RWTH Aachen

• With over 31,000 students---most of them enrolled in engineering courses---and 260 institutes in nine faculties, the RWTH Aachen is Germany's largest technical university, offering more than 100 courses of study. Located in one of Germany's oldest cities and nestled close to the borders to Belgium and the Netherlands, the RWTH maintains close co-operations with Belgian and Dutch universities. According to the 2009 THEQS rankings, the RWTH is the 57th best engineering university in the world.

  Rheinisch-Westfaelische Technische Hochschule Aachen
  Templergraben 55
  52056 Aachen
  Germany
  011-49-241-80-1
  rwth-aachen.de

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Technical University of Berlin

• Located in the heart of the German capital the TU Berlin is Germany's second largest technical university with over 27,000 students. Ranked 62nd in the 2009 THEQS list, the TU Berlin offers 90 courses of study, employs 322 professors and 14 junior professors, and maintains co-operations with over 100 international universities and institutes in 36 countries.

  Technische Universitaet Berlin
  Strasse des 17. Juni 135
  10623 Berlin
  Germany
  011-49-30-314-0
  tu-berlin.de

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Braunschweig University of Technology

• Founded in 1745, the Braunschweig University of Technology (TU Braunschweig) is Germany's oldest technical university. On the smaller side with 13,000 enrolled students the TU Braunschweig excels in research related to hybrid engines and micro air vehicles, and is the government-appointed German institute for establishing fire-resistance ratings. The TU Braunschweig maintains international academic co-operations with over 200 schools all over Europe and offers dual degree programs. The THEQS rankings list the TU Braunschweig in 285th position.

  Technische Universitaet Carolo-Wilhelmina zu Braunschweig
  Pockelsstrasse 14
  38106 Braunschweig
  Germany
  tu-braunschweig.de

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Darmstadt University of Technology

• Spread over 138 buildings, the Darmstadt University of Technology (TUD) offers 100 degree courses, 272 professors and an academic staff of 2,150. This group teaches 21,000 students just 20 miles outside of Frankfurt. Numerous reputable engineers are closely connected to the TUD: Rolf Isermann---a renowned expert in digital automation technology and mechatronics, whom the Massachusetts Institute of Technology ranked as one of the world's "top ten" researchers in the field of future technologies--has been teaching at the TUD since 1977. The 2009 THEQS ranking lists the TUD in 119th position.

  Technische Universitaet Darmstadt
  Karolinenplatz 5
  64289 Darmstadt
  Germany
  tu-darmstadt.de

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Technical University of Dresden

• The Technical University of Dresden (TUD) is known as a research-focused institution, a status not quite reflected in the THEQS list that ranks the TUD in 195th position. With 419 professors and nearly 35,000 students, the TUD is among the largest technical universities in Germany. The TUD is the only university from the former German Democratic Republic in the TU9 network, and it features a total of 14 faculties that focus on practice-oriented courses.

  Technische Universitaet Dresden
  Helmholtzstrasse 10
  01069 Dresden
  Germany
  tu-dresden.de

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Leibniz University of Hannover

• Four out of nine faculties at the Leibniz University of Hannover (LUH) are dedicated to engineering: the Faculty of Architecture and Landscape Sciences, the Faculty of Civil Engineering and Geodetic Sciences, the Faculty of Electrical Engineering and Computer Science, and the Faculty of Mechanical Engineering. The Faculties of Natural Sciences and of Mathematics and Physics round the technical focus of the LUH that also includes a law school, a management school and the Faculties of Humanities. Founded in the 19th century with just 64 students, the LUH is now the academic home to approximately 21,000 students and offers about 75 courses of study.

  Gottfried Wilhelm Leibniz Universitaet Hannover
  Welfengarten 1
  30167 Hannover
  Germany
  uni-hannover.de

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Karlsruhe Institute of Technology

• Ranked as the 71st best engineering university in the world, the Karlsruhe Institute of Technology (KIT) is the technology division of the University of Karlsruhe. It was founded it 1825 and is the oldest technical university in Germany. As of 2010, more than 18,000 students are enrolled in KIT courses.

