Also, it wasn’t the best choice of footprints – it does not match ANY of the PCB mount BNC connectors that I saw on Amazon – something I really should have checked beforehand. Note the soldered wire on the bottom view? Unfortunately, the PCB footprint intended for a BNC connector mounted on the PCB board that I chose was not a wise choice, and I forgot to ensure it was connected to ground. The result was this PCB: Circuit board for K6BEZ Antenna Analyzer Top View Circuit board for K6BEZ Antenna Analyzer Bottom View I then proceeded to reproduce the schematic in KiCAD, and lay out a PCB based on an Arduino Micro and the aforementioned direct digital synthesis module. The one I used, available from HiLegto on Amazon, is labelled HC-SR08 on the back side of the DDS PCB. IMPORTANT: Not all of the DDS modules based on the AD9850 use the same pinouts. The Arduino Micro, in turn, communicates with a PC to control its functions. The original output, as well as any reflected signal coming back from the antenna are then each half-wave rectified and filtered, and fed to a pair of operational amplifiers in a single IC, which are then fed to the Arduino Micro’s analog inputs. That is then fed to an antenna, and to an SWR bridge – 3 51 ohm resistors with the antenna and its ground as the fourth leg of the bridge. The AD9850 is controlled from an Arduino Micro microcontroller, and is used to generate sine wave outputs from 1MHz to 30MHz. The basic design uses an AD9850 direct digital synthesis (DDS) module to generate the testing output signal. PDF of testing results for breadboard version of the analyzer. The results from this test (as a PDF) are in the link below and gave me enough confidence to proceed with my project. I first constructed the unit on a breadboard, using a couple of germanium diodes and an Arduino Uno I had on hand to make sure I had the circuit correct and that it functioned reasonably correctly. □īut I did spot the K6BEZ Antenna Analyzer, and it piqued my interest. Had I been aware of this unit, I probably would have just bought one. I am also working on a so-called “magnetic loop” antenna, so I realized I was going to need to be able to analyze its impedance, and to tune it, so I started researching antenna analyzers online.Īt the time I had not yet spotted the “Nano Vector Network Analyzer” units available on Amazon and eBay – they didn’t show up on a search for “Antenna Analyzer”. Discussion of using a balun as an unun online at.I found Nooelec’s support exceptional – and indeed they ended up refunding the price for the unit, though I felt that was not necessary for them to do. But there is no reason why a balun cannot also function as an unun, as near as I can tell. I had some questions about it because it indicated it was an unun (unbalanced to unbalanced device), but when I received it, I found it could not be wired as the typical autotransformer style unun. Adding a Nooelec 9:1 balun (being used as an unun) increased signal levels some due to a better impedance match, but did not help the signal/noise ratio at all. I find it does not work that well – largely, I think, due to noise. Information on the original can be found at : Īfter dragging out my Sears-branded Yeasu FRG-7 shortwave receiver, I strung up a “random wire” antenna. Note: Information on the original design (c) 2013 by Beric Dunn, K6BEZ, is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported.
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