Zepp antenna theory. Double Extended Zepp Antenna

FM is nearly an "all or nothing" modulation, either full-quieting signal or not very useful, and digital modes are even more so. Navy airship USS Macon was a foot dirigible. Similarly, electrical signals travel slower along an electrical conductor a little slower than light travels through a vacuum, depending on the dielectric constant of the surrounding material. This form of antenna originated as a practical solution to feeding a wire antenna trailing behind a dirigible. The model below, which could be a Zepp or J-pole, includes the feed line:. The velocity factor for Ethernet cable is even lower. The second source, in wire 5, is set for zero amperes.

 

The Half-Wave Zepp is an end-fed half-wave antenna. The very common dipole antenna is a half-wave wire that is broken at the center for connection to the feedline.This table uses a velocity factor of 0.

 

A Hawaii-based Amateur Radio Antenna Blog focusing on the theory, design, and use of homemade antennas. Search.In this video from AC2RJ, we see how some well-placed trees, a camera tripod, a telescoping fiberglass mast, and a "V" antenna can get you on the air without a lot of effort.

 

An excellent tutorial on the theory, construction, and use of the popular Zepp (or Zeppline) antenna. Stan Gibilisco (W1GV) does a good job.For higher bands it could be copper tubing, or even large-diameter wire.Forum Zepp antenna theory

 

In the Zepp or J-pole antenna is actually 3/4 wave long, with the counterpoise folded back alongside the radiating element. Make no mistake about it, no matter.By this antenna began to be used for land-based transmitters with the radiating element and the matching section mounted vertically, giving it the shape of the letter "J", [3] and was named the J antenna by

 

radiating half-wave section is mounted horizontally, at right-angles to the quarter-wave matching stub, the variation is usually called a Zepp antenna.Voltage difference is

 

97K subscribers in the amateurradio community. Welcome to Reddit's own amateur (ham) radio club. If you are wondering what Amateur Radio is about.The rule is: Current flowing into the antenna's end must be equaled, at that end point, by the same amount of current flowing into a ground or counterpoise of some type.

 

Zepp antenna. [′zep an‚ten·ə]. (electromagnetism). Horizontal antenna which is a multiple of a half-wavelength long and.The quarter-wave matching section would be about 17 cm or 6.

 

The double extended Zepp is a dipole type Antenna consisting of two collinear wave length elements fed in phase. This double extended version provides 3 db.Thank you for visiting my Amateur Radio Blog.

 

July 15,

 

It does not show normal differential mode non-radiating transmission line currents.

 

The feed point attachment will be the limiting factor as you move higher in frequency.

 

New York: McGraw-Hill.

 

An end-fed antenna must have something attached to the feedpoint that carries the same common-mode current away from the feedpoint as current flowing out onto the antenna!

 

Often the real world is much worse than a model, and rarely is it as good as a model.

 

Close the ends of the sections with pipe caps.

 

They also did not check voltage balance, which is just as important for preventing near field problems like RF in the shack.

 

This is why many authors conclude feed line radiation is not a problem, and I agree for this specific perfect case!

 

In the Zepp antenna system, or any end fed half wave, this displacement current must get back to the feed line somehow.Forum Zepp antenna theory

 

As Stan suggests, you can get multiband performance of this antenna by using ohm ladder line or ohm television twin lead to feed signals to a balun and an antenna transmatch i.

 

Unfortunately, a good pattern does not mean the system's feed line is properly balanced.

 

This means, lacking a proper counterpoise and common mode isolation, an accidental and generally unwanted feed line or mast common-mode current must exist.

 

Pattern alone does not prove proper feeder operation, and balanced currents at one point do not prove freedom from feeder radiation.

 

The project is straight forward, simple, and gives you emergency communications while you peddle down the road.

 

The Half-Wave Zepp is an end-fed half-wave antenna.

 

It means the antenna might not be repeatable or reliable, or have the pattern or performance expected, as a better planned system would have.

 

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See : Straw, Dean

 

Twin-lead isn't as common as it was when everyone with a television had an antenna, because TV was all terrestrial broadcast.

 

Close the ends of the sections with pipe caps.

 

When measuring the wire it is very important to get each of the two sides as close to the same length as possible.

 

To have a non-radiating feed line, the balanced feed line must have exactly equal and opposite currents and voltages at the feedpoint and all along the line.

 

Close the ends of the sections with pipe caps.

 

With an end-fed, current flowing from the stub or feeder out into the end of the radiator must be returned to the opposing conductor of the feed line.

 

Retrieved 4 March

 

In this video from AC2RJ, we see how some well-placed trees, a camera tripod, a telescoping fiberglass mast, and a "V" antenna can get you on the air without a lot of effort.

 

The volts is very manageable from a tuner, and it won't matter much if the tuner uses a good voltage balun, or a good current balun.

 

An end-fed antenna must have something attached to the feedpoint that carries the same common-mode current away from the feedpoint as current flowing out onto the antenna!

 

Make no mistake about it, no matter how we feed the antenna or how painstakingly we tune the antenna or stub, the "stub" or feed line will always radiate.

 

forum? A loop with turns should be enough at VHF frequencies.