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High Performance AM Radio Antenna HPR.0990

The HPR.0990 High Performance Antenna is the heart of the RadioSAFE System.

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The HPR.0990 Antenna’s capacitive “Top Hat” design maximizes efficiency..

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The heavy-duty HPR.0990 Antenna Coil can handle hundreds of watts.

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Downloadable Spec Sheet

Antenna Comparison Chart

This high performance antenna offers a communication professional the ability to establish an AM broadcast signal more efficiently than before possible with an antenna of similar design and price point. Its 50-ohm resonant design requires only a matching transformer at its feed-point, eliminating the need for an antenna tuner (matching network). Designed to operate most efficiently in conjunction with a horizontal groundplane, this antenna is compact and light-weight, making it easy to ship, set up and install. It may be assembled in minutes, if required, for an emergency application.

Waldo County, Maine.
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Portola Valley, CA
Frequency Range and Coverage
Different versions of the antenna's design allow it to function on any frequency in the 470 to 1800 kHz range. Field tests prove that this antenna is capable of handling hundreds of watts, producing a coverage pattern that can exceed 20 miles in radius.
Common users are emergency managers and associated amateur radio operators who want to reach their publics during times when power, other communications and internet services are compromised. Commercial broadcasters can also benefit by using the HPR.0990 High Performance Antenna to keep their AM stations on the air temporarily at low power following calamities. And amateur radio enthusiasts who want a solution for special applications that can be installed in confined spaces will benefit.
Information Radio Station licensees can easily upgrade to the HPR.0990 Antenna. The antenna’s efficiency will allow a 10-watt signal to be produced that is two to four times that of the standard antenna, depending on frequency. A waiver is required from the FCC if an Information Station’s signal intensity would exceed 2.0 mV/m at 1.5 km (0.93 mile) by substitution of this antenna.
When utilized in association with an Information Radio Station for expanded coverage, i.e., RadioSAFE Wide Area Emergency Radio Broadcast Systems, a waiver and/or an emergency Special Temporary Authority (STA) from the FCC is required. Engineering and filings for the required waivers and STAs can be supplied by Information Station Specialists.
Specifications *
  • Power: up to 270 watts carrier (1700 kHz)/100% modulation; up to 180 watts carrier (530 kHz)/100% modulation. See Table 1 below.
  • Frequency Range: Various versions of the antenna's design allow it to function on any frequency in the 470 to 1800 kHz operating range.
  • Impedance: 10-20 ohms (typical) with 50' tip height and 25-50' radius groundplane (typical).
  • Mounting Format: Top of support structure [tower, mast or pole]. Lower 36” of antenna base clamps in insulator mounts which can be attached to a vertical support with a round or flat surface.
  • Type: center-loaded, bottom-fed vertical, whip-type antenna with adjustable 6- element capacitive top hat and adjustable vertical tuning section . Omni directional. Anodized aluminum finish. Guying ring included.
  • Radiation Efficiency Range: 54 mV/m/km at 530 kHz & 171 mV/m/km at 1700 kHz, referenced to 1 KW. See Table 1 below.
  • Audio Bandwidth (2:1 SWR): 530 kHz: +/- 1.5 kHz; 1700 kHz +/- 5.5 kHz. See Table 1 below.
  • Temperature endurance: -40°C to 85°C.
  • Wind endurance: greater than 100 MPH, unguyed. Greater than 140 MPH with the addition of guy lines (nonconductive only).
  • Weight of the complete antenna varies with frequency. 30.5 lbs nominal. Mounts with insulators (2): 5.5 lbs total.
  • Overall assembly: five sections plus capacitive hat. Length varies with frequency and tip extension. Typical: 32'. Includes assembly hardware. Outside diameter of vertical sections taper from 2.5” (lower) to 1.0” (upper). Capacitive hat spoke length varies with frequency.
  • Recommended
    Accessory M.990 Insulators with Stand-Off Mounts
    separation from buildings and structures: 100’ or equal to the height of the structure, whichever is greater.
  • Required: stand-off mounts with insulators. Options: matching transformer, lightning arrestor, weatherproof cabinets, coaxial cable with connectors, guying kit, support poles and masts, roof stands, fully assembled portable groundplanes.
  • RF exposure separation: 1 meter minimum recommended for both occupational and controlled environments.

