Antenna Handbook

Dual Band J Pole Antenna

Dual band J-pole antenna:

A dual band J-pole antenna is a type of antenna that can be used to transmit and receive radio waves on two different frequencies. It is made up of two parallel wires that are fed at a point that is one-quarter wavelength from each end. The length of the wires is determined by the frequencies that the antenna is designed to operate in.

The two wires in a dual band J-pole antenna are typically spaced apart by a quarter wavelength. This helps to ensure that the antenna is resonant and that it radiates efficiently on both frequencies.

Dual band J-pole antennas are typically used for amateur radio applications, but they can also be used for other applications, such as public safety communications and wireless networking. They are a good choice for these applications because they are relatively easy to build and install, and they offer good performance.

Here are some of the key features of a dual band J-pole antenna:

It can be used to transmit and receive radio waves on two different frequencies.
It is relatively easy to build and install.
It offers good performance on both frequencies.
It is a versatile antenna that can be used for a variety of applications.

Here are some of the applications of a dual band J-pole antenna:

Amateur radio
Public safety communications
Wireless networking
CB radio
Ham radio
Two-way radio

To design a dual band J-pole antenna, you will need to know the frequencies that you want the antenna to operate in. The formula for calculating the length of the wires is:

length = wavelength / 2

where:

length is the length of the wire in meters
wavelength is the wavelength of the radio waves in meters

For example, the wavelength of radio waves at 145 MHz is 1.995 meters. So, for a dual band J-pole antenna that is designed to operate on 145 MHz and 440 MHz, the length of the wires would be 0.9975 meters and 0.49875 meters, respectively.

Once you know the length of the wires, you can start designing the antenna. The two wires can be made of any type of metal, but copper is a good choice. The wires should be mounted on a mast or tower that is at least as tall as the length of the wires.

The two wires should be spaced apart by a quarter wavelength. This helps to ensure that the antenna is resonant and that it radiates efficiently on both frequencies.

The dual band J-pole antenna can be fed with either a balanced or unbalanced signal. A balanced signal is required for the best performance, but an unbalanced signal can also be used.

If you are considering designing a dual band J-pole antenna, I recommend that you consult with an antenna engineer to ensure that you choose the right antenna for your needs.

Here are some additional details about the design of dual band J-pole antennas:

The length of the wires can be adjusted to tune the antenna to the desired frequencies.
The two wires can be made of different materials to improve the performance of the antenna.
The two wires can be bent or folded to improve the radiation pattern of the antenna.

The design of a dual band J-pole antenna can be complex, and there are many factors to consider. If you are not familiar with antenna design, I recommend that you consult with an antenna engineer.

V Antenna

Here is an image of a V antenna:

www.tutorialspoint.com

A V antenna is a type of dipole antenna that is made up of two long wires that are arranged in a V-shape. The two wires are fed with a balun, which is a device that converts between a balanced and unbalanced signal.

V antennas are typically used for medium to high frequency applications, such as amateur radio, FM broadcasting, and public safety communications. They are a good choice for these applications because they are relatively easy to build and install, and they offer good performance.

The length of the wires in a V antenna is determined by the frequency it is designed to operate in. The formula for calculating the length of the wires is:

length = wavelength / 2

where:

length is the length of the wire in meters
wavelength is the wavelength of the radio waves in meters

For example, the wavelength of radio waves at 145 MHz is 1.995 meters. So, for a V antenna with a frequency of 145 MHz, the length of the wires would be 0.9975 meters.

The height of the V antenna can also affect its performance. A higher antenna will have a better radiation pattern, but it will also be more susceptible to interference from objects on the ground.

V antennas are a versatile and effective type of antenna that can be used for a variety of applications. They are relatively easy to build and install, and they offer good performance.

