Is J-Pole a good antenna?
The myth is that j-poles have lots of gain and are better than anything else. A j-pole is just a 1/2 wave end fed antenna fed with a 1/4 wave transmission line matching section. If constructed and tuned properly, they only have as much gain (0 dBd) as a dipole.
What is the gain of a J-pole antenna?
Primarily a dipole, the J-pole antenna exhibits a mostly omnidirectional pattern in the horizontal (H) plane with an average free-space gain near 2.2 dBi (0.1 dBd).
Do you need to ground J-pole antenna?
J-Pole antennas are half wave antennas by design. But instead of an RF ground, the antenna should have an electrical ground to protect it in case of a lightning strike. An electrical ground doesn’t enhance the RF radiation of the antenna, but it is an important safety feature on any installation.
What is a Slim Jim antenna?
The Slim Jim Antenna. The Slim Jim is a vertically polarized omnidirectional end-fed antenna having considerable “gain” and this is concentrated almost parallel to ground toward the horizon rather than skyward making it more efficient than a ground plane type antenna by about 50 percent better.
Is a J pole antenna balanced or unbalanced?
The J-pole is a good example of a poorly implemented feed system, because it mixes balanced and unbalanced systems. In the J-pole, an unbalanced end-fed half wave radiator is fed by a balanced 1/4 wave stub. The balanced stub is fed by unbalanced coaxial cable.
Is higher antenna gain better?
If you want to focus all of the signal to direct it to a distant target, then the high gain antenna is definitely the best choice. High gain antennas need to be pointed in a preferred direction to send RF signal so that limited signal can be intensified in desired location, as illustrated below.
How do you ground a Jpole?
hammer the top of the rod with a 5 pound hammer or small sledge hammer. As the rod is driven down, you may need to descend the ladder for the best angle to drive it. Once the rod is within a few inches of the ground, you can stop.
What is the best J pole antenna for VHF?
A Dual Band VHF/UHF J Pole – This antenna provides continuous coverage of the 2 metre (144-148MHz) and 70cm (430-450MHz) bands and is an excellent choice for base station use. Build a Weatherproof PVC JPole Antenna – After you have build this antenna, you may not need anything else.
How much does A J-pole antenna cost?
Homemade 2M/440 J-Pole Antenna – A 2m 70cm Dual Band J-Pole antenna for 35 USD. An excellent performing J-Pole type antenna, constructed from readily available materials.
Which J-pole should I Choose?
A Dual Band VHF/UHF J Pole – This antenna provides continuous coverage of the 2 metre (144-148MHz) and 70cm (430-450MHz) bands and is an excellent choice for base station use. Concealed DSS J-Pole – The idea here is to have my antenna high in the air, in free space, with the dish mounted close by for concealment.
What is J-pole theory pop?
J-Pole theory pop – The J-Pole antenna is an omnidirectional antenna that can be used for base, mobile and field day stations. It does not need a ground plane, radials or a complicated matching system. The J-Pole can be cheaply, simply and quickly constructed using a variety of techniques, some of which are discussed in this article.