What is doublet in antenna?
The doublet antenna is a form of dipole that uses a balanced feeder, often open wire feeder and an antenna tuning unit. As open wire feeder is able to operate with levels of standing waves and effectively becomes part of the antenna, it is able to operate over a wide band of frequencies.
How efficient is a doublet antenna?
An efficient doublet should be at least 1/4λ to 1/3λ at the lowest operating frequency. A 3/8λ version has an efficiency greater than 98% relative to a λ/2 dipole and can have SWR values that are reasonably easy to match.
What is the length of ladder line?
Your dipole is cut for 40 meters or about 66 feet total length and you feed it with ladder line to a tuner to make it a multibander….
| 160 meter dipole | 35-60, 170-195 or 210-235 feet | (Avoid 130, 260 ft) |
|---|---|---|
| 40 meter dipole | 42-52, 73-83, 112-123 or 145-155 feet | (Avoid 32, 64, 96, 128 ft) |
What is a 1 1 balun?
Model BA-1-1500 is a 1:1 balun kit used to translate a 50 ohm unbalanced input to 50 ohms unbalanced at power levels up to 1500 watts PEP when used with a matched load. With a matched load the SWR will not exceed 1.5 over the frequency range 1.8 to 30 MHz.
How long is an 80-meter dipole?
Since an 80 meter dipole is approximately 130 feet long, and a 160 meter dipole is approximately 250 feet long, this space reduction can be critical in getting the antenna to fit into our typical backyards. Another often cited reason is that the inverted vee makes a better match to the typical 50 Ohm feed line.
How long is a G5RV JR antenna?
Standard G5RV antennas are 31 meters (102 feet) long, excluding feedline and matching section length, and can be used on 80, 40, 20, 15, and 10 meters. A half-length G5RV (51 feet long) can be used on 40, 20, 15, and 10 and is known as the G5RV Junior.
What is the impedance of ladder line?
Ladder line may also be manufactured or DIY-constructed as “open wire line” consisting of two parallel wires featuring widely spaced plastic or ceramic insulating bars and having a characteristic impedance of 600 ohms or more.
How to calculate the length of a dipole antenna?
The Half-Wave Dipole Antenna. The most widely used formula to calculate the approximate overall length of wire required for a dipole is: 468 / frequency (MHz) = length of wire in feet.
What is the all band HF doublet antenna?
The all band doublet antenna is nothing more than a 1/2 wave dipole cut for your lowest operating frequency and fed with twinlead, ladder line, open wire, etc to a tuner that will accept a balanced line connection. IT IS NOT FED WITH COAX! It can be designed for use from 160 thru 10 meters very easily using the standard 1/2 wave dipole formula:
How is a doublet different from a dipole?
Since the current does not follow the dipole pattern, the charge density is also different from a dipole. In this case, there are many transitions and the current is not maximum at the center feedpoint. The term doublet is more generic and less fully descriptive than others. However, it also has a history.
How to calculate the length of a half wave antenna?
The basic formula for determining the length of a center fed, half-wave wire Dipole or Inverted Vee antenna is: 468 ÷ freq (mHz) = Length (feet). This formula takes into consideration the capacitive “end-effect” from insulators which shortens the physical length requirement for the equivalent electrical length.