What is the gain of a J pole antenna?
Gain and radiation pattern 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).
What is the gain of a 2 meter J pole antenna?
about 3 db
Average gain with a 2 meter J-Pole is about 3 db. Many like to compare the gain and antenna pattern to that of a Ringo Ranger. The biggest advantage of the J-Pole is that it is at DC ground, so it can be mounted just about anywhere and still work.
Do you need to ground J pole antenna?
As for the second half of the question: yes the J-Pole should be grounded. But instead of an RF ground, the antenna should have an electrical ground to protect it in case of a lightning strike.
How long should a 10 meter antenna be?
Read more about . . . . Dipole Length Calculations.
| Approximate Lengths for HF Ham Band Dipole Antennas | ||
|---|---|---|
| Band (MHz) | Length (Feet) | Length (metres) |
| 21.00 (15 metres) | 22.8 | 7.04 |
| 24.89 | 19.3 | 5.94 |
| 28.00 (10 metres) | 17.1 | 5.28 |
Should I ground my J-pole antenna?
What is a J pole antenna?
The J-pole antenna is an end-fed omnidirectional half-wave antenna that is matched to the feedline by a shorted quarter-wave parallel transmission line stub. A half-wave antenna fed at one end has a current node at its feedpoint, giving it a very high input impedance of around 1000–4000 Ω.
Why Measure J antennas?
Measurements reveal the effects of common mode current on the J antenna. Learning more about several ferrite compositions from the Fair-Rite manufacturer including where to buy them. I measure one example of a ferrite coax choke for response over frequency to understand its suitability for VHF and UHF.
How do you feed A J pole antenna?
The J-pole antenna and its variations may be fed with balanced line. A coax feed line may be used if it includes a means to suppress feed-line RF currents. The feed-point of the J-pole is somewhere between the closed low-impedance bottom and open high-impedance top of the J stub.
What are the characteristics 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).