VHF (Very High Frequency) antennas are an important part of the VHF system used on your boat. They’re made to receive signals that are between 30-300 MHz, and these signals degrade less than UFH (Ultra-High Frequency) signals, allowing them to have a longer broadcast range.VHF (Very High FrequencyVery High FrequencyVery high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter.https://en.wikipedia.org › wiki › Very_high_frequency
Very high frequency – Wikipedia
) antennas are an important part of the VHF system used on your boat. They’re made to receive signals that are between 30-300 MHz, and these signals degrade less than UFH (Ultra-High Frequency) signals, allowing them to have a longer broadcast range.
What are the long antennas on boats for?
The broad radiation pattern from a low dB antenna allows a sailboat to heel over and still send signals toward the horizon. Sailboats should use a 3dB antenna mounted at the top of the mast whenever possible.
Why do some boats have 2 VHF antennas?
The advantages of the dual antenna Not only does the installation of a second antenna give better readability to the AIS signal, but it can also serve as an emergency antenna for VHF. Just allow enough length behind the unit to disconnect the antenna from the AIS and connect it to the VHF.
What is a marine antenna?
The term marine antenna refers to antennas connected to certain on-board devices so that they can receive and/or propagate radio waves.
How long is a marine VHF antenna?
A 3- to 4-foot antenna that’s 3 dB is generally recommended for boats under 24 feet. Larger vessels can opt for 12- to 18-foot, 7 to 8 dB antennas. “As a general rule, antenna height should be less than half the length of the boat,” Catoe says.
Is longer antenna better?
The higher the wavelength, the longer the antenna needs to be to match it properly, and the wavelength is inversely proportional to the frequency. 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.
How long should my VHF antenna be?
The wavelength of a signal should always be 1/4 the length of the antenna you’re using, as this gives you the very best efficiency. While you don’t have to pick an antenna whose length is exactly 4 times the wavelength of the signal, it’s a good idea to get as close as you possible can.
What is UHF VHF antenna?
VHF antennas and UHF antennas use very high frequency (VHF) and ultra-high frequency (UHF) signals for two-way radio, public safety, and commercial communications. VHF is the range of radio frequency (RF) signals from 30 to 300 MHz. UHF is the range between 300 MHz and 3 GHz.
What does VHF stand for?
VHF, in full very high frequency, conventionally defined portion of the electromagnetic spectrum including any radiation with a wavelength between 1 and 10 metres and a frequency between 300 and 30 megahertz. VHF signals are widely employed for television and radio transmissions.
Do I need a separate AIS antenna?
If you have a transponder you must use a splitter designed specifically for use with AIS transponders. However, your VHF antenna may not be well tuned at AIS frequencies which will lead to poor transmit performance. Using a splitter also means you can’t transmit on your VHF and receive AIS updates at the same time.
What are VHF antennas?
VHF (Very High Frequency) antennas are an important part of the VHF system used on your boat. They’re made to receive signals that are between 30-300 MHz, and these signals degrade less than UFH (Ultra-High Frequency) signals, allowing them to have a longer broadcast range.
What is 3db antenna?
The term Antenna Gain describes how much power is transmitted in the direction of peak radiation to that of an isotropic source. Similarly, a receive antenna with a gain of 3 dB in a particular direction would receive 3 dB more power than a lossless isotropic antenna.
Do marine VHF antennas wear out?
The antennas do not actually ever “go bad” however just like everything they are susceptible to water damage. If yours is sealed and has no signs of corrosion it will be fine. All that is inside of them is a wire of the proper wave length, keep it dry and it will last forever.
What is antenna length?
An antenna – usually 1/2 wavelength long – split at the exact center for connection to a feed line. Dipoles are the most common wire antenna. Length is equal to 1/2 of the wavelength for the frequency of operation. We often refer to antenna size relative to wavelength.
Which VHF antenna is best?
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.
What is the frequency range of VHF?
Radio frequency range from 30 MHz to 299 MHz. The sub-bands most commonly used by fire are: VHF-FM Lo band: Frequency Modulation 30 MHz – 80 MHz, of which fire frequencies are between 30 MHz and 50 MHz.
Is a long antenna better than a short antenna?
Longer antenna elements are resonate at lower frequencies. Shorter antennas are resonate at higher frequencies. There are ways to combine elements to make them resonate a different frequencies.
Does bigger antenna mean better reception?
A bigger antenna, properly designed, will always have more gain than a smaller one. And it will be the best kind of gain, much better than using a small antenna and simply overamplifying it, because a small antenna just won’t pull in truly weak signals like this gigantic one will.
How is antenna length determined?
The length of the antenna is inversely proportional to the frequency and directly proportional to the wavelength. The higher the frequency and the shorter the wavelength, the shorter the antenna can be made.