Active Antenna MF-HF Shortwave Reception

active antenna

Naval electronics

VPA 30 Active Marine Antenna
Receiving MF-HF for distribution throughout the Ship

For many years, Naval Electronics has been a recognized design and manufacturing company for shipboard antennas and CATV/MATV-systems. The experience gained during this period, has gone into the new VPA30 active receiving antenna. Thorough design of mechanical and electrical parts will give years of troublefree, high performance, meeting the very special demands put on shipboard antennas. The VPA-30 is a very compact active antenna optimized for AM reception from 100 kHz to 30 Mhz and the FM broadcast band of 88-108 MHz. The antenna is omnidirectional and senses vertical polarization.

Features:

-Antenna factor Ka=0.16 with overall length 0.85 m.
-High signal handling capability, desensitization 1 dB at 10 V/m input.
-Extremely low intermodulation.
-External noise limited (50% probability according to CISPR 322).
-Die-cast hydronalium body, which is salt water resistant.
-Lightning arrester built in.
-Recognized equipment by Det Norske Veritas, approval no A-4531. Cold test according to USSR Register of shipping. Salt mist test according to DEF-STAN 810D.

TECHNICAL SPECIFICATIONS

AM Frequency range (Mhz) 0.1-30
Output impedance*(ohm)75
Returnloss (dB) >17 IP2 in (V/m) 1250 IP2 out (dBm) +60
IP3 in (V/m) 150 IP3 out (dBm) +38
Antenna factor Ka 0.16 Antenna noise
External noise limited (50% probability according to CISPR 322)
FM Frequency range (MHz) 68-110
Output impedance (ohm)
75 Return loss (dB) 8 Antenna gain (dBi) typ 3
AM-FM Overall frequency range (Mhz) 0.1-110
Polarization Vertical

MECHANICAL

Coaxial connector* 75 ohm female BNC
Rod length (mm) 850
Rod diam. (mm) 10
Base height (mm) 200
Base max diam. (mm) 84
Mounting pipe diam. (mm) 45-50 Weight (kg) 1.65

POWER & ENVIRONMENT

Supply voltage DC (V) 15+17%
Supply current (mA) 115+10
Temperature range (C) -40 - +70

Active Antennas -vs- Longwire Antennas

Compact Size - The VPA-30 antenna is only 850 mm tall. The internal amplifiers make up for the relatively small size of the receiving elements, delivering signals equal to much larger passive antennas. Output Impedance is a constant 50-75 ohms across the entire frequency range of the antenna, making an antenna tuner totally unneccessary. Omnidirectional reception pattern makes the VPA-30 antenna perform equally on signals coming from all directions, while longwire antennas exhibit some directionality.

On shortwave, short vertical antennas like the VPA-30 demonstrate quieter reception with much less atmospheric noise than wire antennas, especially important on lower shortwave frequencies.
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On the FM Radio band a remote passive antenna is subject to severe feedline losses, resulting in weaker signals at the receiver's antenna input. The internal low-noise amplifier of the VPA-30 increases signal strength before any cable losses are encountered, delivering much stronger signal levels to the receiver.
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Naval Tampa is prepared to develop compact active receiving antennas on special order for Govt, Military and Aeronautical use.
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e-mail ..sales@naval.com