Arduino antenna tuner12/7/2023 Where 192.168.0.14 will be your computer IP address, rotctld will listen on port 4533 for rotator commands from gpredict. To start the process, besides having the the Arduino rotator controller you need to start rotctld similar to: Here only appending the decimal point and works correctly on gpredict 2.0-4. See "0.0" appended, that sends 10x more angle, else gpredict will receive angle/10 Since I've seen some posts with similar issues here's what I got while testing regarding behaviour: Now works fine on both implementations in Linux. Long story short I ended up starting my own code, half way trough discovered what looks like a different implementation or Eas圜omm II protocol on hamlib in Linux depending on version.Īt some point trough my code I reverted to do changes on YO3RAK code to accommodate my setup, a mix of hamlib 1.2.15.3 and 3.1 along with gpredict 1.3 and 2.0-4. Googling around for some Arduino controller code I found from fellow ham YO3RAK at: Ĭompiled it along with some LCD library changes and noted that was not fully working with rotctld (Hamlib 1.2.15.3) and gredict (1.3) on Linux. You will find a suitable design on PD7MAA's website (Ref-4).I have an unused TV aerial rotator and would be good to put it, along with an motorized elevation control, for some satellite work. You could opt for a simple led tuning indicator. There are many possible SWR meter circuits. Of course, as most of you will also want to use your tuner in transmit mode, I am including information to incorporate a SWR indicator for QRP power levels in the tuner. Since my homebrew antenna tuner was meant to be used primarily in receive mode, with an experimental end-fed antenna, I intended to use my trusted antenna analyzer to help me find preliminary capacitor settings on each band below 15 MHz. They did not have the amount of capacitance that I needed for my project.Īfter browsing around the Web for a few hours, I found what I was looking for at Peebles Originals (Ref-3): two dual-gang variable capacitors (approximately 500 pf per section). I rummaged through my junk box(es) but only found two old units that I had extracted from superhet receivers some decades ago. Next I had to find two dual-section air variable capacitors. Furthermore, I wanted the tuner to help me experiment with my many oddball home-brewed HF antennas! I intended to design my homebrew antenna tuner to suit my specific antenna system situation, instead of using a more "universal" design which is a "one-size-fits-all" device normally intended to be useful in "most" circumstances, but generally only with reasonably well-designed HF antennas. The drawback was that their higher "Q" meant that one could not deal with as large a range of antenna system impedances and operating frequencies as one can with a T-network. I learned that, much like L-networks, the efficiency of link-coupled networks was much greater than the popular T-networks. ![]() While reading the many articles that were published on the Web and amateur radio books, I was discovering that they had a lower parts count and, in some instances, were less complex to build while remaining capable of transforming a fair range of impedances down/up to 50 ohms - which is the nominal input/output impedance of HF transceivers and amplifiers. Link-coupled network: this is where things got interesting. I published a short summary of my preliminary findings on tuners in my ebook on HF antenna accessories (see ref.1 below). I studied the most popular antenna tuner networks in search of the best set of compromises for my purposes. And sacrificing as little as possible in performance!.I also wanted the tuner to be easily reproducible. ![]() Specifically, I was hoping that my homebrew antenna tuner would improve my signal to noise ratio on the aforementioned bands. My goal was to see if I could improve reception on the lower frequency amateur radio bands such as on 160 meters (1.8-2.0 MHz), 80 meters (3.5-4.0 MHz) and 40 meters (7.0 - 7.3 MHz). ![]() Below is the network design that I settled on for my first attempt. The QS1R SDR receiver probably does not need this much pampering to perform exceptionally well, but I was curious nonetheless. Best Of Breed The Z-Match The FRI-Match My Experiment A Tuning Indicator Transmatch Explained T vs L-Networks T-Networks L-Networks References
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