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 baruwww.dxengineering.com

  Vertical antenna
• 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 barufr.m.wikipedia.org

  Loop antenna
• 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 barum0ukd.com

  Ground-plane antenna
• 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 barupalomar-engineers.com

  Terminated antenna

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.

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

Payment via Paypal

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.