Maker Pro
Maker Pro

broadcast audio signal

I was just wondering if you can broadcast an audio signal (100 Hz to
20 kHz) over the airwaves without upconverting it.

Are there any problems with doing this?
 
S

Stephen J. Rush

Jan 1, 1970
0
I was just wondering if you can broadcast an audio signal (100 Hz to
20 kHz) over the airwaves without upconverting it.

Are there any problems with doing this?

That's a huge bandwidth, about nine octaves. You can do it over short
ranges with magnetic coupling, but if you want more than a few feet of
range, upconverting to RF or modulated light is the only way to go.
 
P

Phil Allison

Jan 1, 1970
0
I was just wondering if you can broadcast an audio signal (100 Hz to
20 kHz) over the airwaves without upconverting it.



** Go look up "audio induction loop''.



....... Phil
 
J

jasen

Jan 1, 1970
0
I was just wondering if you can broadcast an audio signal (100 Hz to
20 kHz) over the airwaves without upconverting it.

Yes, It's done for hearing aids, it's called an inductive loop and has only
a short range.

Bye.
Jasen
 
E

Eeyore

Jan 1, 1970
0
I was just wondering if you can broadcast an audio signal (100 Hz to
20 kHz) over the airwaves without upconverting it.

Are there any problems with doing this?

Induction loop. That'll cover a modest area.

Graham
 
B

Bob Masta

Jan 1, 1970
0
I was just wondering if you can broadcast an audio signal (100 Hz to
20 kHz) over the airwaves without upconverting it.

Are there any problems with doing this?

If you actually want this to be an RF signal (in the
Extremely Low Frequency range) you will need the
mother of all antennas. IIRC, the US military (used to?)
use this range for communications with submerged
submarines. For a while they planned to use the
entire Upper Penninsula of Michigan as the
transmitting antenna, by virtue of its extensive iron
and copper deposits. The system was intended
for transmitting (at incredibly low bit rate) simple
nuclear missile launch instructions. There was a big flap over it
at the time (1980s maybe?), then we never heard
any more about it. Hopefully it died with the cold war.
But then again, one might have said that about the
Star Wars projects as well, and they seem to still be
with us....

Best regards,



Bob Masta

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Signal Generator
Science with your sound card!
 
D

default

Jan 1, 1970
0
I was just wondering if you can broadcast an audio signal (100 Hz to
20 kHz) over the airwaves without upconverting it.

Are there any problems with doing this?
They use induction loop systems for the hearing impaired in
auditoriums - big loop in the floor is modulated with the audio signal
and individual receivers pick up and amplify the signal. Better than
a hearing aid, because you don't amplify the ambient noise just the
program material.

Some folks used to put them in their houses for music and there might
be some info on the web how to go about it on a small scale.
 
T

Tom Biasi

Jan 1, 1970
0
I was just wondering if you can broadcast an audio signal (100 Hz to
20 kHz) over the airwaves without upconverting it.

Are there any problems with doing this?
How about a loudspeaker?
 
Top