This document describes the assembly and specifications of the TONNA 1296/23 F9FT Antenna, a 23-element Yagi antenna designed for the 1290-1300 MHz frequency range.
Function Description:
The TONNA 1296/23 F9FT is a high-quality, professional-grade Yagi antenna primarily used for radio frequency (RF) transmission and reception within the 1290-1300 MHz band. Its design, featuring 23 elements, aims to provide high gain and directivity, making it suitable for applications requiring strong, focused signals. The antenna is designed for both horizontal and vertical polarization, offering flexibility in deployment. It can be used as a standalone unit or stacked with multiple identical antennas to further enhance performance, particularly for long-distance communication or specialized RF systems. The antenna's construction emphasizes precision, with elements carefully sized and positioned to optimize its electrical characteristics.
Important Technical Specifications:
Electrical Data (at 1296.0 MHz):
- Effective electrical length: 7.43 wavelengths
- Isotropic gain: 18.0 dB
- Aperture angle at -3 dB:
- E plane: 2 x 10.1 degrees
- H plane: 2 x 10.3 degrees
- First side lobe set:
- E plane: -10.5 dB at 27 degrees
- H plane: -9.3 dB at 27 degrees
- Back to front ratio: -21.1 dB
- Average diffuse radiation:
- E plane: -37 dB
- H plane: -28 dB
- Bandwidth at -1 dB: 1246.4 thru 1324.2 MHz
- Impedance: 50 Ohm
- SWR (1290 thru 1300 MHz): better than 1.25/1
- Maximum acceptable RF power: 300 Watts
Stacking (for two antennas, element center to element center, at 1296.0 MHz):
- Best gain increase (+2.8 to +3.0 dB):
- E plane: 3.19 wavelengths (0.74 m, 29")
- H plane: 2.84 wavelengths (0.66 m, 25" 3/4)
- Best side lobe compromise (-0.16 dB from optimum in E plane):
- E & H plane: 2.84 wavelengths (0.66 m, 25" 3/4)
Mechanical Data:
- Length: 1.75 meters (5' 8" 7/8)
- Weight: 4 kilograms (9 lbs)
Approximate wind load:
- At 25 m/s (90 km/h, 55 mph):
- Horizontal polarization: 2.3 daN
- Vertical polarization: 2.0 daN
- At 45 m/s (160 km/h, 100 mph):
- Horizontal polarization: 7.6 daN
- Vertical polarization: 6.3 daN
- Note: 1 daN (decanewton) = 1.02 kgf = 2.25 pound-force.
Element Lengths (mm / Inches / Color-code / Quantity):
- R: 115 / 4 17/32 / Black / 1
- DE: 102 / 4 1/64 / (no color) / 1
- D1: 99 / 3 57/64 / Brown / 1
- D2: 96 / 3 25/32 / Red / 1
- D3: 95 / 3 47/64 / Orange / 1
- D4: 94 / 3 45/64 / Yellow / 1
- D5: 93 / 3 21/32 / Green / 1
- D6: 92 / 3 5/8 / Blue / 1
- D7: 91 / 3 37/64 / Violet / 1
- D8 to D21: 90 / 3 35/64 / White / 14
Usage Features:
Assembly:
- Element Assembly: Elements are placed in stand-offs and gently tapped through holes (2A and 2B) until properly centered (2C). Care must be taken to avoid bending elements. Elements are color-coded for identification.
- Antenna Assembly: The antenna has a red end indicating the front and a black end for the rear. Directors are counted from rear to front.
- Boom sections are joined using M5 screws (n°6) and clamps (n°9 and n°10).
- Elements are mounted by aligning the bump on the stand-off with the positioning hole on the boom.
- The driven element (DE) comes with a short piece of RG 213/U coax factory-mounted. This coax is run through an 11 mm (7/16") hole, and the driven element is attached with special screws (n°7).
- A supporting bracket is mounted on the boom using M5 screws (n°8) and clamps (n°9 and n°10).
Attaching the Feed Line:
- A high-quality, professional-type coax cable (RG 213/U or better) is required. The RG 213/U has a loss of 29 dB/100m (9.7 dB/100') at 1300 MHz.
- A type N connector (UG 21 B/U) must be mounted at the end of the short coax length extending from the driven element.
- Caution: The connector must be mounted only once the coax has been run through the 11 mm (7/16") mounting hole. The coax length is specifically chosen (an integer number of electrical half-wavelengths) for stacking purposes and is consistent across all manufactured antennas.
Mounting to Mast:
- Caution: No part of the mast or tubing should pass through the element plane to prevent performance reduction.
- It is recommended to mount the antenna on top of the mast or, if not possible, along the mast using an offset arm of at least 1.5 wavelengths long.
- Masts up to 54 mm (1 1/8") diameter are accepted by the attaching set (medalion n°6).
- It is also recommended to position the antenna in the direction of dominant winds when not in use.
Stacking:
- The short length of coax is part of the phasing harness for simplified stacking.
- To ensure antennas are in phase, the plastic injection studs on the driven element stand-offs must all face the same side.
- A special quarter-wave power splitter is available in two versions:
- 4 inputs 50 Ohms, one output 50 Ohms: part n° 29423
- Output available in 75 Ohms upon request.
- A complete stacking frame kit for three-wavelength spacing is available:
- Part n° 20016 for horizontal polarization
- Part n° 20017 for vertical polarization
- The power splitter is designed for stacking four antennas. A combination of five splitters allows stacking of 16 antennas.
- Notes on Stacking:
- Do not use spacing shorter than 3 wavelengths (700 mm, 27").
- A complete set for 4 antennas (part n° 20423), including 1 power splitter (part n° 29423) and 1 stacking frame (part n° 20016), is directly available as part n° 20696.
Maintenance Features:
- Element Integrity: During assembly, utmost care is required to avoid unwanted bending of elements, as this can drastically reduce antenna performance.
- Correct Element Mounting: Each element is marked with a color. The reflector is the longest, and successive directors are either the same length or shorter than the prior one. It is crucial to verify the color order according to the code. Incorrectly mounted elements will severely degrade antenna performance.
- Connector Installation: Proper mounting of the N connector (UG 21 B/U) on the feed line is critical. Instructions for connector mounting should be followed carefully. For the main feed-line, a type N female connector (UG 23B/U) is required. If a larger coax is used, a special connector with the same nose as UG 23/B/U should be used.
- Regular Inspection: While not explicitly detailed, the professional nature of the antenna implies that periodic inspection of all mechanical connections (screws, clamps, mast attachment) and the feed line for wear or damage would be good practice to ensure continued optimal performance and safety, especially given the wind load specifications.
- Environmental Considerations: The recommendation to place the antenna in the direction of dominant winds when not in use suggests a consideration for minimizing stress on the antenna structure, which contributes to its longevity.
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