What size antenna do I need for my boat?
What size antenna do I need for my boat?
For a powerboat under 24 feet or a sailboat, a 3 dB antenna is recommended. Usually a 6 dB antenna is recommended for boats over 24 feet and a 9 dB antenna is recommended for boats over 32 feet. Longer antennas generally have higher dB ratings but check the technical specifications of the antenna to be sure.
How long should my marine antenna be?
“As a general rule, antenna height should be less than half the length of the boat,” Catoe says. Higher-dB antennas generate greater effective radiated power, and that can translate into greater range.
What is beamwidth of omnidirectional antenna?
Beamwidth is the angle from which the majority of the antenna’s power, as illustrated on the radiation pattern’s main lobe, radiates. It may be horizontal (azimuth) or vertical (elevation) or in the case of omni-directional antennas around 360 degrees horizontally.
Is longer antenna better?
In a nutshell, the longer the antenna the more signals it can catch. So for your truck trying to catch the wavelengths of your radio station, typically what is referred to as a quarter-length antenna is best, so that’s about 32 inches long.
How far can marine VHF radio transmit?
Your VHF radio is intended mainly for short range communications, generally 5-10 miles, and at least 20 miles to a USCG station. To communicate at longer ranges, you will normally need a satellite telephone or an MF/HF marine radiotelephone.
How is antenna gain measured?
* Antenna gain is measured in decibels as either dBi or dBd. dBi refers to dB away from a theoretical isotropic antenna (0), while dBd refers to dB away from a more real world reference dipole antenna with a gain of 2.15 dB. A theoretical perfectly spherical coverage pattern measured in dBd would be -2.15 dBd.
How far apart do VHF antennas need to be?
A good rule is to keep antennas at least 1/2 wavelength apart or at least 3ft at VHF and even at that spacing the radiation pattern may look like a clover leaf with good signal going out in four directions and lousy performance in between the clover leaf pattern.
What is angular width of antenna?
The antenna beamwidth is the angular width expressed in degrees which is measured on the major lobe of the radiation pattern of an antenna. HPBW: The angular width on the major lobe of radiation pattern between two points where the power is half of the maximum radiated power is called Half Power Beam-width.
What is directional gain?
Gain: The difference in signal strength achieved by an antenna is known as gain, which is measured in decibels (dB). Directional antennas adjust the gain pattern to better receive signals from a specific direction.
Does the size of an antenna matter?
So the answer is yes, size does matter, but bigger isn’t always better. It all depends on what your transmitting and receiving frequencies are. Theoretically, a longer antenna will have a greater range, but it is far more important for optimal radio performance that the length of the antenna matches the frequency.
