How long should a VHF antenna be?
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. Additionally, height is always an important factor.
What type of antenna does VHF use?
VHF antennas are made of stainless steel or fiberglass. For masthead mounting, short 3dB stainless steel “whip” antennas create less windage and provide the appropriate wide radiation pattern required by a heeling sailboat. Small powerboats may also use stainless whip antennas because they are rugged.
Which VHF antenna is best?
Best Marine VHF Antennas
| Best Marine VHF Antennas | Rating |
|---|---|
| 1. Shakespeare 5226-XT 8′ Galaxy Antenna | 99% |
| 2. Shakespeare 5101 Centennial White 8′ VHF Marine Antenna | 96% |
| 3. Tram 1607-HC 46-Inch VHF Marine Antenna | 93% |
| 4. Shakespeare 5104 4′ Centennial VHF Antenna | 89% |
Does a VHF antenna need to be vertical?
Your VHF antenna attached to the AIS device needs to be as high as possible and as far away as possible from other vertical metal objects. Vertical metal objects include other vertical antennas, sailboat masts, radar masts, stays, bimini frames and any other lengths of metal parallel to the antenna.
What is the most common type of antenna for VHF?
vertical whip
The most common type of GMDSS VHF antenna is a vertical whip….
- The shore or on-board antenna must be vertically polarized.
- The antenna array must be type-accepted for 30-200 MHz operation by the FCC.
- The horizontally-polarized antenna must be positioned so as not to cause excessive interference to other stations.
What is the best material for antenna?
Copper is a best suited material for base antennas. The metal, while soft and malleable, is quite rigid. Stainless steel has a higher tensile strength, so thinner wire can be used.
What is the electrical length of a VHF antenna?
Turns out that the most efficient electrical lengths are somewhat shorter than the electromagnetic wave’s physical crest-to-crest length. VHF Marine antennas typically use 1/4 wavelength, 1/2 wavelength, and 5/8th wavelength ratios. A 1/4 wave antenna then would be an antenna with an electrical length one-fourth…
What kind of antenna do you need for a VHF boat?
While there are several types of antennas available for VHF Marine use, we will concentrate on the 8ft vertical whip, since it is by far the most common. If there is one thing standard about VHF 8ft whip antennas; its the fact that there is no “standard” antenna.
How tall is the center of the VHF radio frequency?
If you could measure the electromagnetic wave with a yardstick at 156.725 Mhz, which is the frequency at the center of the VHF Marine band, it would be about 1.92 Meters from “crest” to “crest”.
What’s the frequency of a VHF marine radio?
VHF Marine radios operate from 156.025Mhz to 157.425Mhz, which is often known as the “2 Meter Band”. If you could measure the electromagnetic wave with a yardstick at 156.725 Mhz, which is the frequency at the center of the VHF Marine band, it would be about 1.92 Meters from “crest” to “crest”.