Is a J-pole directional?
Unsourced material may be challenged and removed. The J-pole antenna, more properly known as the J antenna, is a vertical omnidirectional transmitting antenna used in the shortwave frequency bands.
Who is Ed Fong?
Ed Fong, WB6IQN – “The DBJ-1 Antenna“. As many of you know, he is the inventor of the DBJ-1 and DBJ-2 antenna that was featured in the February 2003 and March 2007 QST. His latest article in QST was the TBJ-1 – a triband base antenna published in March 2017.
What is the gain of AJ 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).
How does a Slim Jim antenna work?
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. It can be built for almost any frequency!
Do you need to ground J-pole antenna?
J-Pole antennas are half wave antennas by design. Actually they are a half wave antenna sitting on top of a quarter wave matching section. One great advantage of a half wave antenna that it doesn’t require any special grounding or a ground plane to operate.
Are J-Pole antennas any good?
Member. 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.
Does a Slim Jim antenna need to be grounded?
Interestingly this page says that for the Slim Jim, no part should be grounded and it should be insulated from its mast.
Is a Slim Jim antenna omnidirectional?
How do you ground a J-pole antenna?
A simple electrical ground would consist of a ground line from the antenna either bonded to the tower system or run to a buried ground rod. The lack of a groundplane makes it easy to mount this antenna just about anywhere. You could put it in your attic, on a chimney or a temporary mast.