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> Electronics > Remove category: Antennas and Accessories

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Items: 1 - 15 of 111 | Pages: 1  2  3  4  5  6  7  8  Next 
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  • Shakespeare Low-profile VHF Marine Band Antennas 5240 and 5241R heavy duty

    Shakespeare Low-Profile VHF Marine Band Antennas

    Shakespeare low-profile VHF marine band antennas are perfect choice for bassboats, center consoles,...

    In Stock 

    Price: $88.18 to $91.46
  • Flexible Rubber AM/FM Radio Antennas

    Rubber AM/FM Marine Radio Antennas

    Flexible rubber AM/FM radio antennas will improve your boat's radio reception. 16 1/1in length,...

    Price: $13.71
  • Shakespeare Magnetic Mount VHF Antenna

    Shakespeare Magnetic Mount VHF Antenna

    This small, stainless steel whip antenna features a magnetic mount, for fast and easy attachment to...

    In Stock 

    Price: $47.06
  • Shakespeare Standard Male VHF Connectors

    Shakespeare Standard Coaxial VHF Connectors

    Shakespeare connectors for VHF radios and coaxial cables. Each connector is gold plated to resist...

    In Stock 

    Price: $13.80 to $16.09
  • CableClam Sealed Thru-Deck Connectors

    Blue Sea Systems CableClam Sealed Thru-Deck Connectors

    CableClam Sealed Thru-Deck Connectors provide a waterproof cable installation without the need to...

    In Stock 

    Price: $15.58 to $25.25
  • Jensen Marine Amplified AM/FM Antenna

    Jensen Marine Amplified AM/FM Antenna

    Jensen Marine amplified antennas provide increased signal range for your boat's AM/FM radio. The...

    In Stock 

    Price: $19.83
  • UHF fittings for coaxial cables

    UHF Coaxial Cable Connectors

    Ancor UHF coaxial cable fittings are available in Crimp-On, Twist-On, Reducing Adapters, Solder-On,...

    In Stock 

    Price: $5.74 to $11.12
  • Shakespeare PL-259-CP-G Centerpin Solderless Connector

    Shakespeare PL-259-CP-G Centerpin Solderless Connector

    The Shakespeare PL-259-CP-G centerpin solderless connector connects RG-58 A/U, or RG-8/X coaxial...

    In Stock 

    Price: $16.06
  • Shakespeare ART-3 VHF Radio and Antenna Tester Meter TX-RX

    Shakespeare ART-3 VHF Radio and Antenna Tester

    The Shakespeare ART-3 VHF Radio and Antenna Tester is the only meter in its class to test receiver...

    In Stock 

    Price: $164.41
  • Metz Manta-6 Marine VHF Antenna

    Metz Manta 6 Marine VHF Antenna

    The Metz Communications Manta-6 marine VHF antenna provides minimal resistance. This compact VHF...

    In Stock 

    Price: $13.04 to $34.75
  • Shakespeare 5206-N 8 ft VHF Marine Band Antenna with nylon ferrule

    Shakespeare 5206-N 8 ft VHF Marine Band Antenna

    Shakespeare 5206-N 8 ft VHF Marine Band Antenna is economical, lightweight, and self-supporting....

    In Stock 

    Price: $53.42
  • Whitecap VHF Antenna Connectors

    Whitecap VHF Antenna Connectors

    Whitecap offers a variety of VHF antenna connectors for VHF marine radios. Various styles...

    Price: $4.00 to $8.96
  • Ancor Coaxial Cable

    Ancor Coaxial Cable

    Ancor Coaxial Cable is made from premium tinned copper for up to 50% less signal loss than other...

    In Stock 

    Price: $88.74 to $373.06
  • Shakespeare 4357 AM/FM/VHF Band Signal Separator

    Shakespeare 4357 AM/FM/VHF Band Separator

    The Shakespeare 4357 S AM/FM/VHF Marine Band Separator eliminates the need for separate AM/FM...

    In Stock 

    Price: $74.83
  • Shakespeare Phase III VHF Antenna

    Shakespeare Phase III VHF Antenna

    The Shakespeare Phase III 4' antenna features heavy-duty construction around the incomparable Phase...

