Now that a lot of you have your boards, you will probably want to get building. There is a preferred building sequence that will help you test your system as you build. First, build the power meter. Calibrate it and set the voltage output to produce +5.0 VDC MAX at -10dbm. On my power meter, the output is set a little lower. The maximum input to the UNO R3 is +5.0 VDC. Anymore and you run the risk of damaging the UNO. So, my meter is set at 4.55 VDC for -10 dbm. When you guys get to the calibration point, there are several ways to do it based upon the equipment you have. If you have access to a HP8640B generator or other high quality generator, you can use it to do the calibration. Or if you have a good 5 watt power meter and a QRP transmitter, you can use them. There are a lot of different ways to do the calibration. We will be discussing them with you.
Once the power meter is built and operational, you can then build the SSNA. Before you build the SSNA, try downloading the software, compiling it and installing it on your UNO R3. That will give your little computer a quick test. Actually, this test can be done anytime. After building the “shield” board (the board that plugs into the computer), decide where you want to take the output from the DDS board. Jim, has written up some options for you. Depending on where you extract the output, you may have to modify T1 on the shield board. More on that later. You will be able to test the output level of your SSNA using your power meter. You will be able to set the calibration of the DDS by using a well calibrated Frequency meter or by listen for zero beat against WWV on a receiver.
If we can get everyone to follow this build sequence, we can help one another, as a group, to succeed.
"building something without experimenting is just solder practice"