Ghost Writer wrote:

Ah YES..... I'd LOVE to come up with a device to blow out those extra loud
car systems. HOW RIDICULOUS they are. Aside from such a device, the next
good idea is invest in any companies making hearing aids. They WILL be
JUMPING IN STOCK in about 5 years. Any names come to mind? I'd like to start
looking. G.W.

;-) Google for: hearing aid "Mel Tillis"

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In article , Wim Lewis
wrote:

In article ,
duckman wrote:
Had a question for open discussion

Is there available, can it be done to have an AM and/ and or FM transmitter
that will broadcast over the entire AM and FM broadcast band at the same
time. Or at least multiple stations. E.G.

Do you want to broadcast a large number of different signals simultaneously
from the same transmitter, or many copies of the same signal?

Both should be pretty straightforward to do... if you want to broadcast
many copies of the same signal, you could just replace the LO with
a circuit that generates a number of carriers, superimposed. Each
frequency component in the LO will produce a corresponding copy of the
audio signal in the RF or IF output.

I don't know if it's possible to broadcast a single audio signal spread
over a wide band (instead of having one copy at each standard AM station
frequency, as above). My intuition says it should be possible to
amplitude-modulate some wideband noise, and any AM receiver with an
envelope detector would recover the signal. But mathematically, I'm not
so sure --- where would the sidebands go, how would the receiver
distinguish them from the overlapping "carrier"? Or could this be
thought of as a sort of self-despreading spread spectrum signal?
Perhaps I should just go to bed ...





If you just want to jam, build a 10.7 MHz transmitter and turn it on when
desired. Most cheap radios don't have good IF rejection and the signal
will capture the normally weak incoming signal from the broadcast.
However, the whole thing is illegal no matter what the method.

Steve

In article , Wim Lewis
wrote:

In article ,
duckman wrote:
Had a question for open discussion

Is there available, can it be done to have an AM and/ and or FM transmitter
that will broadcast over the entire AM and FM broadcast band at the same
time. Or at least multiple stations. E.G.

Do you want to broadcast a large number of different signals simultaneously
from the same transmitter, or many copies of the same signal?

Both should be pretty straightforward to do... if you want to broadcast
many copies of the same signal, you could just replace the LO with
a circuit that generates a number of carriers, superimposed. Each
frequency component in the LO will produce a corresponding copy of the
audio signal in the RF or IF output.

I don't know if it's possible to broadcast a single audio signal spread
over a wide band (instead of having one copy at each standard AM station
frequency, as above). My intuition says it should be possible to
amplitude-modulate some wideband noise, and any AM receiver with an
envelope detector would recover the signal. But mathematically, I'm not
so sure --- where would the sidebands go, how would the receiver
distinguish them from the overlapping "carrier"? Or could this be
thought of as a sort of self-despreading spread spectrum signal?
Perhaps I should just go to bed ...





If you just want to jam, build a 10.7 MHz transmitter and turn it on when
desired. Most cheap radios don't have good IF rejection and the signal
will capture the normally weak incoming signal from the broadcast.
However, the whole thing is illegal no matter what the method.

Steve

On Tue, 09 Dec 2003 10:51:45 +1100, duckman wrote:

Had a question for open discussion

Is there available, can it be done to have an AM and/ and or FM transmitter
that will broadcast over the entire AM and FM broadcast band at the same
time. Or at least multiple stations. E.G.

From 88 - 108 at once or 88-98, then 98-108
Same on AM band.

It would have to be a low power to be able to be used on private property
and limiy range to 300 mtrs

Can this be done, where can l buy it, or how do l make it

Told you it was a dousy of a question, whats your thoughts.

Yes there are such animals out on the commercial market. It's often used
for emergency radio systems in tunnels ( like the Alp tunnels! ) Where you
have the need to send on all frequencies if something goes awry!

Mostly on the AM band but I think the same method is used for the FM band
as well. Ans yes, they use only one transmitter!

The basic principle is to take all available channels, 25 or 50 kc
separation. take the output
from all those channels and superimpose them on one signal carrier. The
resulting 'waveform' will then contain al channels and you just modulate
it and feed it to a broadband amplifier. For the AM broadband transmitter,
this is done by sampling the resulting signal and store it on an eprom
and use that as the input to generate a multifrequency signal.

Remember the old G3RUH modulation for 9600 baud, where its many
frequencies put together to generate the composite signal, which can be
taken apart by a receiver again.


Cheers

Sorry if this sounds weird, but if you wanna listen to the real case, just
drive down in the europe alp tunnels!

On Tue, 09 Dec 2003 10:51:45 +1100, duckman wrote:

Had a question for open discussion

Is there available, can it be done to have an AM and/ and or FM transmitter
that will broadcast over the entire AM and FM broadcast band at the same
time. Or at least multiple stations. E.G.

From 88 - 108 at once or 88-98, then 98-108
Same on AM band.

It would have to be a low power to be able to be used on private property
and limiy range to 300 mtrs

Can this be done, where can l buy it, or how do l make it

Told you it was a dousy of a question, whats your thoughts.

Yes there are such animals out on the commercial market. It's often used
for emergency radio systems in tunnels ( like the Alp tunnels! ) Where you
have the need to send on all frequencies if something goes awry!

Mostly on the AM band but I think the same method is used for the FM band
as well. Ans yes, they use only one transmitter!

The basic principle is to take all available channels, 25 or 50 kc
separation. take the output
from all those channels and superimpose them on one signal carrier. The
resulting 'waveform' will then contain al channels and you just modulate
it and feed it to a broadband amplifier. For the AM broadband transmitter,
this is done by sampling the resulting signal and store it on an eprom
and use that as the input to generate a multifrequency signal.

Remember the old G3RUH modulation for 9600 baud, where its many
frequencies put together to generate the composite signal, which can be
taken apart by a receiver again.


Cheers

Sorry if this sounds weird, but if you wanna listen to the real case, just
drive down in the europe alp tunnels!