Technical Bulletins

References for the RF industry

Technical Sheets

"How-to's" on Shively products

Calculators

Presentations by Bob Surette

• "Shively Labs Meets the Very Windy Mountain"
  from May-June 2008 Radio Guide
• "Shively Labs: Antennas That Work!"
  from September 2007 Radio Guide [279 kB]
• "Shively 6014 Dual Hybrid Antenna Solves a Dilemma"
  from September 2007 Radio Guide [232 kB]
• Vermont Public Radio's Mt. Mansfield Project (October '06)
• West Virginia Public Radio chooses BE, Shively (reprinted from Radio Currents, 6/5/06)
• Interdigital combining technology at 4 Times Square (July '05)
• 4 Times Square, NY: 21-station master FM project (April '04)
• Revolutionary IBOC test at Cougar Mountain (August '02)

Typical Data for
Model 6812B FM Antenna (full-wave-spaced)

• True Circular Polarization
• Perfect for Translators
• Digital-Ready
• No Pressurization Needed
• The Choice of Campus Broadcasters
• All Stainless Steel Construction
• Designed for Pipe Mounting
• Economical
• No Factory Personnel Needed to Install
• Radomes and Deicers Available
• Special Spacing, H/V Ratios, Null Fill, Beam Tilt Available

Performance Specifications:

Polarization:

Right circular.

VSWR:

1.1 : 1 ± 100 kHz.

1.2 : 1 ± 200 kHz

Azimuth Pattern Circularity:

Horizontal component ± 1.5 dB.

Input Connection:

Type "N" female.

Mounting:

Must be mounted on a metal pipe, 2" IPS (2-3/8 in; 60 mm) to 3" IPS (3-1/2 in; 89 mm) outside diameter. Pipe not supplied by Shively; requires 5 ft (1.5 m) of clear space on pipe above and below antenna.

Electrical Specifications (full-wave-spaced):

Notes:

Our gain figures are calculated by factoring the directivity to allow for losses in the radiating system. Due to this conservative approach, you are assured of radiating maximum ERP by using Shively's published gain figures.

Gain is provided for one polarization and is equal in circularly polarized antennas for both horizontal and vertical components. Gain will be reduced if null fill, beam tilt, special H/V ratio, or special wavelength spacing is provided.

Size and Weight (full-wave-spaced):

Windload (full-wave-spaced):

Notes:

1. Antenna radiation aperture is the distance from the center of the top bay to the center of the bottom bay. Five feet (1.5 m) of pipe is required above the top of the top bay and below the bottom of the bottom bay. Total tower space recommended allows ten ft (3 m) of clear tower space above and below the pipe to protect from pattern interference by other antennas.
2. Antennas with two bays or an odd numbers of bays are end-fed; antennas with even numbers of bays are center-fed.
3. Windload and weight numbers given are typical. Actual values vary with the specific installation. Contact us with details of your installation if more precise values are needed.
4. Weight, windload, and space tabulations assume 98 MHz and include the bay, interbay feedline, input connection, and standard mounting brackets. At lower frequencies, length will increase by approximately 1 ft (0.3 m) per bay.
5. Antenna windloads are calculated for 112 mph (180 kph), using 50 psf (2400 N/m²) for flats and 33 psf (1600 N/m²) for rounds] per EIA standard RS-222-C and CSA standard S37-94. The surface area is calculated per EIA standard RS-222-F (CaAc).
6. Deicers add approximately 1 lb (4.4 N) per bay in weight and 2 lb (8.9 N) or 0.3 ft² (0.028m²) per bay in windload.
7. Ask for technical assistance at Shively when you are planning to mount antennas on AM towers or install them at altitudes over 3,000 ft (915 m) above mean sea level.

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