9:1 Balun For End Fed Antenna

A 9:1 Balun For Your End Fed Antenna

End-Fed antennas do have their place in radio and other communications work. Like everything else, antennas come in many forms and flavors. It’s up to the designer to select the best design for the job at hand and to utilize that design in the most efficient way.
* * * A Bad Rap? * * *
– End-Fed antennas are NOT balanced systems; but neither are verticals, ground planes, discones, windoms, zepps, Marconis, half-slopers, et al. Additionally, the low-impedance antenna port of your transmitter/receiver is not balanced.
– End-Fed antennas are noise magnets. Really? That’s because most hams and SWL-ers don’t bother to interface them properly.
– End-Fed antennas have wild impedance swings. So do all antennas, but not at the design frequency – there, at the design frequency, the terminal impedance is quite predictable.
To make the best use of an End-Fed antenna, it should be fed with a transformer. Here are some photos of one of my 9:1 baluns. However, when using it with an End-Fed antenna it is wired as a (so-called) “unun” transformer (unbalanced to unbalanced). The raw End-Fed antenna will go through impedance swings as high as 5K Ohms, or more, at even multiples of its 1/4 wavelength design frequency. At every odd multiple it will be at a more civil impedance of between 36 and 90 Ohms. Using the transformer, the magnitude of the impedance swings is greatly reduced. This is due, in part, to the ratio balancing of the transformer’s turns (windings), and to a few complex reactance and other physics attributes that I won’t try to cover here. Additionally, the unun will eliminate (virtually) all “common mode” currents on the feedline. This is important for eliminating the pickup of local electrical noise from homes and power distribution lines. The coax, being connected to ground through a DC path will eliminate all but the differential currents … pretty cool, huh? Finally, since the antenna is connected directly to Earth ground through the secondary of the transformer, static buildup cannot occur – the antenna is a dead (DC) short to ground. This is important to sensitive, solid state radios.
The 9:1 transformer provides: 1. a much flatter broadband impedance response, 2. a static elctricity-free antenna system (no buildup), 3. common mode noise immunity (if space wound as shown).

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How to become HAM Radio Operator

Any individual above the age of 12 can became a ham radio operator in India after qualifying in Amateur Station Operators Certificate examination conducted by “The Officer-In-Charge”, WPC, Wireless Planning Commission, Government of India, Department of Telecommunication under Ministry of Communication through monitoring station which have their office in various states / cities in India.

These days it has become very to take HAM Radio exam. It takes just a week to train oneself to become eligible for the examination. Also here are many clubs stations in India which keep preparing for the ham radio license test and keep conducing these exams from time to time.

Amateur radio or ham radio is practiced by more than 16,000 licensed users in India. The first amateur radio operator was licensed in 1921, and by the mid-1930s, there were around 20 amateur radio operators in IndiaAmateur radio operators played an important part in the Indian independence movement

What is Amateur Radio / HAM Radio

Amateur Radio (ham radio) is a popular hobby and service that brings people, electronics and communication together. People use ham radio to talk across town, around the world, or even into space, all without the Internet or cell phones. It’s fun, social, educational, and can be a lifeline during natural disaster like floods, hurricanes, tornadoes, volcanic eruptions, earthquakes, tsunamis, and other geologic processes when all communications like cell phone, internet are down then the role of Amateur Radio comes into the picture.

HAM Radio a slang word is commonly used in this hobby.  It is sometimes claimed that HAM came from the first letter from the last names of three radio pioneers: Heinrich Rudolf Hertz, Edwin Armstrong and Guglielmo Marconi.

This hobby enjoyed by several hundred thousand people in the United States and by over a million people worldwide. Amateur radio operators call themselves “radio hams” or simply “hams.”