For Low Z at home I will build another ATU. It was nice to experiment with, but to be honest I think I will just keep the High Z part for portable work. If I adjust it to work well for High Z, it won’t work well on Low Z… and the other way around. That is because it doesn’t seem to perform well in both cases. Fixed capacitors, switched with relays in 256 steps, 3 pF per step, from 3 to 800 pF. ![]() Convert the balanced line to an unbalanced line Either system is subject to limitations. Web a balanced balanced antenna tuner qst february 1990, pp. A toroid is only used in the 1:1 balun on the TX side. This simple tuner can properly match anything from a bedspring to a long. Connect a dummy load to the BYPASS (4) connector using a coax cable. The circuit consists of 2x each of the following: Fixed inductors, switched with relays in 128 steps, 0.25 uH per step, from 0.25 to 32 uH. If using a single wire antenna, connect it to post (7) without installing jumper. So far I can say that having both High Z and Low Z in one tuner with limited capacity and inductance is not that great. If you are using a balanced feed antenna, connect a balanced line to the BALANCED OUTPUT connectors and jumper banana jack (8) with lower jack (7) as shown by dotted line. But well built it has chances to be really useful. ![]() As I was saying, I just wanted to experiment with and see how it performs. Once this ATU will perform as I wish it should be and I am happy about it, I will try to think of a PCB design that will help you build it really quick and compact with not many wires all over the place. These days I tested it a little more and down bellow you also have the comparison test video I made, between the ATU and the 49:1 impedance transformer. I tried tuning random wires with or with ought a counterpoise. Before receiving my nanoVNA, the only tests I could make were using the built in LED SWR meter.
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