In my last blog I talked about the way I had a power meter nearly build itself. (In retrospect I remember a SolderSmoke episode where Bill claimed the same sort of thing happening with a different version of a power meter.) Friday night I got the chance to build the power meter from my parts.
It only took an hour or so get it put together. The hole for the meter turned out to not be a big deal. The trickiest part was actually getting the BNC jack through the hole in the side. The dummy load was too big and the hole too small to angle the PC board in. I ended up filing one of the corners and put a little force to get it in.
Here is what I ended up with.
Here are some shots of the power meter with my K2. The power meter is connected to the K2 antenna jack and the K2 is keyed. The K2 reports the power from it’s internal power meter. So you can see the K2 calculated power with the deflection of the meter in the new power meter.
The readings are actually fairly interesting. By a serendipitous coincidence 0.5W reads as ~10uA, 2W reads 20uA, 5W reads 30uA and 10W reads 40uA. Couldn’t have gotten that sort of correspondence if I had tried.
And finally after building it I had to plug every transmitter I have into the power meter. The sw20+ showed around 2 watts. Here is a picture of the power meter measuring the output of my homebrew 30m CW crystal transmitter Reads about .5W, which is what I expected but now I have confirmation.
So, all in all I’d have to say I am very pleased. I am going to find some Avery labels and label this guy so when someone goes through the shack after I pass they will know what it is. Not to mention, keeping me from toasting it because I was sure I built it for 100W. Other than that I am ready to build another RF generator to plug in.