V Antenna Design Calculator

V antenna design calculator:

Frequency (MHz): 145
Height (m): 10

Element length (m): 5.263157894736842

This calculator calculates the length of the elements of a V antenna for a given frequency and height. The formula used is:

length = wavelength / 2

where:

length is the length of the element in meters
wavelength is the wavelength of the radio waves in meters

The wavelength of the radio waves can be calculated using the formula:

wavelength = c / frequency

where:

c is the speed of light in meters per second
frequency is the frequency of the radio waves in hertz

For example, the wavelength of radio waves at 145 MHz is:

wavelength = c / frequency = 299,792,458 m/s / 145 MHz = 1.995 m

So, for a V antenna with a frequency of 145 MHz and a height of 10 meters, the length of the elements would be:

Element length = 0.9975 m

This calculator is just a simple example, and there are many other factors that can affect the length of the elements of a V antenna. For more accurate results, you should consult a qualified antenna engineer.

Here are some of the factors that can affect the length of the elements of a V antenna:

The dielectric constant of the material the antenna is made of
The thickness of the antenna
The conductivity of the material the antenna is made of
The ground conductivity

If you are designing a V antenna for a specific application, it is important to consider all of these factors to ensure that the antenna will perform as expected.

Super J Antenna Calculator

Here is a Super J antenna calculator:

Frequency (MHz): 145
Feed point height (m): 1

Element 1 length (m): 0.7071067811865475
Element 2 length (m): 0.3535533905932737

This calculator calculates the length of the elements of a Super J antenna for a given frequency and feed point height. The formula used is:

length = wavelength / 2 - feed_point_height

where:

length is the length of the element in meters
wavelength is the wavelength of the radio waves in meters
feed_point_height is the height of the feed point of the antenna in meters

The wavelength of the radio waves can be calculated using the formula:

wavelength = c / frequency

where:

c is the speed of light in meters per second
frequency is the frequency of the radio waves in hertz

For example, the wavelength of radio waves at 145 MHz is:

wavelength = c / frequency = 299,792,458 m/s / 145 MHz = 2.046 m

So, for a Super J antenna with a frequency of 145 MHz and a feed point height of 1 meter, the lengths of the elements would be:

Element 1 length = 0.7071067811865475 m
Element 2 length = 0.3535533905932737 m

This calculator is just a simple example, and there are many other factors that can affect the length of the elements of a Super J antenna. For more accurate results, you should consult a qualified antenna engineer.

do-it-yourself j antennas for 145 MHz drawings

Here are some do-it-yourself J antennas for 145 MHz drawings:

J-pole antenna: A J-pole antenna is a simple and effective antenna that can be made from a few materials. It is a good option for beginners who are looking to build their own antenna.
Terbuka di jendela baru www.jpole-antenna.com

To make a J-pole antenna, you will need:

* A piece of wire that is 1/4 wavelength long at 145 MHz.
* A connector for your radio.
* A way to mount the antenna.

The wire can be any type of metal, but copper is a good choice. The length of the wire will depend on the frequency you are using. For 145 MHz, the wire should be about 25 inches long.

The connector can be a BNC connector, PL-259 connector, or any other connector that is compatible with your radio.

The antenna can be mounted on a mast, a wall, or any other suitable surface.

Terminated J-pole antenna: A terminated J-pole antenna is a variation of the J-pole antenna that has a resistor at the end of the antenna. The resistor helps to absorb the radio waves that are not transmitted or received by the antenna. This helps to prevent the antenna from radiating harmful interference.

To make a terminated J-pole antenna, you will need:

* A piece of wire that is 1/4 wavelength long at 145 MHz.
* A resistor that is rated for the power output of your radio.
* A connector for your radio.
* A way to mount the antenna.

The wire and resistor can be the same as for a standard J-pole antenna. The connector can be a BNC connector, PL-259 connector, or any other connector that is compatible with your radio.

The antenna can be mounted on a mast, a wall, or any other suitable surface.

Folded J-pole antenna: A folded J-pole antenna is a variation of the J-pole antenna that has a second piece of wire that is folded in half. The folded wire helps to improve the radiation pattern of the antenna.

To make a folded J-pole antenna, you will need:

* Two pieces of wire that are 1/4 wavelength long at 145 MHz.
* A connector for your radio.
* A way to mount the antenna.

The wires can be the same as for a standard J-pole antenna. The connector can be a BNC connector, PL-259 connector, or any other connector that is compatible with your radio.

The antenna can be mounted on a mast, a wall, or any other suitable surface.