* These specifications are subject to change without notice.

Table 1

 Frequency Band

Max Carrier Power
100% + Modulation Peaks

Max Carrier Power
125% + Modulation Peaks

2:1 VSWR Bandwidth

Antenna Efficiency

1500 - 1700 kHz

270 Watts

220 Watts

+/- 5.5 KHz

151 - 173

1100 - 1500 kHz

250 Watts

210 Watts

+/- 4.5 KHz

111 - 151

800 - 1100 kHz

230 Watts

200 Watts

+/- 3.5 KHz

81 - 111

650 - 800 kHz

200 Watts

175 Watts

+/- 2.8KHz

66 - 81

530- 650 kHz

180 Watts

155 Watts

+/- 1.5 KHz

54 - 66

Table 2

Table 3
Typical HPR 0990 Vertical & Horizontal Radiation Pattern

(Feedpoint Elevated on20ft Pole - 32 Radials [50ft] at Base of Support)
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PO Box 51, Zeeland, Michigan, USA, 49464-0051, Phone 616.772.2300, Fax 616.772.2966, Email

The USA's go-to source for information radio station equipment, related products and technical services.

Trademarks: 2X Signal Booster, ALERT AM Emergency Advisory Radio System, ANXX AM Radio Antenna, AP.55 Digital Message Player, ENcast Emergency Notification Broadcast System, EventCAST Portable Information Radio Service, FAS.6000 Flashing Beacons & Controller, FASTrack Quick-Erect Sign, FlashCAST Internet Broadcast Service, Flashing ALERT Sign System, Free-Radiate On-Premise Radio Broadcast System, HearMoreInfo Internet Broadcasts, HPR.0990 High Performance Antenna, i A.M. Radio Transmitter, Information Station Specialists, InfoRadio Format, Information Station Classic, Information Station IP, Information Station USB, InfOSpot AM Radio Transmitter Station, InfOspot Drive-Thru AM Radio Station, IP.8 Digital Message Player, IP.76 Digital Message Player, ITS.6000 Highway Advisory Radio Network, MGR.021 Digital Audio Management System, LIGHTNING LED Changeable Message Sign, NX8R Digital Message Player, PowerPlane Preassembled Groundplane, RadioSAFE Wide Area Emergency Broadcast System, RadioSTAT Portable Emergency Advisory Radio Station, RE 2.5 Range Extender Outdoor Antenna and Tuner, RESPONDER 1 Portable Highway Advisory Radio System, RoadRunnR Portable Highway Advisory Radio System, SSD.20 Severe Storm Detector, Signal Measurement Radio Receiver, Stealth Sign, StreamCAST Internet Broadcast Service, SS.3000 Free-Standing AM Radio Antenna System with Tower, SX.200 Wattmeter, Talking House AM Radio Transmitter, TH.5 InfOspot Transmitter, TR.6000 Transmitter Model HQ 5.0, TMS.020 Digital Audio Management System, TR.6000 Transmitter Model 15.73, VoiceStar Portable Highway Advisory Radio Station (with or without Changeable Message Sign), VP.9000 Vertical Profile Antenna Support and Grounding System.

Information Radio Stations is a generic term synonymous with Travelers Information Stations (TIS), Highway Advisory Radio Stations (HAR) / Highway Information Systems & Low Power Radio Stations (LPR). Operation of the stations is governed by FCC Part 90.242 Rules. A FCC license is required. Information Radio Stations may be fixed or portable. Subcomponents may include transmitter, antenna and ground system, digital voice player, wateter, cabinet with conventional or Corbin locks, lightning arrestors for RF, power and telephone lines, coaxial cable. Most stations employ black maximized antennas to discourage ice accumulation and security measures to prevent unauthorized program access. Options include synchronization, battery backup, solar power, remote programming by local, network or telco, multi-station audio distribution via RF or LAN / WAN or wireless network