    In Stock 

    Price: $229.21 to $303.69
Items: 1 - 15 of 111 | Pages: 1  2  3  4  5  6  7  8  Next 
 

Antennas

VHF, SSB Marine radio, Satcom, satellite radio, GPS, Loran, cellular phones and satellite TV, what do all of these electronics have in common? Marine radio navigation and communication devices are the most sophisticated and complex in the world. But all depend entirely upon clear reception of radiowave frequencies, without reception they won't function. Therefore, whenever installing high grade radio navigation or radio communication electronics, the foremost priority should be a quality marine antenna optimized for receiving signals in that frequency range.

What difference will a good antenna make? No matter how much you spend on a marine radio, performance relies ultimately on the quality and performance capabilities of it's antenna. Here are some basic considerations for commonly used marine electronics.

Antenna Height

For line of sight transmission such as VHF radios, antenna height is paramount. Mounting an antenna of adequate length at the best possible height assures the furthest range along the curvature of Earth. (Information based on Geographic Range Table calculations in Coast Pilot. i.e. 5 ft above sea level has line of sight of 2.6nm, 10 ft height has a range of 3.7nm.) As a general rule, sailboats typically mount a 3-5ft antenna on top of the mast. This mounting elevation offers superior range of communication. Racing sailboats sometimes opt to mount an 8 ft antenna on the stern as a fail safe against dismasting at sea. Powerboats up to 25 feet in length typically install a standard 8 ft antenna, while bigger vessels may require a larger antenna with higher gain. The other limiting range factor is power of transmission, but standard radios are most often limited by geographic range before power becomes a consideration. In US waters, transmission power is also regulated by the FCC.

Gain

Gain, measured in decibels (dB), rates communicating range. In general the higher the gain, the further the transmission will carry. The compromise of a higher gain is a narrower signal beam. This compressed beam can cause weak or intermittent signals in a rolling sea. For smaller boats prone to excessive roll, the gain used does not exceed 6dB. Larger, more stable vessels can effectively use a higher gain. Shakespeare antennas offer a low angle radiation which maintains a normal beam width consistent with gain, but has a lower trajectory for more power across the horizon. Low angle radiation doesn't suffer as much weak signal strength in heavy seas.

Mounts

Mount style is dependent upon the needs of the boat. Many boats require a fold down antenna mount to pass under bridges or for trailering. In such a case, be sure the installation site allows enough room for the antenna to lay down. If using two-piece antenna systems, an upper support clamp is necessary. Be sure to check with the antenna manufacturer for the appropriate mount setup to allow flex without damage to the antenna.

Cable

Cable selection depends upon the length of the cable run. For VHF, HF/SSB, and cellular communications, the optimum is the shortest possible cable run. For cable runs feeding marine radios of up to 20 ft, RG-58 cable is sufficient. For cable runs in excess of 20 feet, the recommended cable size is the larger and better, low loss RG-8/X, RG-8A/U or RG-213. Some antenna manufacturers offer a low loss cable engineered specifically for the needs of dual band cellular communications. These cables have the higher conductive characteristics of RG-8A/U and RG-213 cables without the bulk.

Radio Navigation - GPS, Loran C, RADAR

The Federal Navigation Plan

"The ideal navigation system should provide three things to the user. First, it should be as accurate as necessary for the job it is expected to do. Second, it should be available 100% of the time, in all weather, at any time of day or night. Third, it should have 1005 integrity, warning the user and shutting itself down when not operating properly. The mix of navigation systems in the US is carefully chosen to provide maximum accuracy, availability, and integrity to all users, marine, aeronautical, and terrestrial, within the constraints of budget and practicality.

"The Federal Radionavigation Plan (FRP) is produced by the U.S. Departments of Defense and Transportation. It establishes government policy on the mix of electronic navigation systems, ensuring consideration of national interests and efficient use of resources..."
American Practical Navigator, Bowditch.


As electronic navigation has advanced over the years, many systems have phased out in favor of modern improvements. Many systems have become active or defunct through the policy of the Federal government and the FRP. Radiobeacon signals were once the primary navigation aids during the first half of the 20th century. They are no longer in use today. Loran C, which is accurate to as far as 2000 miles offshore, is slated to be discontinued in the indefinite future, but still remains current because of a large number of users. Today, GPS has become the tool of choice for electronic navigation.

There are two principal types of GPS devices available on the consumer market, the Wide Area Augmentation System (WAAS) and Differential GPS (DGPS). The difference is algorithms within the device to correct for accuracy. DGPS is the type used in commercial and military marine navigation, WAAS is more prevalent in terrestrial use. Antennas for GPS are required for units installed in wheel houses and used in cars. The GPS signal is filtered out by modern windshields and enclosures. This necessitates installation of short antenna run to open skies.



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