Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations Engineering Event Calendar RF Engineering Quizzes USAF radar shop Notable Quotes App Notes Calculators Education Engineering Magazines Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Stencils for Visio RF & EE Shapes for Word Advertising RF Cafe Homepage Sudoku puzzles Thank you for visiting RF Cafe!
Innovative Power Products Couplers

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

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues - primarily having to spend time purging garbage posts from the board. At some point I might start the RF Cafe Forums again if the phpBB software gets better at filtering spam.

Below are the old forum threads, including responses to the original posts.

-- Amateur Radio
-- Anecdotes, Gripes & Humor
-- Antennas
-- CAE, CAD, & Software
-- Circuits & Components
-- Employment & Interviews
-- Miscellany
-- Swap Shop
-- Systems
-- Test & Measurement
-- Webmaster

Guest
 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.)


installed...


RMR assy...
Image

antenna tuning units...
Image

antenna remote control unit
Image

main unit
Image

stealth flyer
Image

Specifications

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 @
70-90º
Bandwidth
(Measured at VSWR 2:1) 20 kHz at 3.0 MHz Carrier
260 kHz at 15.0 MHz Carrier
Gain
(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.
NOTES:
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
Windfreak Technologies ConductRF Phased Matched RF Cables - RF Cafe
Exodus Advanced Communications - RF Cafe Berkeley Nucleonics Academy RF Boot Camp - RF Cafe
About RF Cafe
Kirt Blattenberger - RF Cafe Webmaster
Copyright: 1996 - 2024
Webmaster:
    Kirt Blattenberger,
    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:  AirplanesAndRockets.com

spacer

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free