How long should a doublet antenna be?
The Antenna: The antenna proper consists of a length of copper or copperweld wire, with a center feedpoint. Three popular lengths for the antenna are these: a. 130-140′ (best, if you have the room and want the strongest results on 80 meters.
What is 300 ohm cable?
300 ohm twin lead is widely used to connect FM radios to their antennas, and was previously used to connect television antennas to televisions until it was replaced by coaxial cable.
Is a dipole antenna 75 ohm?
A dipole has an impedance of 75 ohms. A folded dipole has an impedance of 300 ohms. If you want to match a dipole (75 ohms) to a 75 ohm cable (typical cable TV coax), then you don’t need a matching transformer.
Is a doublet a dipole?
The doublet antenna is a form of dipole operated with balanced feeder, typically open wire feeder and used with a tuning unit to provide multiband operation. The doublet antenna is a form of dipole that uses a balanced feeder, often open wire feeder and an antenna tuning unit.
What is a folded dipole?
A folded dipole is an antenna, with two conductors connected on both sides, and folded to form a cylindrical closed shape, to which feed is given at the center. Hence, it is called as half wave folded dipole antenna. The directivity of Folded dipole Antenna is bi-directional. The input impedance is higher.
Can you use coax cable for antenna?
There are three types of cable in general use for FM antennas. One is the flat 300-ohm twin- lead cable that has been in use for decades. The second and more popular type is RG59/U 75- ohm coaxial cable. The typical line loss of RG59/U is about 3dB per 100ft at 100MHz.
How do you connect twin leads to coaxial cable?
Using coaxial wire, plug one end into the “Out To TV (RF)” port on the Converter Box. Plug the other end into the coaxial port on the coaxial adaptor. Then attach the twin-lead output of the coaxial adaptor to your TV “Antenna In” twin-lead terminals.
Is a G5RV any good?
The performance is very good across the HF bands and requires little or no tuning. By moving the feedpoint away from the center and adding a 4:1 or 6:1 balun, you can cover a number of HF bands. Although some claim the popular G5RV antenna works well on all bands, 80 through 10 meters, that is not the case.
Does a G5RV need a choke?
A balun or choke should NOT be used on a G5RV wire dipole. The classic G5RV 102 ft. wire dipole consists of 51 ft. legs with a center feed of twin lead or ladder line that is about 31 ft.
What’s the difference between a 75 ohm and a 300 ohm FM antenna?
I’d say the most significant difference between the two is convenience. You see, 75 OHM coax can be a lot easier to use when compared to the 300 OHM cable. Plus, most modern receivers come with 75 OHM cable connections. A standard dipole offers 75 OHM of balanced impedance, which is another thing to consider.
What is a Windom antenna?
The Windom antenna is an off-center fed dipole with an unbalanced coax feedline. In 1937, the Windom was first described as a compromise multiband antenna. The antenna can be employed on 80, 40, 20 and 10m with considerable, though acceptable levels of VSWR.
Can a 2 meter HT be used as an emergency antenna?
In an emergency situation, it is often necessary to squeeze every bit of performance possible out of a 2 meter HT. One way to do that is to replace that little rubber duck antenna with the ever-popular Twinlead J-Pole. This simple antenna lends itself well to emergency use or as a portable antenna for hotel room operations while traveling.
What kind of lead is a J pole antenna made of?
A short article describing the construction of an emergency j-pole antenna made from 300 ohm TV twin lead. The Twinlead J-Pole Craig LaBarge, WB3GCK
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:
What’s the best way to hang a J pole antenna?
To facilitate hanging, punch a small hole in the top of the antenna. Use monofilament fishing line or other non-conductive line through the hole for hanging. The J-Pole is very broad-banded, so it shouldn’t require any tuning.