These are just a few examples of do-it-yourself J antennas for 145 MHz. There are many other designs available, and you can experiment to find the one that works best for you.

It is important to note that building your own antenna can be a challenging project. If you are not comfortable working with electrical equipment, you should consult with a qualified amateur radio operator.

LW Antenna Design

A longwave (LW) antenna is an antenna that is designed to transmit or receive radio waves in the longwave band, which ranges from 150 to 525 kilohertz (kHz). LW antennas are typically large and cumbersome, as the wavelength of longwave radio waves is very long.

Here are some of the most common types of LW antennas:

Vertical antenna: A vertical antenna is the simplest type of LW antenna. It consists of a single vertical conductor, such as a metal rod or pipe. The length of the antenna should be one-quarter of the wavelength of the radio waves it is designed to transmit or receive.
Terbuka di jendela baru www.dxengineering.com
Loop antenna: A loop antenna is a circular or elliptical antenna. It is made up of a single conductor that is bent into a circle or ellipse. The diameter of the loop should be one-half of the wavelength of the radio waves it is designed to transmit or receive.
Terbuka di jendela baru fr.m.wikipedia.org
Ground-plane antenna: A ground-plane antenna is a vertical antenna that is surrounded by a ground plane. The ground plane is a conducting surface, such as a metal sheet or a network of wires, that is placed below the antenna. The ground plane helps to improve the radiation pattern of the antenna.
Terbuka di jendela baru m0ukd.com
Terminated antenna: A terminated antenna is an antenna that is terminated in a resistor. The resistor absorbs the radio waves that are not transmitted or received by the antenna. This helps to prevent the antenna from radiating harmful interference.
Terbuka di jendela baru palomar-engineers.com

The design of an LW antenna depends on a number of factors, including the frequency band it is designed to operate in, the desired radiation pattern, and the amount of space available.

If you are planning to build an LW antenna, it is important to consult with a qualified antenna engineer to ensure that the antenna is designed correctly.

Here are some of the things to consider when designing an LW antenna:

Frequency band: The frequency band that the antenna is designed to operate in will determine the length of the antenna.
Radiation pattern: The radiation pattern of an antenna describes how the radio waves are emitted from the antenna. There are many different radiation patterns that can be used for LW antennas.
Space available: The amount of space available will determine the size and shape of the antenna.
Cost: The cost of the antenna will depend on the materials used and the complexity of the design.

Once you have considered these factors, you can start designing your LW antenna. There are many resources available to help you design an antenna, such as books, websites, and software programs.

Quad Beam Loop Antenna Calculator

Cubical Quad Beam Loop Antenna is fullwave length Antenna, designed in the mid of 1940's , each side being a quarter wavelength, and fed at a current loop in the center of one side, the voltage loops occur in the middle of the adjacent sides — and that reduces or eliminates the arcing.

The background for the creation of the Cubic Quad Beam Antenna is due to the existence of shortwave radio stations located in the highlands. previously used a Yagi

antenna which is more suitable for lowland, to transmit worldwide with high voltage input, This antenna is fed in the middle of the current loop, so the end is the

high voltage loop. In the thin air of Quito, Ecuador,the high voltage at the tip causes a corona arc, and that arc periodically destroys the tip of the Yagi element.

so Design station engineer Clarence Moore designed Cubical Quad Beam antenna to solve this problem.

Fig 1. Quad Loop Antenna

Fig 2. Quad Loop Antenna

The antenna shown in Fig. 1 is actually a quad loop rather than a cubical quad. Two or more quad loops, only one of which needs to be fed by the coax, are used to make a cubical quad antenna. If only this one element is used, then the antenna will have a figure-8 azimuthal radiation pattern (similar to a dipole). The quad loop antenna is preferred by many people over a dipole for two reasons. First, the quad loop has a smaller "footprint" because it is only a quarter-wavelength on each side Fig 1. Second, the loop form makes it somewhat less susceptible to local electromagnetic interference (EMI).

