Build or Buy Dummy Loads for Amateur Radio
Find schematics and guides for constructing various dummy loads, from QRP to high power, or select commercial options for transmitter testing.
Dummy loads are essential tools for any ham radio station, allowing operators to test and tune their transceivers and amplifiers safely without radiating a signal on the air. These non-radiating loads absorb RF power, presenting a 50-ohm resistive impedance to the transmitter. This prevents interference to other stations and protects the final amplifier stage during adjustments or troubleshooting.
Many hams enjoy building their own dummy loads, ranging from simple QRP designs with built-in RF detectors to high-power units capable of handling 500 watts or more. Projects often feature non-inductive resistors immersed in oil for efficient heat dissipation, as seen in designs by N4SPP and W2EB. Operators can also find guides for constructing wet dummy loads using salt water or even combining a dummy load with a power meter, like the AA5TB QRP power meter and dummy load combination, for a compact test solution.
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This project shows how to build a 50-ohm dummy load using non-inductive resistors, oil for heat dissipation, and a simple assembly process. It enables accurate transmitter tuning, testing, and power measurement across LF to UHF bands. The setup allows meter calibration by measuring peak voltage, applying diode drop correction, and calculating RMS voltage and power precisely. Parts are inexpensive and widely available. With proper assembly, this dummy load offers extended service life, accurate readings within 2%, and a reliable alternative to costly commercial wattmeters for amateur radio applications. -
This was a project to make a dummy load or, as the finished thing is more correctly labelled, a fifty ohm resistive load. -
High Voltage Dummy Load 3000 OHMS, 5400 WATTS There are 45 layers of 6 resistors, each one being 400 OHMS @ 20 Watts for a total of 270 resistors -
Dummy load described here can be used for up to 35 watts for short transmissions, and up to 25 watts for longer periods. -
Make your own dummy load with two 100-ohm 5W resistors -
This project was published in the April 2004 issue of the Australian magazine Amateur Radio, and has been designed using parts which are very readily available. -
A homebrew dummy load is usually a combination of several parallel carbon resistors, in order to be able a final resistance of 50 Ohms. -
This article describes a low-cost, low-to-moderate power dummy load, which presents a 50-Ohm resistive load from HF through 440MHz. -
A DIY guide for constructing a low-cost, air-cooled 50-ohm dummy load using carbon film resistors, a heatsink, and an SO-239 connector. -
Building a Dummy Load and Measuring Power Accurately by Ken, K4EAA -
Building a Dummy Load and Measuring Power Accurately -
This is the report of a MFJ-259B analysis of two 100 ohm / 5 watts resistors in parallel partially in italian -
Home made dummy load by M1HOG -
About dummy loads, what are they and how to build one -
Build a wet dummy load using a 1 gallon paint can, at eham forum -
A homemade QRP Dummy Load with built-in RF detector -
Information on equipment manufactured by the Bird Electronic Corporation, wattmeters, RF loads, switches by I0JX -
RF power meter, dummy load, project -
In this article the schematic is of AA5TB QRP power meter and dummy (50 Ohm) load combination -
Use plain water with a little salt added to build your own Dummy Load -
Video, how to build a 130 Watt Dummy Load for HF amateur radio -
An homemade 50 Ohm 140 W dummy load based on an idea and project by ON5DB Renaud. -
If your doing any home brewing gear for ham radio its a great idea to have a dummy load. This will to your radio be the perfect antenna...it will never radiate but your radio sees a perfect 50 Ohm impedance. -
Check your RF power with an easy to read and build digital display -
F5NPV explores the construction of a cost-effective 1KW dummy load for radio enthusiasts. Purchasing a commercial dummy load can be expensive, but with basic materials such as a metal can, resistors, mineral oil, and a heat dissipator, you can build your own. The article provides a simple guide to assembling the load, including the importance of testing for inductance. The DIY dummy load yields impressive performance, with an SWR of 1.2:1 across multiple bands and the ability to handle up to 1KW of power. This budget-friendly solution is a valuable addition to any radio shack. -
This page provides a detailed guide on building a 25 Watt QRP dummy load for hams. It includes a list of required parts and supplies, along with a documentation section. The project is aimed at hams interested in QRP operations and looking to build their own dummy load. The page offers step-by-step instructions and resources to help hams successfully complete the project. -
This will document a custom version of the K4EAA Dummy load done using 20 1K ohm 3 Watt Resistors, Piece of brass sheet, a quart paint can and a BNC connector -
Homebrewing dummy load by M0XPD -
A handy piece of test equipment useful for HF bands, can absorb a 200W modulated carrier for almost 2 minutes. It is housed in a tin and part filled with dry sand that helps in power dissipation -
A simple 50 ohm dummy load to test transmitters. includes a simple RF diode detector to measure the peak voltage, and calculate the power -
This is another variation on the parallel resistor, dummy load. It is perfect for QRP HF operation of 5-watts or less average power, and should be adequate for continuous operation at that level. It's light and compact, about 2-1/2 in length overall. -
MFJ-264 dummy load restoration by VE3LNY -
The use of dummy load is mandatory for off-air adjustment of the transmitters. Build one.