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818-4
Sidemount FM Dipole
818 Series

These vertically polarized antennas for FM broadcasting applications are intended for use where low wind loadings are required. They are designed to be sidemounted to a tower leg or pole and optional mounting brackets are available for this purpose.
The 818 series are fabricated from stainless steel and will handle up to 5kW per bay.
Multiple element arrays are supplied as a complete package including power dividers and distribution cables. An optional input tuner ensures optimum VSWR performance after installation as it enables the effects of tower steelwork to be eliminated. Beam tilt and null fill can be provided on request.
The 818 series can be arrayed in multiple bays as required.

FEATURES / BENEFITS

  • Rugged construction for maximum corrosion protection
  • Broadband operation
  • Multichannel use if required
  • Optional pressurization
  • Low windload to minimize tower or mast costs
  • Vertical polarization
  • Temperature range -40 to +60 degrees C available.


818 Series showing 818-4 Antenna

Technical features

Structure

Product LineAntenna TV
Product TypeBand II (VHF) FM 818-4 Sidemount Antennas

Electrical Specifications

Frequency Range MHz87.5 - 108
PolarizationVertical
Nominal Gain (Mid-band) dBd7.94
Azimuth Radiation PatternOmni directional + 3 dB Note 1
Return Loss dBTypically 20 over 6MHZ bandwidth . Tunable within band
Power Rating kW16
Input/Power Rating CommentPower ratings are for single input 7-16 input models.
7/8" input limited to 5 kW.
Dual input cavity versions can provide higher power ratings. Contact RFS for details.
Connector types and impedance may be varied to suit customer requirements, contact RFS for details.
Impedance (unbalanced) Ω50

Mechanical Specifications

Input Connector7/8" EIA Flange
1-5/8" EIA Flange
3-1/8" EIA Flange
Dimensions (Height or Length) cm (in)151(59-1/2) Single antenna
Dimensions (Width) cm (in)6 (2-3/8) Single antenna
Dimensions (Depth) cm (in)84 (33-1/8) Single antenna
Mounting (Standard) mm (in)Brackets for clamp diameter 43 - 76mm (1-3/4 - 3)
Effective Area Front (full antenna) No Ice m² (ft²)0.80 (8.6) Note 3
Effective Area Front (full antenna) with 12.5mm(0.5") Radial Ice m² (ft²)0.80 (8.6) Note 3
Effective Area Power Divider m² (ft²)0.13 (1.4) Note 3
Effective Area CommentNote 3 Connecting cables are not included in calculations - 0.03sq m. per metre length should be allowed.
Wind Load @ 50 m/sec Front kN (lb)1.1 (247)
Wind Load Comment Power divider included and considered adjacent to antennas.
Calculated in accordance with AS1170-1989, Part 2:" SAA Loading Code - Wind Forces".
Pressurization Operational kPa (psi)10 - 25 (1.5 - 3.6) 7/8" EIA Version
Pressurization Test kPa (psi)100 (15) 7/8" EIA Version
Weight kg (lb)82 (181)

Packaging Information

Shipping Weight, Kg (lb)kg (lb)82 ()


Azimuth Radiation Pattern (Typical)


Vertical Radiation Pattern

External Document Links

Notes

Note 1 When antenna is mounted on a mast/tower with a face width of less than 150mm (5.9"").
Note 2 Input power is limited to 5kW if a 7/8"" connector is used, 4.0kW for 7-16 DIN connector.
Note 3 Connecting cables are not included in calculations - 0.03sq m. per metre length should be allowed.
Note 4 Power divider included and considered adjacent to antennas.
Note 5 Calculated in accordance with AS1170-1981, Part 2 ""SAA Loading Code - Wind Forces"".