The quad loop antenna (and the elements of a cubical quad beam) is mounted to spreaders connected to a square gusset plate. At one time, carpets were wrapped around

bamboo stalks, and those could be used for quad antennas. Those days are gone, however, and today it is necessary to buy fiberglass quad spreaders. A number of kits are advertised in the web.

The details for the gusset plate are shown in Fig.2 . The gusset plate is made of a strong insulating material such as fiberglass or in marine-grade plywood.

It is mounted to a support mast using two or three large U bolts (stainless steel to pre- vent corrosion). The spreaders are mounted to the gusset plate using somewhat smaller U bolts (again, use stainless steel U bolts to prevent corrosion damage)

Cubical Quad Beam Loop Antenna

The elements can be fed in the center of a horizontal side fig A, in the center of a vertical side fig B , or at the corner fig C

There is a running controversy regarding how the antenna compares with other beam antennas, particularly the Yagi. Some experts claim that the cubical quad has a gain

of about 1.5 to 2 dB higher than a Yagi (with a comparable boom length be- tween the two elements) . In addition, some experts claim that the quad has a lower angle of radiation. Most experts agree that the quad seems to work better at low heights above the earth's surface, but the differencdisappears at heights greater than a half-wavelength.

The quad can be used as either a single-element antenna or in the form of a beam. Figure Fig 3. shows a pair of elements spaced 0.13 to 0.22 wavelengths apart. One element is the driven element, and it is connected to the coaxial-cable feedline directly. The other element is a reflector, so it is a bit longer than the driven element. A tuning stub is used to adjust the reflector loop to resonance.

Because the wire is arranged into a square loop, one wavelength long, the actual length varies from the naturally resonant length by about 3 percent. The driven element is about 3 percent longer than the natural resonant point. The overall lengths of the wire elements are :

1. Driven element : L = 1005/F [MHZ] ft

2. Reflector : L = 1030/F [MHZ] ft

3. Director : L = 975/F [MHZ] ft

with Shortwave Frequency range : 3 - 30 MHz, Center Frequency F[MHZ] = 16.5 MHZ.

Quad Beam Cubical Antenna Calculator login form

Input Center Frequency (in MHz) for Quad Beam Loop Antenna

Quad Beam Loop Antenna Calculator

Input Center Frequency

Driven Element in ft
Reflector in ft
Director in ft

One method for the construction of the quad beam antenna is shown in Fig. 4. This particular scheme uses a 12 x 12-in wooden plate at the center, bamboo (or fiberglass) spreaders, and a wooden (or metal) boom. The construc- tion must be heavy-duty in order to survive wind loads. For this reason, it is probbly a better solution to buy a quad kit consisting of the spreaders and the center structural element.

WiFi router antenna, modem antenna, 23cm 5M omni directional antenna

Sale WiFi router antenna, modem antenna, 23cm 5M omni directional antenna

Inquiry to hadisyarief@gmail.com

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Specification:

Frequency Range: 698-960MHZ, 1710-2700MH.

Gain: 12 dBi

VSWR: <2.5 Polarization

Type: Vertical or horizontal

Radiation: Omni

Maximum Imput power: 10W

Input Impedance: 50 Ohms

Cable Type: RG58 50-3 cable

Cable length: 10 Meter

Demensions: about 23cm 63*63mm

Horizontal Half Power Angle: 360°

Vertical Half Power Angle: 70 15°

Lightning Protection: DC Ground Working

Temperature: -40°C-65 C

Connector: SMA male

Wire Gauge Standard VS American Wire Gauge

Standard VS American Wire Gauge

SWG	Diameter (inch)	Nearest AWG
12	0.104	10
14	0.08	12
16	0.064	14
18	0.048	16
20	0.036	19
22	0.028	21
24	0.022	23
26	0.018	25
28	0.148	27
30	0.0124	28
32	0.0108	29
34	0.0092	31
36	0.0076	32
38	0.006	34
40	0.0048	36
42	0.004	38
44	0.0032	40
46	0.0024	--

Standard vs American Wire Gauge.

Antenna Insulators

Common materials that you can use for insulating hardware when building antennas. Homemade insulators are inexpensive. I encourage you to make them, especially for your dipoles.

