FM multiple frequency broadcasting

H

Hans jkfa

Guest
I am looking for investigating if it is possible to buy a multi
frequency FM transmitter. I want to broadcast a FM signal out on the
whole range of 87.5-108 MHz. i want the output to be limited to about
a couple of hundred meters of diameter, does anyone have a clue if
that is possible ?

Ive read about some PCI cards you can buy for your PC which should
have a really powerfull output (i think about 15 kW) does anyone know
if there are some cards which can broadcast on multiple frequencys'

Thx Nichlas
 
Hans jkfa wrote:
I am looking for investigating if it is possible to buy a multi
frequency FM transmitter. I want to broadcast a FM signal out on the
whole range of 87.5-108 MHz. i want the output to be limited to about
a couple of hundred meters of diameter, does anyone have a clue if
that is possible ?

Ive read about some PCI cards you can buy for your PC which should
have a really powerfull output (i think about 15 kW) does anyone know
if there are some cards which can broadcast on multiple frequencys'

Thx Nichlas
Click to expand...
I'm not _sure_, but if you're in the U.S., this sounds like something
which the Federal Communications Commission (FCC) would NOT like, and
would be knocking on your door shortly after you power up.

I suspect you wouldn't be popular with similar agencies in the U.K. and
the rest of the E.U., or in Japan or any other industrialized /
developed nation.

And 15 _kilowatts_ out of a card you plug into your PC???

Bob Pownall
 
Hans jkfa wrote:

I am looking for investigating if it is possible to buy a multi
frequency FM transmitter. I want to broadcast a FM signal out on the
whole range of 87.5-108 MHz. i want the output to be limited to about
a couple of hundred meters of diameter, does anyone have a clue if
that is possible ?

Ive read about some PCI cards you can buy for your PC which should
have a really powerfull output (i think about 15 kW) does anyone know
if there are some cards which can broadcast on multiple frequencys'

Thx Nichlas
Nice one.
Click to expand...
Grudge match?
 
On Sun, 9 Aug 2009 14:16:23 -0700 (PDT), Hans jkfa
<lortefirewallregler@gmail.com> wrote:

I am looking for investigating if it is possible to buy a multi
frequency FM transmitter. I want to broadcast a FM signal out on the
whole range of 87.5-108 MHz. i want the output to be limited to about
a couple of hundred meters of diameter, does anyone have a clue if
that is possible ?
Click to expand...
Please note that you can only transmit on one 200kHz wide channel at a
time. Dominating the entire FM broadcast band is not a good idea. If
you want "multiple frequency broadcasting", you'll need multiple
transmitters.

For only a few hundred meters, you can do it without a license.
<http://www.ramseyelectronics.com/hk/default.asp?page=amfm>

If you want to go the licensed route:
<http://en.wikipedia.org/wiki/LPFM>
<http://www.fcc.gov/lpfm/>

Ive read about some PCI cards you can buy for your PC which should
have a really powerfull output (i think about 15 kW) does anyone know
if there are some cards which can broadcast on multiple frequencys'
Click to expand...
15 kilowatts on a PCI card is rather improbable. For FM broadcast,
there's really no reason why you would want the xmitter on a PCI card
since there's nothing that really involves a computer in the
transmitter.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 
On Sun, 09 Aug 2009 17:27:59 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

15 kilowatts on a PCI card is rather improbable. For FM broadcast,
there's really no reason why you would want the xmitter on a PCI card
since there's nothing that really involves a computer in the
transmitter.
Click to expand...
Of course, that doesn't mean someone hasn't done it:
<http://www.electrokits.com/radio/fm-transmitters/185.htm>
<http://www.pcs-electronics.com/pc-transmitters-c-64.html>
Made for listening to MP3's on an FM receiver.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 
Jeff Liebermann wrote:
On Sun, 09 Aug 2009 17:27:59 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

15 kilowatts on a PCI card is rather improbable. For FM broadcast,
there's really no reason why you would want the xmitter on a PCI card
since there's nothing that really involves a computer in the
transmitter.

Of course, that doesn't mean someone hasn't done it:
http://www.electrokits.com/radio/fm-transmitters/185.htm
http://www.pcs-electronics.com/pc-transmitters-c-64.html
Made for listening to MP3's on an FM receiver.
Click to expand...
NOTE: DO NOT TRY THIS AT HOME! FCC WILL NOT LIKE!

Just a thought ... what is the feasibility of transmitting on the IF
frequency (commonly 10.7 MHz)?

You would have to take great care to have a well-filtered signal
(passing the signal through plain old ceramic filters) and have *very*
low output power, just enough to capture the intended receiver.

This because of the other users of that frequency band, and because of
the of the propagation of 10.7 MHz frequencies.

Of course, this means the range would be in the range of meters rather
hundreds of meters, and the receivers may have to be 'prepped' by adding
some form of antenna to the IF system (which in turn has to be designed
in a proper way to prevent leakage of IF frequencies from the receivers
mixer).

I'm asking this, not so much because of the OP's question but because
I've been toying with the concept at times, as means of a 'Emergency
Broadcast System' for fire and/or evacuation alarms.

I could also see law enforcement applications for such a transmitter,
like being used in parallel with the PA found on most cars, or as a
diversion when doing a raid on some place.

Any more thoughts?

/T.

--
Teodor Väänänen | Don't meddle in the affairs of wizards,
<teostupiditydor@algonet.se> | for you are good and crunchy with
http://www.algonet.se/~teodor/ | ketchup.
Remove stupidity to reply. |
 
Jeff Liebermann wrote:
On Sun, 09 Aug 2009 17:27:59 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

15 kilowatts on a PCI card is rather improbable. For FM broadcast,
there's really no reason why you would want the xmitter on a PCI card
since there's nothing that really involves a computer in the
transmitter.

