Efficient HF Submarine Antennas Presenters Frank Plonski of

Efficient HF Submarine Antennas Presenters Frank Plonski of HI-Q-Antennas Charles M. Gyenes of HI-Q-Antennas JULY 10, 2008

Overview • Background - Abstract/Problem/Solution • Antenna - Design parameters/Description • Performance - Data/Measured/Calculated/results

ABSTRACT For submarine applications, it is desirable to have broadband, efficient, extremely short HF antennas that can cover the whole band without the use of a complex internal/external tuning circuitry. A short monopole antenna is currently used except that it has the following disadvantages: it is not efficient and uses complex external tuning circuitry. An electrically efficient small packaged submarine antenna that operates at the HF band was developed using existing subminiature aperture technology. In this paper, we detail the HF submarine antenna technology and performance results focusing on existing efficient submarine HF communications antennas.

PROBLEM • Hard to achieve efficient HF performance in small restricted Radome cylindrical size • Current HF submarine antennas are very inefficient radiators • Complex antenna couplers decreases reliability and increases maintenance • Heat exchangers removing non-radiated RF generated heat are undesirable

SOLUTION (installed on HMS Gotland) • HI-Q-4/2 -30 installed on HMS Gotland Submarine HF Communications Antenna • HI-Q antenna has higher radiation efficiency then any other short HF submarine antenna designed to date • HI-Q antenna has only one moving part • No external complex antenna couplers

Design Parameters PARAMETER HMS GOTLAND REQUIREMENT HI-Q ANTENNA DELIVERED Volume 92 X 4. 0 inches Frequency 2 -30 MHz 1. 5: 1 Nominal Power 500 watts 1500 watts Radiation Patterns Omni-directional in Azimuth Gain @ 2. 0 MHz -12 d. Bi Minimum rising to + 4. 5 d. Bi @ 30 MHz Impedance 50 ohm Polarization Vertical VSWR

Antenna Description ( Specific to the HMS GOTLAND) • HI-Q-4/2 -30 is a broadband, ultra small HF aperture, 2 -30 MHz tunable antenna • Inductively tuned from 2 -20 MHz Re. Entrant Coaxial Capacity Hat antenna, a very broadband monopole from 20 - 30 MHz. • Antenna consists of a lower mast, a tunable loading coil, a Re-Entrant Capacity Hat, and an antenna controller. • Remotely tunable (5 sec) with +24 vdc motor or a stepper motor

DIMENSIONS AND MASS ( Specific to the HMS GOTLAND) • Total height: 92 inches max (includes connectors) • Diameter: 4 inches max (includes screw-bolt heads) • Weight: 20 lbs (approx)

HI-Q-Family of Submarine Antennas HI-Q-6 -2/30 HI-Q-5 -2/30 HI-Q-4 -2/30 HMS GOTLAND

HI-Q-4/2 -30 Measured VSWR ( Specific to the HMS GOTLAND)

Computed Radiation Pattern and Gain

HMS Gotland HF Antenna Installation

Antenna Performance • 2 - way worldwide communications achieved using HI-Q-6/2 -30 MHz Virginia Class prototype • Demonstrated high Radiation Efficiency by 2 - way communications (5 x 9) • EXAMPLES: 1. 850 MHz USA and Canada (20062007 winter), 3. 795 MHz From near San Diego California to Hawaii, China, Japan, Australia, New Zealand, 3. 798 MHz to South Africa, 7. 250 MHz daily contacts within USA, Canada, Europe, 14 -18. 0 - 21. 0 MHz world wide with 100 watt RF SSB

CONCLUSIONS • In this paper we have reviewed some of our calculated and experimental results on design of electrically short HF antennas. • The HI-Q antenna has higher radiation efficiency then any other short HF submarine antenna designed to date. • High Reliability – one moving part • Very COST Effective

Acknowledgments NAVSEA-PHL contributing team members on the Hi-Q antenna integration into the HMS GOTLAND Submarine sub-safe mast Mr. James Stiles of NSWC-CD Philadelphia Mr. John Ledder of NSWC-CD Philadelphia Mr. John Dolan of NSWC-CD Philadelphia Mr. Jason Batcho of NSWC-CD Philadelphia Mr. Frank Plonski of NSWC-CD Philadelphia Mr. Allan Heong of GDIT- Philadelphia