Signal Generator as a AM Transmitter?

9/15/2000 9:38:49 PMJIm

I've heard that a signal generator can be used to transmit a signal from a CD player, etc to a Am radio.
Can someone give me detailed information on how to set one up to do this?

Thanks, Jim

9/15/2000 10:39:32 PMNorm Leal

Hi Jim

Interesting - Yes a signal generator can be used this way. It generates a RF signal that can be adjusted to frequencies across the broadcast band.

The only thing left to do is modulate the RF signal with your CD player.. Look for an input on the signal generator where you can connect and external signal to modulate the RF signal.. Connect the CD player output to this connector and the Signal Generator will act like a small transmitter.

Norm

: I've heard that a signal generator can be used to transmit a signal from a CD player, etc to a Am radio.
: Can someone give me detailed information on how to set one up to do this?

: Thanks, Jim

9/18/2000 1:08:25 AMDean Huster

Hello, Jim,

I've done this a lot, but with lab-quality generators. You can have problems if you're not careful with low-cost signal generators because they do not output a pure sine wave and are loaded with all kinds of harmonics that could interfere with radio reception at many different frequencies simultaneously, especially if you decide to stretch out a long antenna. Many generators are capable of putting out a signal as high as 3 volts RMS and with a long-wire antenna, can radiate a signal anywhere from several blocks up to a few miles. Enough consistent operation with a lousy signal can get the neighbors a little irritated and consequently get the FCC involved.

My advice is, if you use a low-cost signal generator (or any generator for that matter), keep the antenna length no longer than is necessary to get the signal to your radio. And don't forget that you'll have to mix the left and right channels from your CD player down to a single channel for modulating the signal generator.

Dean

9/18/2000 9:50:17 AMdavep

Antique Tv people can have fun with and old VCR and a 20 db coax amp from Radio-Slack..
It goes like this: [VCR out]---->[20db in line coax amp]------>[ antenna] ..select channel 3 or 4..

The antenna is critical to to operation. Throwing any math to the wind ( takes the fun out of it, doesnt it?), i tried several lengths of wire, which should be quite short and moved them around to various vectors and shapes. needless to say pointing at the tv seems to bring the best picture. As for distance, i moved it about 25 feet away and still had audio and "ghosts" so that would be around maximum..
Not a bad picture at all within 10 feet with the proper antenna.

I saw how to do this from another website which escapes me now, but it will work and you can amaze your friends with some old kinescope recordings if they arent aware of your hijinx.
dave

: Hello, Jim,

: I've done this a lot, but with lab-quality generators. You can have problems if you're not careful with low-cost signal generators because they do not output a pure sine wave and are loaded with all kinds of harmonics that could interfere with radio reception at many different frequencies simultaneously, especially if you decide to stretch out a long antenna. Many generators are capable of putting out a signal as high as 3 volts RMS and with a long-wire antenna, can radiate a signal anywhere from several blocks up to a few miles. Enough consistent operation with a lousy signal can get the neighbors a little irritated and consequently get the FCC involved.

: My advice is, if you use a low-cost signal generator (or any generator for that matter), keep the antenna length no longer than is necessary to get the signal to your radio. And don't forget that you'll have to mix the left and right channels from your CD player down to a single channel for modulating the signal generator.

: Dean

9/18/2000 3:43:57 PMDean Huster

Hi, Dave,

When the Atari's and such first came out, that was why they included the little antenna switch box, so that folks wouldn't just hook the video game to the same antenna terminals to which the antenna was connected. Turned your house into a little broadcasting station and the neighbors didn't necessarily liked watching a snowy version of Pacman on their TV. Worse yet, if folks hooked up a VCR by connecting the RF out to the TV antenna input while the antenna was still connected, it was found that there were cases where someone found out what their neighbors looked like without clothing during their "amateur video camera" nights. Gotta be careful sometimes.

Dean

9/19/2000 1:45:25 AMdavep

:
: Hi, Dave,

: When the Atari's and such first came out, that was why they included the little antenna switch box, so that folks wouldn't just hook the video game to the same antenna terminals to which the antenna was connected. Turned your house into a little broadcasting station and the neighbors didn't necessarily liked watching a snowy version of Pacman on their TV. Worse yet, if folks hooked up a VCR by connecting the RF out to the TV antenna input while the antenna was still connected, it was found that there were cases where someone found out what their neighbors looked like without clothing during their "amateur video camera" nights. Gotta be careful sometimes.

: Dean

A little modulation can be a dangerous thing!
have a great evening dean.
davep

8/11/2001 8:28:53 AMdhin

: Hello, Jim,

: I've done this a lot, but with lab-quality generators. You can have problems if you're not careful with low-cost signal generators because they do not output a pure sine wave and are loaded with all kinds of harmonics that could interfere with radio reception at many different frequencies simultaneously, especially if you decide to stretch out a long antenna. Many generators are capable of putting out a signal as high as 3 volts RMS and with a long-wire antenna, can radiate a signal anywhere from several blocks up to a few miles. Enough consistent operation with a lousy signal can get the neighbors a little irritated and consequently get the FCC involved.

: My advice is, if you use a low-cost signal generator (or any generator for that matter), keep the antenna length no longer than is necessary to get the signal to your radio. And don't forget that you'll have to mix the left and right channels from your CD player down to a single channel for modulating the signal generator.

: Dean