  Karlsruher Institut fuer Technologie
  Kaiserstrasse 12
  76131 Karlsruhe
  Germany
  kit.edu

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Technical University of Munich

• Comprising of 13 faculties, the Technical University of Munich (TUM) has established itself as Germany's foremost technical and engineering institution. Six Nobel Prizes grace the Institution's impressive list of awards and achievements. The quality of study is reflected in the 2009 THEQS list that ranked the TUM 45th, making it the only German school in the top 50. The TUM offers about 130 courses of study, some of which are completely or partly held in English and about one fifth of the students hail from abroad.

  Technische Universitaet Muenchen
  Arcisstrasse 21
  80333 Muenchen
  Germany
  tum.de

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University of Stuttgart

• Rounding up the TU9 is the University of Stuttgart (US), that snatched up the 89th position in the 2009 THEQS rankings. Located in the center of a region known for technological excellence and progressive engineering, the US has established itself as an achievement oriented academic institution since its founding days in 1829. About 19,000 students flock the US campuses. Six out of the university's ten faculties are dedicated to engineering disciplines. Famed German astronaut Ulf Merbold and car pioneer Gottlieb Daimler are among the alumni.

  Universitaet Stuttgart
  Pfaffenwaldring 60
  70569 Stuttgart
  Germany
  uni-stuttgart.de

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آموزش تعمیر لامپ کم مصرف

توی خونه نشسته بودم که دیدم یک دفعه لامپ بالای سرم خاموش شد نگاه کردم دیدم همون لامپ کم مصرف ی هست که یک هفته پیش خریدم حالا سوخته و... کلی ناراحت شدم و گفتم نمیشه که هر روز من بخرم اینها هم هر روز بسوزن پس استین هامو بالا زدم و رفتم یه چهار پایه اوردم و از داخل جا لامپی بازش کردم که برم روی سر فروشنده و  ...

که یک دفعه به خودم گفتم تو که نشستی کلی الکترونیک خوندی حالا چطور میشه اینو باز کنی ببینی داخلش چی هست اقا بازش کردم دیدم اوه ه ه ه  به نظر میاد همه چیزش سالمه پس دست به کار شدم که

ادامه نوشته

OOK/ASK data in the 300MHz to 450MHz frequency range

*At 50% duty cycle (315MHz, 2.7V supply, +10dBm output power)

Diagram

Typical Application Circuit

The MAX1472 is a crystal-referenced phase-locked loop (PLL) VHF/UHF transmitter designed to transmit OOK/ASK data in the 300MHz to 450MHz frequency range. The MAX1472 supports data rates up to 100kbps, and adjustable output power to more than +10dBm into a 50Ω load. The crystal-based architecture of the MAX1472 eliminates many of the common problems with SAW transmitters by providing greater modulation depth, faster frequency settling, higher tolerance of the transmit frequency, and reduced temperature dependence. Combined, these improvements enable better overall receiver performance when using a superheterodyne receiver such as the MAX1470 or MAX1473.

ادامه نوشته

Universal LNB

As you may know, from reading our LNB page, a "Universal" LNB has two internal oscillators - a 10.6 GHz oscillator for "high frequency band" and a 9.75 GHz oscillator for "low frequency band". It selects "high band" when it receives a 22 kHz tone from the coaxial cable. In addition, it responds to the input voltage for polarisation selection (13 volts selects vertical and 17 volts selects horizontal polarisation. The changeover point is around 14.5 to 15.5 volts so the supply voltage must be above or below that range for reliable switching of polarisation). The 22 kHz tone is a 0.5 volt "ripple" which is superimposed on the 13v or 17v supply voltage.

