Category: Helical antenna design tutorial

Print this Post. Every few hours a NOAA weather satellite passes over your head, continuously transmitting pictures in visible light, infrared, and shortwave infrared. Meteorologists utilize this information to predict weather. The good news is, so can you.

With something like the NooElec SDR dongle, a computer, and a QHF antenna you can predict your own weather, even if all other forms of communication are not functioning.

Why do I need to build such a complex looking piece of machinery? No, seriously, it has to do with simple physics and the nature of radio. Here is a simple explanation- Antennas perform best when they are properly polarized, or the antennas are pointed in the same direction in three dimensional space.

If you were to take two walkie talkies and point one antenna straight up and one sideways at a 90 degree angle you would notice that the reception would be severely degraded or nonexistent, even if in the same room.

helical antenna design tutorial

When you have a satellite orbiting the earth, even if the antenna is pointed straight down, its polarization to you on earth will change as it goes from horizon to horizon. The solution is to build an antenna that is properly polarized in all directions, hence the QFH antenna. What do I need to build the QHF antenna?

There are many ways to build this antenna and many tutorials can be found when scouring the web. They tell you what is needed for the antenna, but are a little short on how to put it together. The reason I chose this antenna was its rugged design, performance, and when you are done, it looks like a work of art.

To build this antenna you will need to be mechanically inclined and willing to dedicate a weekend to the project. Most of the materials can be purchased from any home improvement store, but here is the shopping list. These were hard to find in the local HI store, Lowes had them, but you can get them online here.

You will be cutting off one end. Remember, I built my antenna using this design and using this tutorial. My intention is to tell you HOW I did it. The very first thing you are going to have to do is prepare the PVC section of pipe. I arbitrarily picked 3 feet for total size. For the top of the antenna you are going to have to drill 4 holes at right angles to one another. This will require you to make two templates, one for the top of the pipe and one for the bottom.

Your templates should look something like this. I took a sheet of paper and cut out a 40mm wide strip.Antennas List Antenna Theory Home. Helix antennas also commonly called helical antennas have a very distinctive shape, as can be seen in the following picture. Photo of the Helix Antenna courtesy of Dr. Lee Boyce. The most popular helical antenna helix is a travelling wave antenna in the shape of a corkscrew that produces radiation along the axis of the helix antenna.

These helix antennas are referred to as axial-mode helical antennas.

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The benefits of this helix antenna is it has a wide bandwidth, is easily constructed, has a real input impedance, and can produce circularly polarized fields. The basic geometry of the helix antenna shown in Figure 1. Figure 1. Geometry of Helical Antenna. The parameters of the helix antenna are defined below.

D - Diameter of a turn on the helix antenna. S - Vertical separation between turns for helical antenna. The antenna in Figure 1 is a left handed helix antenna, because if you curl your fingers on your left hand around the helix your thumb would point up also, the waves emitted from this helix antenna are Left Hand Circularly Polarized.

If the helix antenna was wound the other way, it would be a right handed helical antenna. The design of helical antennas is primarily based on empirical results, and the fundamental equations will be presented here. The helix antenna is a travelling wave antenna, which means the current travels along the antenna and the phase varies continuously. In addition, the input impedance is primarly real and can be approximated in Ohms by: The helix antenna functions well for pitch angles between 12 and 14 degrees.

Typically, the pitch angle is taken as 13 degrees. The normalized radiation pattern for the E-field components are given by: For circular polarization, the orthogonal components of the E-field must be 90 degrees out of phase.

This occurs in directions near the axis z-axis in Figure 1 of the helix. The axial ratio for helix antennas decreases as the number of loops N is added, and can be approximated by: The gain of the helix antenna can be approximated by: In the above, c is the speed of light.

Note that for a given helix geometry specified in terms of C, S, Nthe gain increases with frequency. For the same example helix antenna, the pattern is shown in Figure 2.

Figure 2. Normalized radiation pattern for helical antenna dB. The Half-Power Beamwidth for helical antennas can be approximated in degrees by: Antennas List Antenna Tutorial Home This page on helix antennas helical antennas is copyrighted. No portion can be reproduced except by permission from the author.

Copyright antenna-theory.Helical antenna is an example of wire antenna and itself forms the shape of a helix. The frequency range of operation of helical antenna is around 30MHz to 3GHz. Helical antenna or helix antenna is the antenna in which the conducting wire is wound in helical shape and connected to the ground plate with a feeder line.

It is the simplest antenna, which provides circularly polarized waves. It is used in extra-terrestrial communications in which satellite relays etc. The above image shows a helical antenna system, which is used for satellite communications.