High-quality insulators are mandatory for good performance. A half-wave dipole has very high RF voltage at the outer ends. This means that your end insulators must have a high dielectric factor (high breakdown voltage and infinite resistance). I suggest that you use insulators that are made from polyethy- lene rod or tubing (available from industrial plastic vendors). High-impact polystyrene rod or tubing is also good. Plexiglass T™) is also a good insulating material, but it is brittle and shatters easily, especially during cold weather. It is best to avoid this material for long dipoles. You should also avoid nylon insulators, as they may heat and burn when subject- ed to high RF voltage. PVC pipe and tubing is similarly poor in the presence of high RF voltage.

If you purchase commercially made insulators, try to obtain glazed porcelain ones. Another acceptable commercial insulator is made from molded polyethylene. Radio Shack stores. stock this type of end insulator. They are available also from farm stores that sell electric-fence components. Fig 4 shows how to fashion your own insulators from tubing and solid rod.

Fig 4 - Examples of homemade antenna insulators. The unit at A is made from solid plastic rod. Grooves may be cut at the ends, as shown, with a router. This relieves the stress on the antenna wire and helps to keep the wire from shifting position on the insulator. Suggested dimensions are given for developing a strong insulator. Example B shows how to make an insulator from plastic tubing. A rectangular plastic block (C) is also suitable as an insulator. Grooves can be added to the ends of this unit also.

If you are willing to spend additional money when building high quality homemade insulators, please consider the use of Delrin or Teflon rod. These materials are also available from industrial plastics dealers.

For short-term emergency situations you can make your dipole end insulators from 4-inch pieces of 3/4-inch dowel rod. Drill the holes in the wood, then boil the wooden insulators in canning wax for 10 minutes. The wax will impregnate the wood, which will prevent it from absorbing moisture and becoming lossy. Alternatively, you may soak the dowel-rod insulators in exterior polyurethane varnish for 24 hours. Allow them to dry thoroughly before using them.

Dipole Conductors

The general rule is to use wire for HF-band dipoles -- no. 12 or 14 being the most popular size. Aluminum tubing is used for HF, VHF and UHF Yagi antennas because this material is strong enough to be self-supporting. HF-band Yagis are equipped with elements that telescope. This reduces the overall weight by permitting us to use small-diameter tubing for the outer ends of the elements. The telescoping antenna elements also allow us to make easy adjustments when tuning the system for low SWR and maximum forward gain.

I suggest that you use stranded no. 14 copper wire for your HF-dipole elements. This wire is easily available and it does not cost a great deal of money. It is sufficiently flexible to endure under the stresses of wind and moderate icing, assum- ing it is supported properly. If the span of the dipole is greater than 130 feet, try to have a center support where the feed line is attached. RG-8 coaxial cable is quite heavy, and this places considerable stress on the dipole. RG-8X, on the other hand, is smaller and lighter, and may not cause too much stress at the center of the dipole. RG-8X will safely handle up to 1000 watts of RF power if the SWR on the line is less than 2:1. It is approximately the same diameter as 75-ohm RG-59 cable.

The Noise Bridge

There is another instrument that you may use for resonance tests. It is known as a noise bridge. It is connected between your receiver and the feed line to the antenna. Your antenna will be purely resistive at resonance, so the null in the noise from the bridge will be the deepest at the frequency of antenna resonance.

The reactance controls on the noise bridge will be at zero when this null occurs. The bridge will provide a resistance reading when fully nulled, and this will indicate not only antenna resonance, but allow you to read the feed-point impedance (resistive) of the antenna. In order for this instrument to be accurate, you must use an electrical half wavelength of coaxial feeder between the antenna and the bridge.

The instrument generates white noise, and this is heard in the receiver output (speaker of phones). The bridge controls are adjusted for minimum noise to indicate antenna resonance. You will need to tune your receiver to various frequencies in the ham band of interest in order to locate the resonant frequency of the antenna.

The noise bridge is readjusted for a null at each of these frequencies until you find a frequency that yields a deep null with the reactance controls at zero. This may seem complicated now, but if you study the operating booklet for your noise bridge, things will fall into place easily.

source : Novice Antenna Notebook by DeMaw, Doug