM0S

Category: QRP Accessories

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Review Summary For : QRPoMeter power/swr/dummy load by NM0S
Reviews: 3MSRP: 50 plus shipping
Description:
Digital QRP power meter, SWR meter. and dummy load.
Product is in production
More Info: http://sites.google.com/nm0s.com/home/qrp-kits
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0035
KE1L Rating: 2022-04-13
Very nice digital power/SWR meter Time Owned: 0 to 3 months.
The original version of the QRPoMeter was designed by Dave Cripe NM0S for the Four State QRP Club (4sqrp.org). That version was retired, but Dave now offers an updated version of the kit, the QRPoMeter+, through his own business, NM0S Electronics. I have the new version, and built it in April 2022. This version is rated for up to 15W, an improvement over the 8W rating of the original. Power is displayed in 10mW increments. The meter is powered by a 9V battery, with no option for running it from a power supply. (Inexpensive panel meters must run from a power source that is independent of the device under test; they cannot share a common ground. Requiring separate battery power is an easy way to make sure that condition is met.)

The kit comes with clear directions and is easy to build. Unlike the earlier version, this new one does have a few SMD parts -- but don't panic, they are huge SMD resistors that are easy to solder by hand. (I chose to use a hot air station and solder paste because I have those things on my bench, but they saved very little time.) I had one each of the 0.01uF and 0.1uF capacitors left over after building; they were provided as spares. (The parts count was otherwise exact.) The tools required for assembly are a good soldering iron, some solder wick (aside from fixing any assembly errors, there is one bridge on the panel meter that you have to desolder), flush cutters, a wire stripper, and a Phillips-head screwdriver. You will need a couple of rubber bands at one point to hold the case parts together.

You will need a DVM, a QRP transmitter, and a very small flat screwdriver (one that comes with a set of alignment tools is best) to calibrate the meter. There are two adjustments. The first one is to set the regulated voltage to exactly 5.00V; that is done with a 10 turn trimmer on the board. The other is to adjust the digital panel meter for correct output power; that is done with a tiny trimmer on the panel meter.

I spent about three hours assembling the kit; two hours one day to solder all the components to the board, and an hour the next day to wire up the panel meter, assemble the case, and align the meter. There are no awkward steps in the process, just lots of components to install.

Once you are done, you have a handy device for measuring the power output of your QRP rig and the SWR of your antenna. There are two toggle switches; one turns the meter on or off, the other switches between power and SWR measurement. Power measurements are done into a dummy load on the circuit board. SWR measurements are done through a resistive bridge, so the rig never sees an SWR higher than 2:1 while you measure. When you're done, turn the meter off and the antenna is connected directly to the rig.

This is NOT an in-line power or SWR meter. The only way to connect the rig directly to the antenna is to turn the meter off.
WO7T Rating: 2021-04-23
QRPoMeter is FB Time Owned: 0 to 3 months.
Sold my OHR WM-2 a few years back and now of course OHR is no more, but equally capable, accurate, and of newer technology is this QRP meter from NM0S, who has also designed many kits for the Four States QRP Group.

I particularly like the built in Dumy Load (15W), protecting QRP radio finals, and in OFF position it is bypassed from radio direct to antenna. It doesn't see the wattmeter inline.

The kit went together per the instructions and a small tip soldering iron in about 3 hrs. Alignment was flat out simple, as long as you have a multi-meter that reads voltage. You set one pot to a 5.0 volt reading, and you read a voltage off a testpoint to precisely set digital display potentiometer setting. Took 5 minutes to do it all.

Even if you could buy an OHR wattmeter today , I would recommend going with this one, unless digital vs. analog is your major decision point.
K4LXY Rating: 2019-06-01
Great QRP meter Time Owned: 0 to 3 months.
This is a digital QRP power meter, SWR meter. and dummy load. It is beautifully
designed and built. Construction was straightforward, even though no photos
were provided with the included printed instructions. Calibration is simple.

I decided to mount the 3 ICs in sockets (not provided), which was a mistake: the
extra height causes the 14-pin IC to interfere with the pot on the back of the LCD
board.

Another great design and product from David Cripe, NM0S! I only wish I had
discovered it sooner, before buying and building other ones that aren't as versatile
and/or precise.