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New product ST940B covert half loop autotune HF antenna - RF Cafe Forums

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 Post subject: New product ST940B covert half loop autotune HF antenna
Posted: Tue Feb 07, 2006 6:30 am 
Tentative batch of 30nos of ST940B antenna system is released. System is developed by request of UN. Please address all comments to george@stealth.ae (Stealth Telecom Ltd.)


RMR assy...

antenna tuning units...

antenna remote control unit

main unit

stealth flyer


General Specifications ST-940B
Frequency Range 2.7 ? 15.0 MHz, ±2%
Power Rating 125 W PEP
Input Impedance 50 ohms
VSWR Not greater than 1.3:1
Pattern Radiation Omni directional, HRP offsets are less than 1 dB at two opposite minimas,
Vertical Elevation ? NVIS lobe @
(Measured at VSWR 2:1) 20 kHz at 3.0 MHz Carrier
260 kHz at 15.0 MHz Carrier
(compared to ideal 1/4? GP*) -0.32dB @ 15 MHz; -1.27dB @ 7 MHz;
-2.17dB @ 3.5 MHz;
Power Supply Voltage 12-14VDC/ 4 A (peak current)
Tuning Method Continuously Variable Tuning
Tuning Time 3 seconds average, 8 seconds max.
Tuning Accuracy ± 1.8º step or :
Approx. ±200 Hz at 3.0 MHz
Approx. ±15 kHz at 15 MHz
Tune Signal 4-30 W PEP CW followed by logic
consequence via 4 I/O programmable interface
Tuned Point Instability
Wind/Vibration Not detected at speeds up to 150 km/h
asphalt and up to 90 km/h off-road

Tuned Point Thermal Instability
(within 3 min under 100 W PEP CW) Less than 500Hz negative
drift @ frequencies below 4 MHz
Less than 10Hz negative drift @
frequencies above 4 MHz
Feeding method Shunt fed, ?-match in series with
preset reactance
System Serial Bus RS-485, differential
Programming Port RS-232
Dimensions H x W x L,
(without mounting brackets) Folded Up: 740** x 1254 x 1852 mm
Folded Down: 175 x 1254 x 1852 mm
Weight (without mounting brackets) 36 kg
Sealing Withstands rain testing per MIL STD 810 C/D/E
Shock/Vibration Protection provided via Impact
resistant vibroframe
Dust and Humidity Protection provided via environmental
resistant housing to MIL STD 810
C/D/E and connections to MIL C26482.
* If compared with mobile loaded whips approx. 0.6 dB to be added at all three frequencies.
Data is specified for +25Cº unless otherwise stated. All specifications listed are typical.
Specifications are subject to change without notice and are issued for guidance purpose only.

Posted  11/12/2012
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