N7DDC (CGJ-100) antenna tuner tuned 43 feet wire from 160m to 10 m in my backyard! Field review.

N7DDC automatic antenna tuner is popular among the portable operators due to its small size (~120X70X30 mm) and 100W handling capability. There is a great variety of this tuner implementations starting from the cheap kits finishing with fully assembled units. The CGJ-100 incarnation of this tuner is sold by the Chinese ham BH8CGJ. In difference from some other Chinese or Russian sellers this one is equipt with 3 function buttons (all models have these foreseen in the circuit but not all sellers/manufacturers take an attempt to actually install them) also a switch on/off button and has got an installed 4000mAh battery pack and USB C connector for charging. In my other video (https://youtu.be/cD_WZ65MZ_k) I evaluated the quality of how this tuner was made and how to look for and fix faults.
This video is about the actual work of the tuner. It has been tested in my backyard (due to corona lockdown and movement restrictions in my location I can't go to other field-testing places) using a 43' wire as a Random Wire Antenna plus the ~9m radial on the ground. Not all random wires make a good antenna. There are "good" and "bad" lengths. Good are those which are NOT a 1/2 wavelength or its multiples on any of ham radio bands. These non-resonant antennas have an impedance of few hundred ohms across all amateur bands and are easy to tune with the antenna tuner usually combined with the 9:1 UNUN. The "bad" lengths are those of 1/2 w/l or multiple because of their impedance is very high reaching up to several thousand ohms. Such antennas could only be tuned with special sort of impedance transformers (49:1 or 64:1). In no way this means that being of "bad" length for a random wire antenna it is a bad an antenna! EFHW (End Fed Half Wave) antennas make a whole separate class of antennas and are extremely popular and effective. But in this video I stick to a random wire antenna as more simple , compact and versatile and best combined with this type of antenna tuners. There is lots of good information about the 'good -bad" random wire antennas on this site including concrete tables and dimensions to choose from.
http://www.hamuniverse.com/randomwireantennalengths.html
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Attributions:
SFX used in this video:
www.freesound.org/people/Tomlija
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73! CUL! Linas LY2H

Видео N7DDC (CGJ-100) antenna tuner tuned 43 feet wire from 160m to 10 m in my backyard! Field review. канала LY2H Ham Radio Van