| Author | Message | ||
     Anonymous |
I have tried as hard as I could to transmit video through the AM transmitter, but it never worked. Is there any way I can accomplish this? | ||
| Anonymous |
I have tried transmitting from the RCA jacks in a camcorder, but the signal on the TV is blank. | ||
| Simon Quellen Field (Sfield) |
Back in the old days, video games came with a device called an RF Modulator. It was a cheap and simple AM transmitter for video, often just a single chip. You connected it to the antenna input of the TV. You put video in, and the TV showed it. I connected a VCR to an RF modulator, and then out the output of that into a 30dB video distribution amplifier from Radio Shack, and put the output of that into a set of rabbit ears for an antenna. The signal could show on the TV from several feet away, getting noisier as the distance grew. You can buy an RF modulator from these guys for $13. There is a circuit here. A one-chip version is here. Do a Google search for "video rf modulator" and "video rf modulator circuit". There are thousands of sites with the information you want. | ||
| alex oneill |
why dont you try buying a wireless fm microphone(the kind that has a separete plug in mic included) 2 rca>phono adapters, and a cheap fm raido(the tiny super cheap ones) Connect the first rca>phono adapter into the tranmitter and connest the rca end to the output device(i.e. camcorder,vcr) via an rca cable. connect the other rca>phono adapter to the cheap radio and to the tv via an rca cable now tune the radio to the transmitters freqency while the tv and the output device is on when you get a picture, you have the right frequency | ||
| Simon Quellen Field (Sfield) |
Television signals have a 3.5 Mhz bandwidth. FM radio has a 0.044 Mhz bandwidth. You can't put 10 pounds of sand in a 5 pound bag. The RF modulator from a video game is designed to send television signals, and is cheaper than the FM transmitter. | ||
| alex o'neill Unregistered guest |
this is kind of going off topic,but when are you going to introduce some new projects?I am dying for some(new projects) | ||
| lysdexia Unregistered guest |
Yes you can, by changing the rules... | ||
| Prem Thomas Unregistered guest |
Hey i am making a project to try and send signals from a remote controlled car to a computer screen?? Do any of you think that this possible?? Could you link me up to a few sites?? premthomas gmail.com | ||
| Simon Quellen Field (sfield) New member Username: sfield Post Number: 109 Registered: 12-2004 |
Do a Google search for "video transmitter" and buy a small battery operated transmitter designed for video. I would suggest getting one that uses cable channel 58 or 59. Then you can use a regular TV to receive it, or a TV card in your computer to get the picture on the screen. | ||
| Anonymous |
Theoretically, couldn't one just attach one of the yello RCA plugs to a radio and trasmit it? Isn't the signal the same as a radio? Why does one need a modulator? I truly don't know very much on the topic, so excuse any ignorance. LBS | ||
| Simon Quellen Field (sfield) New member Username: sfield Post Number: 141 Registered: 12-2004 |
Read carefully the entire Radio chapter. It will tell you the answer in detail. The simple version is that if you did what you suggest, there could only be one television channel in the whole world, since from 0 to 4 Mhz would be used by your station, so no one else could use it. By placing the video signal on a carrier up at 50 Mhz, and another one at 54, etc., we can have many different signals on the air at a time, and decide which one we want to watch by switching between channels. Also, the 0 to 4 Mhz frequencies are in use by other communications services, such as AM radio. | ||
| Hendrix00 Unregistered guest |
i am trying to use a transmitter and a reciever from a remote control car and controller to transmit video from a mini 9-volt camera from supercircuits.com. will that work? | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 511 Registered: 12-2004 |
No. Video signals are 3.5 megahertz wide. The remote control is about 10 khz wide. If you put video signals into it, you will be splattering your signal from 27 Mhz up to 30.5 Mhz, while all of the 40 channels in the entire 11 meter band only go from 26.965 to 27.405 Mhz. The only thing preventing you from interfering with the entire 11 meter band and most of the 10 meter Amateur Radio band is the filtering on the output of the remote control, which is supposed to limit you to your 10 khz width. The receiver on the remote is narrowband, and will not receive the wideband video signal anyway. | ||
| Mark Coelho (Unregistered Guest) Unregistered guest Posted From: 147.226.206.184 |