That's the technical stuff. You don't need to understand what it means, provided that you understand that:

13v = vertically polarised signals are received
17v = horizontally polarised signals are received
22 kHz = high band is received
no 22 kHz = low band is received

http://www.satcure.co.uk/tech/satmeter.htm

Antenna Patterns

Gain for an antenna is expressed in decibels relative to an isotropic radiator (point source that radiates equally in every direction). Physical attributes of an antenna, in conjunction with the operating frequency, results in constructive and destructive interference patterns being set up a points distant from the antenna. Where the fields add constructively a positive gain is experienced, and where fields add destructively a negative gain is experienced (relative to isotropic).

Narrowband BW (%)
   = (f_U - f_L) / f_C

Broadband BW
   = f_U / f_L

%	Ratio
5	1.05:1
10	1.11:1
20	1.22:1
30	1.35:1
40	1.50:1
50	1.67:1
60	1.85:1

%	Ratio
67	2:1
100	3:1
120	4:1
133	5:1
150	7:1
160	9:1
163	10:1

Note:  Keep dimensional units similar; i.e., meters, inches.

http://www.rfcafe.com/references/electrical/antenna-patterns.htm

ادامه نوشته

Square Loop

	Elevation Pattern	Gain (typ): 1 to 3 dB Bandwidth: 10% (1.1:1) Frequency Limit: Lower - 50 MHz                          Upper - 1 GHz Polarization: Linear (horizontal as shown) Half-Power Beamwidth (typ):                                   100º x 360º
	Azimuth Pattern

Horn

Horn
	3 dB beamwidth 56 * λ / h Elevation Pattern	Gain (typ): 5 to 20 dB Bandwidth: 120% (4:1) - ridged                  67% (2:1) - non-ridged Frequency Limit: Lower - 50 MHz                          Upper - 40 GHz Polarization: Linear (vertical as shown) Half-Power Beamwidth (typ):                                        40º x 40º
	3 dB beamwidth 70 * λ / w Azimuth Pattern

Circular Loop

	Elevation Pattern	Gain (typ): -2 to 2 dB Bandwidth: 10% (1.1:1) Frequency Limit: Lower - 50 MHz                          Upper - 1 GHz Polarization: Linear (horizontal as shown) Half-Power Beamwidth (typ):                                      80º x 360º
	Azimuth Pattern

Yagi Array

Yagi Array
	Elevation Pattern	Gain (typ): 5 to 15 dB Bandwidth: 5% (1.05:1) Frequency Limit: Lower - 50 MHz                            Upper - 2 GHz Polarization: Linear (horizontal as shown) Half-Power Beamwidth (typ):                                       50º x 50º
	Azimuth Pattern

Vertical Whip Antenna, 1/4 Wave

Configuration	Elevation Pattern	Gain (typ): 2 to 6 dB Bandwidth: 10% (1.1:1) Frequency Limit: Lower - none                            Upper - none Polarization: Linear (vertical as shown) Half-Power Beamwidth (typ):                                     45º x 360º Notes: Polarization changes to horizontal if antenna is rotated to horizontal.
	Azimuth Pattern

Dipole Antenna, 1/2 Wave

	Elevation Pattern	Gain (typ): 2 dB Bandwidth: 10% (1.1:1) Frequency Limit: Lower - none                            Upper - 8 GHz                               (due to size) Polarization: Linear (vertical as shown) Half-Power Beamwidth (typ): 80º x 360º Notes: Pattern and lobing change significantly with L/f. Used as gain reference for f < 2 GHz.
	Azimuth Pattern

Parabolic Antenna

Gain (typ): 10 to 60 dB

Bandwidth: 33% (1.4:1)

Frequency Limit: Lower - 400 MHz
   (due to size)    Upper - 13+ GHz

Polarization: Polarization of feed

Half-Power Beamwidth: 1 to 10º

G=20 log (D/λ) + 10 log (a) + 9.938 dB

D= diameter   a = illumination factor                  (typ = 0.6)   λ = wavelength