Is there such a thing as a broadband Parabolic antenna ???
95368
No problem!  A parabola is a parabola.  The distance from the parabola to the focus is the same no matter the wavelength.  Your 3 dB beam width and antenna gain will, however, vary with wavelength.  The antenna gain (EIRP) is given as\n\nGmax = nu(pi D f/c)^2\n\nwhere nu is your antenna efficiency (0.5-0.8 is typical), D is the diameter of the antenna, f is your frequency, and c is the speed of light, 3*10^8 m/s\n\nYour 3 dB width (an approximation) is given by:\n\nTheta = 70(lambda/D) = 70(c/fD)\n\nlambda = wavelength, D = diameter of your dish, c = speed of light, f=frequency\n\nIn order to make this work, you will need multiple feeds, typically appropriate length dipoles tuned for each band, at the focus of the parabola.\n\nMake sense?
378826
DLeibowitz nailed it for you.  I could add that the best reception can often be obtained by holding the receiver antenna similar to the transmitter antenna, especially for weak signals such as walkie-talkies.  Both should be held vertical (or horizontal) but parallel at right angles to the line-of-sight.  When riding in a vehicle, there may be dead spots and even how you point the vehicle when parked may help bring in a weak signal, especially with long whip antennas.  The signals will pass through ordinary glass (real old timers used to open their windows!) and wood but can be interferred with by intervening metal wires and objects that act like antennas.  The earliest "radio signals" were sparks (and radio operators on ships at sea were called "sparky").  Your radio may even pick up the "sparks" of an arcing spark plug wire in a car passing by (or the "sparks" of lightning storms even far away).  All home radios used to have antenna connections but AM receivers now often use the house wiring.  FM antennas may be circular rather than straight wires (or even small wire coils within the set).  FM broadcasts are more line-of-sight than AM broadcasts that can bounce off the ionosphere as well as transmit line-of-sight.  Short wave receivers could even receive foreign broadcasts that bounced all the way around the earth (but often faded in and out when the path was interupted).  Exceptionally short radio waves such as used by cell phones need very short antennas and the transmitted waves are very penetrating prompting current concerns that long time use may possibly contribute to brain tumors.  Remember that X-rays that are far shorter (higher frequency) than visible light waves are far more penetrating too.
418780
I don't think there are many, if any.\n\nYou might like to try a PBX adapter like http://techshop.earthlink.net/p10601:S0063012
893250
Lol...the guy above me was pretty helpful! Not! OK, try checking out Sirius for some local stations in your area - they have a LOT of Internet-based channels in a variety of genres. Good luck.
693045
if you look you can buy cheap world band radios that will pick up signals for around 20 dollars at Walgreen's strong signals only or radio shack. the first link is for on line listing the other links are for shortwave links  some ham clubs will also offer a listing over Internet \n\ngreat hobby have fun
741290
A helical antenna is a conductor wound in a helix -- like a slinky. I'm not sure what you mean by types. Depending on the wavelength of the conductor it can be broadside or end fire; perhaps that's what you mean. Try here:\n\nhttp://en.wikipedia.org/wiki/Helical_antenna
588321
No, it is not.\n\nAn antennae is a reacive circuit normally tuned to resonance at the transmitting frequency. In such case it will produce a damped series of oscillations when energised by a pulse. Theoretically it would not, if the energising signal was a perfect sine wave and cut off at the zero crossing point exactly. However no wave generated by a 1Ghz oscillator will be a perfect sine wave and therefore the tendency of the antenna circuit to oscillate will produce at least a blurring or extension of the waveform beyond the single cycle.\nIf the antenna was not resonant then it would produce reflective waveforms and these will oscillate until their energy is dissipated. \nConsidering the fact that it is not possible to create any antenna system (including the transmission line) without some SWR, then the answer to your question is no.
869072
http://www.ee.surrey.ac.uk/Personal/D.Jefferies/yagiuda.html\n\nhttp://en.wikipedia.org/wiki/Yagi_antenna\n\nhttp://whatis.techtarget.com/definition/0,,sid9_gci214378,00.html\n\nhttp://www.ee.washington.edu/circuit_archive/circuits/yagi.txt\n\nhttp://ic.arc.nasa.gov/people/jlohn/Papers/ices2001.pdf
1058973
Yup\nI used to have one, I used a Buffalo Wireless Air station connected to my phone line, with two wireless connections on the PC's.  They can then connect to each other via the wireless element and to the internet via hard wire.\n\nWorked well and I also used it when I went broadband the first time, but had to set it up so one computer had the broadband modem via a USB and the other pc accessed the internet through this computer, both again using wireless to talk to each other.\n\nBeggar of a job, but possible.
909147
The only situation there is for placing a trap at the far end of an antenna, is if that antenna is part of a multi-band antenna system. For instance, you could put a trap at the end of a 1/4 wave 20m antenna (at about 16 ft), then connect the other side of it to an additional element, for 40m or 80m use.  If the antenna is for 160m, the only reason to have an extension is for BCB or LW coverage.  Is that what you're up to?  By the way, as already mentioned, the trap has to be used at a current peak (voltage node).
745937
On band radios I assume. There are many such sites on google.com that list them. Radio shack will also help you.
84334
See if your radio will take an external antenna.  If so, then grab some wire and string it around, and as high as you can.
224327
You can but u have to know some electronics for it...you can add abeat freq oscillator to receive ssb signals or attach a signal preamp at the antenna input to boost the reception and receive weaker stations or modify the mixer sections to change the receiving freq bandwidth.......possibilities are countless.
552633
This page is all about 6 meter antennas. http://members.fortunecity.com/xe1bef/6meters-antenna.htm It should help.
999979
The signal from the satellite is a microwave signal of a little more than a centimeter in wavelength. That means they will not pass through any metal with a hole smaller than that dimension, but instead are reflected. Microwaves are reflected from metal very much like light is reflected from metals. The satellite dish that appears to be plastic or fiberglass actually has metal embedded within it. Any type of metal, including copper, will work. The metal most commonly used is aluminum or steel.\n\nThe metal mesh is not used because of its conductive properties. Its conductivity is irrelevant. It is acting as a reflector and because of the parabolic shape of the dish is reflecting the signal in concentrated form into the receiver that sets over the front of the dish. \n\nI seriously doubt that any satellite dishes have silver in them, and using copper would be a waste of money, since copper is much more expensive than steel or aluminum. It is even possible to build a satellite dish out of chicken wire or screen wire. The wire is close enough together to reflect the microwaves. However, the shape is critical, and the plastic or fiberglass is designed to keep the critical shape. \n\nHere are some diagrams:\nhttp://www.mlesat.com/antennas.html\nThe microwave spectrum (in centimeters):\nhttp://meted.ucar.edu/npoess/microwave_topics/overview/print.htm#s1p2\nManufacture of dishes:\nhttp://www.madehow.com/Volume-1/Satellite-Dish.html
1160573
e-mail me: intel_knight-at-yahoo-dot-com\n\nAnd I have no clue how to build that EMP thing, or if it is even possible. I just thought it would be a cool thing to have.
561289
The answer is yes, and it's done all the time, for various reasons, and in various ways.\n\nThere are lots'a different satellite designs, depending on  the intended use. Steerable antenna beams can be designed to be moved either mechanically or electronically. \n\nAnd yes, sometimes the satellites are moved around in orbit, but not often.  Moving requires energy, and providing such energy, however it's done (and there are lots'a ways) is expensive in cost and payload.  \n\nYou asked a good question - you're a thinker! Hope this helps.\n\nGood luck!