These antennas require wider outdoor space. It consists of a helix of thick copper wire or tubing wound in the shape of a screw thread used as an antenna in conjunction with a flat metal plate called a ground plate.

One end of the helix is connected to the center conductor of the cable and the outer conductor is connected to the ground plate. The radiation of helical antenna depends on the diameter of helix, the turn spacing and the pitch angle. Pitch angle is the angle between a line tangent to the helix wire and plane normal to the helix axis. In normal mode of radiation, the radiation field is normal to the helix axis.

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The radiated waves are circularly polarized. This mode of radiation is obtained if the dimensions of helix are small compared to the wavelength. The radiation pattern of this helical antenna is a combination of short dipole and loop antenna. It depends upon the values of diameter of helix, D and its turn spacing, S. Drawbacks of this mode of operation are low radiation efficiency and narrow bandwidth.

Hence, it is hardly used. In axial mode of radiation, the radiation is in the end-fire direction along the helical axis and the waves are circularly or nearly circularly polarized. The radiation pattern is broad and directional along the axial beam producing minor lobes at oblique angles.

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If this antenna is designed for right-handed circularly polarized waves, then it will not receive left-handed circularly polarized waves and vice versa. This mode of operation is generated with great ease and is more practically used.

helical antenna design tutorial

Antenna Theory - Helical Advertisements. Previous Page. Next Page.

LoRa/LoRaWAN tutorial 45: Normal Mode Helical Antenna

Previous Page Print Page.A Helical Antenna is formed of a helix shaped conductor wire. Normally a ground plane holds the helical antenna vertically and the antenna is technically fed like a monopole.

Helical antennas can operate in one of two principal modes: normal mode or axial mode. The following helical antenna is designed using the multi-configuration feature of HFWorks and operates at 2. A helix antenna consists of more than three turns of alumina or copper wire of a constant pitch.

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This sort of radiation is found in television and satellite communications as it has a higher capacity to struggle against losses caused by the atmosphere. Such an antenna emitting in a circular polarization has always a 3 dB power loss factor PLF with another linear polarized antenna.

Within this HFWorks tutorial, we introduce the key features of simulating a helix antenna. To simulate the behavior of this helix antenna we are more interested in radiation patterns and antenna parameters like gain, directivity In an antenna simulation, radiation boundaries which are peculiar features of such a simulation have to be assigned to the radiation surfaces. These surfaces truncate the air surrounding the antenna and simulate and anechoic chamber.

The helix which is the most important and special part of the antenna assembly is usually made of copper or aluminum. The conductivity of this metal imposes a certain direction to the electric field.

The latter is in this way polarized in circularly like pattern inheriting the form of the helix. The solid beneath the helix should be assigned a PEC Perfect Electric Conductor boundary condition to play the role of the ground metal. This can be automatically done realized by assigning the solid a PEC material from the material browser. As mentioned earlier, we have to define the radiation boundaries to truncate the open air space surrounding the antenna.

Antenna Theory Tutorial

The locations of these boundaries define the truncations for the air surrounding the antenna. The port definition for this antenna is located on a round surface beneath the ground metal, similarly to a connector for a coaxial cable. The helix goes through the cylinder until the port surface. The most important part of the antenna lies in the form of the helical conductor, the latter has to be meshed in a convenient rate to ensure reliable Maxwell's equations solution: The more you mesh a round shape, the more the solver realizes it is; nevertheless this shouldn't exceed a certain limit.

On the other hand the Teflon cylinder which has the wire signal going through its round cut should also be meshed in a fine rate. We obtain a mesh similar to this figure's:. Various 3D and 2D plots are available to exploit, depending on the nature of the task and on which feature the user is interested in.

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As we are dealing with an antenna simulation, plotting the radiation diagram seems like an intuitive task. The following figure shows the radiation pattern of the considered antenna:. This figure shows conformal views 2D and 3D of the variation of the power radiation pattern of the antenna in terms of the Theta angle.

As mentioned within the beginning of this report, HFWorks computes Scattering Parameters within antenna studies as well; this is mostly relevant to antennas' matching optimization tasks.

In this example, the antenna is best matched at 2. The polar plots for the antenna parameters cover a wide range of parameters: radiated electric field, radiation intensity, directivity, gain pattern, axial ratio This is a vector plot of the electric field at 2.

Helical Antenna Design.Until 2017, they were replaced with repeats of old music video blocks (namely BET Music, The Pull Up and BET Now). Since November 17, 2015. In 2007, a distribution deal was arranged with Paramount Home Entertainment. As a result, BET heavily censors suggestive content from the videos that it airs, often with entire verses and scenes removed from certain rap videos.

