Could a Yagi antenna be used to transmit non-sinusoidal waves ???
95364
Looking at your various questions, it appears that you are trying to figure out how to transmit square pulses.\n\nAs other posters have noted, a square pulse is the sum of an infinite Fourier series containing the fundamental frequency and every other harmonic.  But since all real systems are band-limited, this is impossible in real-life.\n\nAn adequate representation of a square wave can be created with three to nine harmonics.  Check this link, a little over half way down there is an applet which allows you to view a square wave recreated from limited number of harmonics.\n\nhttp://www.jhu.edu/~signals/phasorlecture2/indexphasorlect2.htm\n\nIf you have a bandlimited system, then you cannot transmit a perfect square pulse.  You can, however, recreate the pulse using digital methods on the receiving end.  Check page 3 of this presentation for the concept:\n\nhttp://www.freedomuniversity.net/ColoradoTechUniv/EE645/LessonNotes/2006/Lesson1/Chapter1web.pdf\n\nSo, possible approach, using your band-limited system, transmit the best representation of the square pulse possible.  At the receiving end, typically you would use a matched filter and integrate the received signal over the sampling frequency.  The output is then compared to a threshold to determine if 0 or 1 is transmitted.  Based on this, you can recreate your square wave.\n\nHope this helps.
796578
Yes, they do....sonar, for example.\n\nThe interface travel between water/air scatters the waves.  You'd probably have to keep the antenna under water.
110616
Every station has a transmitter that radiates radio signals around its area. A lot of the signals reflect off the atmosphere, and this along with the power of the transmitter determines how much area the signal covers.\n\nHow the transmitter sends out a radio signal?\n\nThere's an excellent in-depth discussion on Wikipedia (the link I provide), but I copy here the one important point:\n\n"In principle any conductor (wire) carrying an alternating current will radiate a radio signal. Thus a basic transmitter is just an oscillator connected directly to a wire antenna."\n\nSo you need a conductor with an alternating current going through it. This will send out radio waves. Of course, its more complex if you want the radio signal to contain a voice or song broadcast of course.\n\nRemember that a radio wave is just another type of electromagnetic radiation, along with xrays, and light. The only thing that seperates light and radio is the wavelength (def: every oscillating electromagnetic signal has a property that specifies the distance from one peak of the signal to the next) of the radiation. \n\nOur eyes are basically receivers that can interpret electromagnetic radiation within a certain range. So think of radios as a type of artificial eye that reacts to radio signals, and that a radio station is basically one huge flashlight.\n\nThat's as simple an analogy I can make.
141111
Its like a microwave for metals, only kilohertz instead of gigahertz.  Its done with a coil instead of a magnetron.
84634
probably there are service providers in your area that can offer you WiFi connections across those 10kms with no complexity.\nIf you are trying to do it by yourself, you will need microwave antenas aligned in a careful way at every point which you want to provide conectivity and repeaters, so wireless users can detect those signals
489817
Some where around 300 ghz. Go to www.hamlink/freq.list.html
160050
No they would not.  You need to be within 5 miles of an attenna (with a base station).  Plus the attennas are designed to pick up signals from below them on an angle.\n\nYou also have an ionosphere which would block a great deal of the radio signals.
285555
Satellites use non-linear amplifiers to relay signals back to earth.  Using AM for any type of transmission through the satellite would heavily distort the AM signal and make the signal have very poor quality.\n\nVideo, or more accurately TV signals used to be exclusively distributed via satellite using FM because of its constant envelope characteristic made them largely impervious to the amplitude distortions caused by the non-linear amplification of the satellite.  \n\nHowever, increasingly more video (TV) transmissions are using digital transmission schemes.  Here the baseband TV signal is digitized into some bit format and the bits are used to phase-modulate (PM) the carrier. When PM is digitally modulated it is known as Phase Shift Keying or PSK. This also has a constant envelope characteristic like FM and PM making it suitable for the non-linear amplification of the satellite.\n\nSatellite amplifiers are becoming more and more powerful as the technology improves.  They also are becoming more linearized.  This is allowing digital transmissions to utilize a combination PSK and AM technique known as APSK or sometimes, QAM (Quadrature Amplitude Modulation).  Using these techniques requires the satellite amplifiers to be used at much less than their full power, so they are linear and do not cause large amplitude distortions.  This is done because these newer techniques allow more bits/sec to be transmitted on the satellite channel.  This allows higher quality video (HDTV for example) or just more video signals per satellite channel.
168211
Cheap receivers are possible.  Take AM radio, for example.  It is very wasteful of bandwidth compared to a digital transmission.  However, you can receive AM with a simple envelope detector.  You can receive AM with a "crystal radio"  constructed with only a diode, a coil, a capacitor, and a pair of headphones.
674033
the chassis wont distort the reading. you need to be encompassed in a diamagnetic material for distortion.
65252
High frequency radio waves. Around 1700 Mhz.
516594
Pure sine wave only have one frequency and the form is fully curved with full 360' phase rotation.\nFor modified sine wave, I don't really understand what you mean, maybe it's a sine wave that have been mixed with other frequency or limited in gain/phase.
73968
I have never used them, but I have heard they have uses in certain kinds of electrical engineering.  I think it involves phase shifts of period functions like sine waves.  Also, there are occasional problems where you start in the real numbers and end in the real numbers, but by doing the problem in the complex domain, certain difficult problems become solvable.  I think Cauchy integrals are used for this purpose.
682702
www.tessco.com\n\nWhat type of signal are you trying to enhance??
1022837
I have seen two antennas on many laptops just for that reason. I live in a big city with lots of towers and did not need to do that. It will not hurt any thing and you would only be out a few bucks, so its worth a try.
522363
you can use a fm modulator
767292
They do exist; a good brand to check out would be Oregon Scientific.  Search for Oregon Scientific Wireless Weather Station WMR112A if that's not what you're looking for... let me know.  I know this one doesn't include a NOAA broadcast but I know Wal-Mart carries a cheap handheld to do that for you.  Hope this helps!