Is AJ pole directional?
The J-pole antenna, more properly known as the J antenna, is a vertical omnidirectional transmitting antenna used in the shortwave frequency bands.
What is Super J pole antenna?
The Super J Pole antenna is a co-linear vertical consisting of a number of half wave length vertical elements separated with half-wave length stubs (Tuning stub) feed with a folded matching stub. The sub doesn’t receive or radiate any energy; it is simply a way of picking off the desired feed impedance.
What is the gain of a Slim Jim antenna?
Slim Jim antennas have no performance advantage over the conventional J-pole antenna. The approximate gain in the H-plane of the Slim Jim is from 1.5 to 2.6 dBi (-0.6 dBd to 0.5 dBd).
How good is a Slim Jim antenna?
The Slim Jim is probably one of the cheapest and easiest antennas to make, and it’s a very handy one too. You can typically make one of these for under £10, they roll up easily for storage and travel, and are great for use at home, or when travelling, for accessing local repeaters.
Do J-pole antennas have gain?
The J-pole antenna is an end-fed omnidirectional half-wave antenna that is matched to the feedline by a quarter wave parallel transmission line stub (Lecher line). Being a half-wave antenna, it provides a small gain over a quarter-wave ground-plane antenna.
How big is a 2 meter J pole?
Here are the plans to build a 2 meter J-pole antenna: The above dimensions for the J-pole are in inches. Measurements on overall length, and stub length are from the centerline of the separation pipe (horizontal) to the top of the antenna.
How big is a J pole tuning stub?
The distance between the main element of the j-pole centerline and the tuning stub centerline is 2″. I cut a length of RG-8X foam coax to a length of 67″ for the feedline, and coil up 4 turns (as small as you can get it) just below the horizontal part of the matching section.
What kind of antenna is a J pole?
The j-pole antenna is basically an end fed half wave dipole that uses a 1/4 wave shorted matching stub as an impedance transformer. The j-pole antenna will yield slightly less than 3 DB of gain omnidirectionally. The material I chose to build the j-pole antenna was 3/4 inch copper pipe used for plumbing.
Can A J pole be soldered to a copper pole?
See Fig 1. The entire assembly can be soldered together when copper is used, thus ensuring electrical in- tegrity, and making the whole antenna weatherproof in the bargain. I’ll bet you could solder one of these to- gether faster than using the nuts and bolts I did in my previous design.