This thread looks kinda dead, but what about transmiting USB signals? (wireless webcam) I don't really know what I'm taking about, i just tend to try things and get lucky all too often.  However, couldn't you use a 900mhz cordless phone to transmit video using the base station as a reciever? | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 783 Registered: 12-2004 |
The problem is bandwidth. The 900 Mhz phone has channels that are on the order of 3 to 4 kilohertz wide. Video needs roughly a thousand times that bandwidth (3.5 Mhz channels). | ||
| justine aquino (Unregistered Guest) Unregistered guest Posted From: 202.78.104.119 |
something you might realy want to try! Is it possible to drive a motor using a germanium detector?because i would like to make an r/c using the following items: 1) 28.000 mhz oscillator 2) germanium diode 3) computer 4) some wire 5) solder(and solder wire) 6) motor(that runs on 1.2 volts) 7) and a printed circuit board i just want to know "if" it is possible to make it working. thanks for giving ispiration on this site.(its the only web site that has this kinds of explantions,...that i know)if you have a suggested web site pls be very kind to e-mail me at arklite_caim@yahoo.com (if you want to know where i got those names,...its a long story,but,you'll understand if your a kid! =)..) | ||
| alex oneill (Alex_oneill) New member Username: Alex_oneill Post Number: 1 Registered: 6-2005 |
thats a thought...if you could amplify the sgnal enough, you could,in theroy, drive a motor, maybe a light or two...just a passing thought...hmm..simon...do you think a one watt amplifier or two or 3 in series could handle it with enough power...i think i posted this once elswhere...who knows...that was a year ago | ||
| Troy (Pharoah) Member Username: Pharoah Post Number: 17 Registered: 3-2006 |
You could build a mechanical television I have always wanted to do this, and they are very low bandwidth. Look up "NBTV" on google | ||
| Thomas Vlaskamp (Vlasktom) New member Username: Vlasktom Post Number: 1 Registered: 10-2006 |
There's one HUGE problem with trying to broadcast video, and that's the FCC, if you're in the US... If the broadcast is farther than 1/4 mile, the FCC will get mad, and shut you down... until you get your $100 license that has to be renenwed every now and then... it's a good idea, but research goes a long way. If I burst your bubble, i'm sorry. | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 1541 Registered: 12-2004 |
The license fee is $14 in the U.S. It's good for 10 years, and is renewable for free. You can renew using a web form. Since full-speed television generally uses frequencies that are not reflected by the ionosphere, the distance is the same as any commercial television station -- i.e. pretty much line-of-sight. If you can see the antenna with a telescope, you can pick up the signal. This is why television antenna towers are located on mountaintops where possible. I live on a mountaintop, and occasionally transmit video. My signals have been received 40 miles away. | ||
| Thomas Vlaskamp (Vlasktom) Junior Member Username: Vlasktom Post Number: 5 Registered: 10-2006 |
I was transmitting using low power, less than 10 watts... the signal was picked up all the way in Indianapolis, about 100 miles away... I was transmitting on a channel that was in use by a station in Terre Haute, and was being simulcasted on cable in Indy. The FCC tracked the source, and shut me down. I didn't have the money to buy the license, so they shut me down for good. Oh, and the power source of a 9-volt battery would only spit out maybe about 10 feet or so, so the am transmitter isn't a good video transmitter. It's a good starting place, but not a perminant transmitter. | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 1545 Registered: 12-2004 |
A license only costs $14. You should not have been transmitting on someone else's frequency. | ||
| jonti olds (Jontio) New member Username: Jontio Post Number: 1 Registered: 4-2007 |
I have managed relatively good quality narrowband video/audio from one end of my house to the other using a program I made. I used a little commercial FM band transmitter (50kHz bandwidth). I used about 20 kHz of bandwidth. It uses the soundcard on my computer to modulate in QAM64. I get a data bit rate of 80kbs so the picture quality is better than that over dialup modem. As for longer distances I’ve yet to test this. I know with longer distances I’ll get a multipath problem, but I don’t know just how much of a problem it’ll be. Something still to do. If you want to try it yourself go to http://homepages.paradise.net.nz/peterfr2/QAM.htm It’s pretty untested and no manual. |
