20W Dummy Load Kit Assembly Guide

Assembly Procedure

1. Prepare your workspace

   Find a clean, well-lit area to work. Collect your kit components and tools. You will need the following:

   • Soldering iron
   • Flux-core solder, or solder and solder paste
   • Small wire cutters
   • Needle-nose pliers (optional)
   • Multimeter for testing (optional)
   • Helping hands, or similar device, to hold components while soldering

2. Inventory the parts

   Open your project bag and verify that all the components are there. You will have the following:

3. Prepare and install the resistors

   Install the resistors on the PCB at the locations marked R1-R8. All the resistors are identical, so they can go in any of the marked spaces; orientation isn't important since the resistors are not polarized. If you're experienced with electronics, you can install all the resistors on your own now. If you're new to soldering, follow along with my instructions.

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   1. Prepare the resistors

      Bend the leads of the resistor so that they are at a 90-degree angle to the body of the resistor. This will make it easier to install the resistor on the PCB. Use the PCB as a guide to determine the correct lead spacing.

      

   2. Insert resistors R1-R4

      Insert the first four resistors into the PCB at the location marked R1-R4. The resistors can go in either way; there is no polarity to worry about. Once installed, bend the leads outward slightly to hold the resistors in place. The resistors should be flush with the PCB and on the printed side of the board.

      

      Understanding Your Options - Resistor Height

      There is a balancing act in play here. By placing the resistors flush with the PCB, we're limiting the air flowing around them, which limits the amount of heat/power they're able to passively dissipate. However, by keeping the resistor leads short, we're reducing the parasitic inductance in the circuit, thereby lowering the SWR of the device at higher frequencies and increasing its efficiency. This is a trade-off that I made based on my personal preferences; you are welcome to make other choices.

   3. Solder the resistors

      Hold the soldering iron to the pad and the lead of the resistor on the back of the PCB. Touch the solder to the joint, not the iron. The solder will flow onto the pad and the lead. Remove the solder first, then the iron. The joint should be shiny and smooth. Repeat this process for all the resistors.

      

   4. Trim the leads

      Use the wire cutters to trim the excess leads from the resistor on the back of the PCB.

      

   5. Repeat for the remaining resistors

      Repeat the above steps for the remaining resistors, installing them at the locations marked R5-R8.