The BET website streamed the funeral live, while the channel periodically broadcast taped, 60-second reports from the funeral by senior news correspondent Andre Showell. Michael Lewellen, BET's senior vice president for corporate communications, defended the decision: "We weighed a number of different options. In the end, we chose to offer a different kind of experience for BET viewers.

Coates and his organization Enough is Enough led protests every weekend outside the residences of BET executives against what they claim are negative stereotypes of black people perpetuated by BET music videos.

I suggest to my kids that they don't watch it," she said. We had public affairs programming.

helical antenna design tutorial

I had a show called Teen Summit, we had a large variety of programming, but the problem is that then the video revolution started up. And then something started happening, and I didn't like it at all. And I remember during those days we would sit up and watch these videos and decide which ones were going on and which ones were not. We got a lot of backlash from recording artists. I didn't like the way women were being portrayed in these videos.

The program contained mature content, including highly sexualized imagery. Because of its content, the show was rated TV-MA and accompanied by an on-air message stating that it is not suitable for children under the age of 17. The show aired on Wednesdays through Fridays at 3 a.

Though some of the videos were from well-known hip hop artists, most were from lesser-known artists, and the production value of the videos was often quite poor. From Wikipedia, the free encyclopedia Jump to: navigation, searchFor other uses, see Bet.

TV by the Numbers. Retrieved February 24, 2015. Retrieved June 29, 2016. Archived from the original on September 12, 2008. Retrieved July 2, 2010. Retrieved December 30, 2010. Retrieved 4 December 2014. Archived from the original on 2011-08-16. Retrieved 15 October 2017.

helical antenna design tutorial

Archived from the original on 2011-09-09. Archived from the original on 2011-07-11. Archived from the original on 2006-05-06. Archived from the original on 2003-03-20. Archived from the original on March 3, 2010.

Archived from the original on 2011-07-14. Greenberg Charles Phillips Sumner Redstone (Chairman Emeritus) Shari Redstone William Schwartz BET BET Gospel BET Her BET Hip-Hop BET Jams BET Soul CMT CMT Music Comedy Central Comedy Central Extra Logo TV MTV MTV2 MTVU RateMyProfessors.

African-American televisionBET NetworksEnglish-language television stations in the United StatesMusic video networks in the United StatesMedia companies based in Washington, D. Greenberg Charles Phillips Sumner Redstone (Chairman Emeritus) Shari Redstone William Schwartz BET Networks BET BET Gospel BET Her BET Hip-Hop BET Jams BET Soul CMT CMT Music Comedy Central Comedy Central Extra Logo TV MTV MTV2 MTVU RateMyProfessors.

NickMusic Nicktoons Noggin TeenNick Nickelodeon Animation Studio Nickelodeon on Sunset. Erica Ash has some news for you.However, this will help you strengthen your bond with your colleagues.

Put all your energies in doing something you love. The day is good for indulging in recreational activities or hobbies. However, refrain from over-spending. Few of you may meet someone special today. Monetary gain from an unexpected source is foreseen. Also, your health should be of prime importance to you. A hearty chat with your spouse will lighten your day.

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However, be aware of the terms and conditions and check the documents carefully. You may have to chase people to get your work done today, but everything will fall into place by the end.

Some of you may spend money on the long-pending house renovation. Manchester United suffered their first defeat of the season last weekend - but could they lose more ground on Premier League leaders Manchester City when they face in-form Tottenham on Saturday. BBC Sport football expert Mark Lawrenson says: "United flunked at Huddersfield and, as bad as Liverpool were at Wembley, Tottenham played very well to beat them 4-1.

They rolled over in the first half against the Terriers but there is no way Jose Mourinho is going to let Spurs beat his side at Old Trafford. Lawro scored 70 points in week nine, which saw him slip to 3,152nd place out of more than 240,000 users.

Lawro, who beat Joe Root last week, takes on two of his England cricket team-mates for this weekend's fixtures - all-rounder Moeen Ali and bowler James Anderson. Burnley fan Anderson predicts a 1-0 win for his side at home to Newcastle on Monday and is hopeful the club can keep hold of manager Sean Dyche, who has been linked with the Everton job.

Remember you can try to beat Lawro by playing the BBC Sport Predictor game. Last week, Lawro got four correct results, including one perfect scores, from 10 matches, for a total of 70 points. He beat England cricket captain Joe Root, who got five results correct but with no perfect scores, for a total of 50 points. For this day's fixtures we have 433 matches from 85 leagues. All Match time is in your local timezone()Premium will get you more wins.

