ISS antenna is an possibility in an AM pinch
It meets the need for an inexpensive, compact AM and TIS antenna
Radio World’s recent article, “Quick, We Need a Temporary AM Antenna,” demonstrated the ingenuity of WMJC engineers in trying to get a station back up and running quickly.
Improvised antennas are a way of getting back into the air and can serve as an acceptable emergency or auxiliary antenna in a pinch. However, they may not be the best or easiest way to get an AM station back up and running.
The HPR.0990 is designed for a transmission power of up to 250 watts.
AM stations faced with the dilemma of a damaged antenna or that have failed due to maintenance or replacement have a commercially available option that is inexpensive, quick to deploy, and allows them to stay airborne with adequate coverage.
The information station specialist HPR.0990 is a vertical monopole antenna loaded with a resonance center and a cylinder with an integrated 50 ohm transmission line adapter and an optional floor radial system with quick deployment.
In a typical installation, a simple wooden or metal support pole or short tower must be installed to mount the self-supporting antenna to its base using a quick deploy ground floor system or a connection to the station’s existing ground floor system.
The antenna is mounted on the side of the carrier with the supplied saddle clamps in order to attach it to the support rod. Due to its resonant design and integrated impedance matching, the HPR.0990 can be connected directly to the 50 ohm coaxial output of the transmitter without the need for an additional impedance matching network.
The base of the antenna is ideally mounted about 15 to 20 feet above the ground, which places the top of the antenna about 45 to 50 feet high. This installation configuration using the ground radial system with rapid deployment shows a measured efficiency of 100 mV / m per kilowatt at 1000 kHz rising to 175 mV / m at the top of the AM band. The efficiency of HPR.0990 gradually decreases as the operating frequency moves to the lower edge of the band AM band due to the longer wavelengths. Despite its small size, the HPR.0990 can still generate an efficiency of 55 mV / m per kilowatt at 540 kHz.
Adjustment and installation is quick and easy once the support mast is up and secured. The HPR-0990 is designed for transmission powers of up to 250 W.
There are currently four HPR.0990 installations in temporary commercial use serving stations in Connecticut, Pennsylvania, Virginia and Iowa. In addition to commercial applications, the HPR.0990 is well suited for use under Part 90.242 as an antenna for the Travelers Information Station with higher efficiency.
My familiarity with the HPR.0990 is based on my role as an assistant to Information Station Specialists in the design, development and testing of this antenna as a contract engineer. The antenna grew out of the need for a more efficient, lower cost, compact, medium power AM and TIS antenna.
Due to the success of the on-site deployment, the HPR.0990 has achieved these goals.
The author worked for Collins Radio and spent most of his career at General Motors Engineering and Delphi / Delco Electronics as an advanced development engineer and technical manager for the design of car radios and infotainment products. He founded the engineering office PD Technologies.
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