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!