My testing projects were fun, and consumed much of my time during 2021. Our main focus was on RFI and antennas.
Once you have a bunch of test equipment, you like to find reasons to use it. My test gear includes spectrum analyzers, oscilloscope, signal generators and a vector network analyzer for antennas and transmission lines.
During spring of this year, my testing projects focused on so-called “QRM Eliminators”. This led to my RFI cancellation shootout, featuring the most popular analog noise reduction gear. I was fortunate enough to get extended loan of the DX Engineering NCC-1 and MFJ 1026. I added these to my Timewave ANC-4 and RA0SMS X-Phase devices and put all through extensive tests.
Surprise, they all worked well to various degrees at reducing radiated RFI from neighbors. While the X-Phase can be assembled for as little as $21, and the DX Engineering NCC-1 over $800, each did the job. The trick is not so much which device you use, but how well you assemble and position a noise antenna.
During summer, my testing projects shifted to building and testing a flying saucer resonator vertical antenna. This design was published in May 2017 QST and is popular with mobile HF operators. I adapted the design using a 3D printer to fabricate the resonator disks, and mounted 80 and 30 meter resonators on an eight foot aluminum mast. Performance was good on 30 meters, not so much on 80.
During testing with my NanoVNA, I learned a lot about resonance and radiation resistance, in particular about vertical antenna efficiency. You can read about these activities using the links above. Much thanks to Peter VE6KK for his help on both these efforts.
My Testing Projects – 2021 Odds and Ends
Other projects during the year included using my TinySA spectrum analyzer to inspect all of my coaxial connections for RFI ingress in and around the shack. I also attached the TinySA to my RFI hunting loop.
I also added the wonderful Sound Card Oscilloscope to my collection of test equipment. With this, I did some extensive analysis of impulse-type RFI working its way into my SDR receivers.
And, in case you haven’t noticed, SDRplay radios can be used as spectrum analyzers with some great add on software. Happy testing during 2022!