Plus, you get Corner stats and Card stats along with CSV. Premium will get you more wins. We also provide analysis for in-play statistics, which will inform you at which point in a match a team scores or concedes their goals across the season. This feature is handy for understanding in-play dynamics of each football team. Be sure also to check out our latest football tips, selected using our data and stats, as well as enjoying a read of our football blog.

We have over 300 data points per league, team, and players. Yes that's right - three whole hundred data points. It's quite overwhelming at first but here are some of the most used datas : Over 0. The possibilities with these data are endless. We even have odds so that you can compare them against the stats at a glance to see if they provide value. We make every single one of these data public through our API and CSVs which will be available later this year.

We encourage you to use our data to do your own soccer stats analysis such as machine learning and model based predictions. Shots and posession data will be available later this year as well. Other stats services update once a week, or once a day. We update within 10 minutes of matches ending and our users love us for it.If tout services knew their customers were winning, the smart choice would be the one-time deposit, instead of one tied to losing.

The oddsmaker said he has never seen touts choose the deposit. After the Donaghy scandal, Bell and Johnny Detroit tried to make Pregame. So they funneled their sportsbook referrals through Canadian-registered Pregame Action, a go-between which may have provided a way around a U.

Two months before Pregame Action went missing, Johnny Detroit left. Johnny Detroit apparently recuperated quickly. There were rumors on sports betting forums that he and Karalis had asked to share in the affiliate spoils, but were rejected by Bell.

Helical Antenna Design Calculator

Neither do I personally. It did not mention Pregame Action or Sharpbettor. He declined multiple times to answer those questions, instead issuing a statement that did not address them. After this story was published, he emailed me, denying involvement with Pregame Action and Sharpbettor.

The bettor whose livelihood is dependent on having an edge can only be so helpful. If enough people get a whiff, the value is gone.

It is counterintuitive that anyone good enough at betting sports to make money on it would ever publicize his picks, no matter the price.

Maybe Americans would like to believe that successful sports bettors resemble average joes more closely than they do the mathematicians, financial analysts, statisticians, and software developers who actually do this for a living.

The real bettors, like Jacob Wheatley-Schaller, offer fewer absolutes, and less interesting soundbites. It makes for great radio when Fezzik calls out his three-star game of the year, but far less exciting when a bettor explains that he bet three-quarters of a percent of his bankroll based on his perceived edge against the closing line.

And if revenge were a computable variable, bookmakers would have already factored it into the line. For poker magazine All In, he looked at more than 200 public handicappers and found that not one had a lifetime win rate of 55 percent. The data showed that only about five percent of these touts could achieve a lifetime win rate of 52.

Not much has changed since then, except now the hundreds of touts out there have a wider audience for their questionable logic. In a low-budget 2013 documentary on sports betting called Life on the Line, a group of sad-looking touts known as the Tuesday Group meet to discuss their ideas before the 2011 Super Bowl.

I saw Tiger Woods get humbled, I saw Brett Favre get humbled, I think Roethlisberger on the biggest stage of the world is gonna get humbled. Later in the film, Covers mocks a young bettor for not being able to show him a spreadsheet of his allegedly excellent results. This explains why Bell almost never mentions Fezzik without including his past glory: back-to-back NFL contest wins from 2008 and 2009.

In recent months, Bell has circled the wagons around Fezzik, his flagship pick-seller. Eichenlaub wrote that he found several errors in its grading and record-keeping early on, when Johnny Detroit was in charge of the records.

Bet Like a Pro was, according to Pregame, up 26 units year-to-date when Eichenlaub stepped in on August 7, 2015. Since then, it has taken a 14-unit loss.

With Johnny Detroit and Jeff Scott Sports everything was fine, then Bob tracks and everything goes to crap.

Bell encouraged his customers to buy subscriptions and not daily selections, thus bringing down the cost of each pick. My personal picks are also monitored daily by an independent documenter. Plus, a dedicated Pregame forum thread is prominent for anyone to report any pick grading or win streak mistakes, ensuring that necessary corrections are publicly made.

No other pick selling site even comes close. A few months ago, four apparently clandestine recordings of a meeting purporting to be between Bell and his touts were posted online. Did Deadspin confirm authenticity. Did Deadspin demand to hear the full context. A person purported to be Fezzik says average bettors are picking at 50 percent on their own, but after paying for a pick from a tout, they might win 53 percent of the time.

Say you only buy three picks a week, three packages a week.


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