ROTOTILLER® H Series Horizontally Polarized FM Antenna

The ROTOTILLER® H Series horizontally polarized FM (88 – 108 MHz) antenna combines the exceptional engineering features of an internally fed, fully pressurized system with superior fabrication characterized by totally welded feed connections, rugged brass material and TIG welding.


  • Product Line:
  • Product Series:
    H Series
  • Frequency Range:
    88 - 108 MHz
  • Multiplexed Versions Available:
  • Broadband Applications:
  • Polarization:
  • Azimuth
    ± 2 dB in free space
  • VSWR at Input:
    1.07:1 or less (with field matching)
  • 1.25:1 or less (with top pole or LAMBDA™ Mounting System)
  • 1.50:1 or less (top mounted without field matching)
  • Maximum Power Rating:
    120 kW

The H series, horizontally polarized antennas will afford broadcasters all the advantages of ERI’s standard internal feed and fully pressured design, plus higher antenna gains and increased omnidirectional pattern characteristics.

Horizontal polarization only allows station owners to choose between circular polarization or increased antenna gain to achieve optimum market penetration. Maximum allowable ERP is maintained while reducing the required transmitter power and minimizing cost.

The H Series antenna can also be combined with the P-300 series (vertical only) antenna to achieve custom horizontal to vertical component ratios. This technique can be useful in reducing the problems associated with multi-path in mountainous terrain. The antenna’s rugged construction and resistance to the effects of radial ice make this combination unbeatable.

Both antennas are constructed of large diameter copper tubing, brass fittings and TIG welding. The antennas operate in a totally pressurized environment with all welded feed point connections. These features contribute to the superior power handling capabilities, excellent bandwidth and durability of the system. The antenna pattern is ± 2 dB when mounted on a Lambda system or on a small diameter antenna pole. Side mounting the antenna on a typical tower structure will affect the azimuth pattern. ERI offers pattern measurements and optimization to improve the circularity of the antenna system.


  • Low VSWR, Superior VSWR Band Width, Minimal weather related VWSR problems
  • Internal feed, Fully pressurized, Welded feed connections, Series fed radiation elements
  • High input power capacity
  • Modular construction facilitates easy installation and repair, Custom modifications are available
  • Rugged brass construction - TIG welding, Stainless steel support brackets and hardware, Corrosion resistant construction

Type Number Definition

SHP-H - a b c d - e
  • a
    Number of Bays
  • b
    Interbay Line Size: A = 3 1/8 inch | B = 4 1/8 inch | C = 6 1/8 inch
  • c
    Input Feed Configuration: E = End Fed | C = Center fed for even number of bays, off center fed for odd number of bays
  • d
    RF Input Size: Blank = 3 1/8 inch | 6 = 6 1/8 inch
  • e
    Design Note 1: Blank = Omnidirectional | DA = Directional Azimuth Pattern
  • Example
  • Description
    ERI Model SHP-H ROTOTILLER FM Antenna, two bay, 3 1/8 inch interbay line, center fed.


  • Anti-Rotation Brackets (per bay)
  • Beam tilt (center fed antennas only)
  • First null fill (center fed antennas only)
  • Second null fill (center fed antennas only)
  • Deicers (600w/220v) one required per bay.
  • Export packing

Mounting Information

Utilize the ERI Advantage

Combine an ERI antenna with an ERI Mounting Structure, Pattern Measurement and Installation. Assure yourself of the best antenna/tower interaction. ERI’s Pattern Measurement service will provide the crucial answers concerning the relationship between the antenna mounting orientation and antenna pattern.

ERI Mounting Sections are designed to achieve optimum antenna performance while reducing weight and wind loads. Only ERI can offer you an antenna/tower/installation package that will achieve your highest expectations in a demanding FM market. Contact Electronics Research for complete electrical and mechanical specifications.

Related Publications

ROTOTILLER® H Series Horizontally Polarized FM Antenna Product Brochure

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