Of course, that doesn't mean someone hasn't done it:
http://www.electrokits.com/radio/fm-transmitters/185.htm
http://www.pcs-electronics.com/pc-transmitters-c-64.html
Made for listening to MP3's on an FM receiver.
Click to expand...
NOTE: DO NOT TRY THIS AT HOME! FCC WILL NOT LIKE!

Just a thought ... what is the feasibility of transmitting on the IF
frequency (commonly 10.7 MHz)?

You would have to take great care to have a well-filtered signal
(passing the signal through plain old ceramic filters) and have *very*
low output power, just enough to capture the intended receiver.

This because of the other users of that frequency band, and because of
the of the propagation of 10.7 MHz frequencies.

Of course, this means the range would be in the range of meters rather
hundreds of meters, and the receivers may have to be 'prepped' by adding
some form of antenna to the IF system (which in turn has to be designed
in a proper way to prevent leakage of IF frequencies from the receivers
mixer).

I'm asking this, not so much because of the OP's question but because
I've been toying with the concept at times, as means of a 'Emergency
Broadcast System' for fire and/or evacuation alarms.

I could also see law enforcement applications for such a transmitter,
used in parallel with the
--
Teodor Väänänen | Don't meddle in the affairs of wizards,
<teostupiditydor@algonet.se> | for you are good and crunchy with
http://www.algonet.se/~teodor/ | ketchup.
Remove stupidity to reply. |
 
Jeff Liebermann wrote:
On Sun, 09 Aug 2009 17:27:59 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

15 kilowatts on a PCI card is rather improbable. For FM broadcast,
there's really no reason why you would want the xmitter on a PCI card
since there's nothing that really involves a computer in the
transmitter.

Of course, that doesn't mean someone hasn't done it:
http://www.electrokits.com/radio/fm-transmitters/185.htm
http://www.pcs-electronics.com/pc-transmitters-c-64.html
Made for listening to MP3's on an FM receiver.
Click to expand...
NOTE: DO NOT TRY THIS AT HOME! FCC WILL NOT LIKE!

Just a thought ... what is the feasibility of transmitting on the IF
frequency (commonly 10.7 MHz)?

You would have to take great care to have a well-filtered signal
(passing the signal through plain old ceramic filters) and have *very*
low output power, just enough to capture the intended receiver.

This because of the other users of that frequency band, and because of
the of the propagation of 10.7 MHz frequencies.

Of course, this means the range would be in the range of meters rather
hundreds of meters, and the receivers may have to be 'prepped' by adding
some form of antenna to the IF system (which in turn has to be designed
in a proper way to prevent leakage of IF frequencies from the receivers
mixer).

I'm asking this, not so much because of the OP's question but because
I've been toying with the concept at times, as means of a 'Emergency
Broadcast System' for fire and/or evacuation alarms.

I could also see law enforcement applications for such a transmitter,
used in parallel with the
--
Teodor Väänänen | Don't meddle in the affairs of wizards,
<teostupiditydor@algonet.se> | for you are good and crunchy with
http://www.algonet.se/~teodor/ | ketchup.
Remove stupidity to reply. |
 
Jeff Liebermann wrote:
On Sun, 09 Aug 2009 17:27:59 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

15 kilowatts on a PCI card is rather improbable. For FM broadcast,
there's really no reason why you would want the xmitter on a PCI card
since there's nothing that really involves a computer in the
transmitter.

Of course, that doesn't mean someone hasn't done it:
http://www.electrokits.com/radio/fm-transmitters/185.htm
http://www.pcs-electronics.com/pc-transmitters-c-64.html
Made for listening to MP3's on an FM receiver.
Click to expand...
NOTE: DO NOT TRY THIS AT HOME! FCC WILL NOT LIKE!

Just a thought ... what is the feasibility of transmitting on the IF
frequency (commonly 10.7 MHz)?

You would have to take great care to have a well-filtered signal
(passing the signal through plain old ceramic filters) and have *very*
low output power, just enough to capture the intended receiver.

This because of the other users of that frequency band, and because of
the of the propagation of 10.7 MHz frequencies.

Of course, this means the range would be in the range of meters rather
hundreds of meters, and the receivers may have to be 'prepped' by adding
some form of antenna to the IF system (which in turn has to be designed
in a proper way to prevent leakage of IF frequencies from the receivers
mixer).

I'm asking this, not so much because of the OP's question but because
I've been toying with the concept at times, as means of a 'Emergency
Broadcast System' for fire and/or evacuation alarms.

I could also see law enforcement applications for such a transmitter,
used in parallel with the PA of the police car, or as a diversionary
tactic during raids.

/T.
--
Teodor Väänänen | Don't meddle in the affairs of wizards,
<teostupiditydor@algonet.se> | for you are good and crunchy with
http://www.algonet.se/~teodor/ | ketchup.
Remove stupidity to reply. |
 
In article <8f2e0df7-8ae5-4bac-8fa7-8f2f19c7904a@z28g2000vbl.googlegroups.com>,
Hans jkfa <lortefirewallregler@gmail.com> wrote:

I am looking for investigating if it is possible to buy a multi
frequency FM transmitter. I want to broadcast a FM signal out on the
whole range of 87.5-108 MHz. i want the output to be limited to about
a couple of hundred meters of diameter, does anyone have a clue if
that is possible ?
Click to expand...
There is a way to do this: pick an on channel frequency in the center
of the band and AM modulate the FM signal with a short duty cycle pulse
at 200 kHz, (the channel spacing). A multitude of side bands, all with
your audio mixed in. And, as the power gets quite low as the pulsed
signal has a low duty cycle, you'd have to raise the peak power to the
point where YOU WILL GET NOTICED.

This will guarantee that you'll get your butt kicked by the FAA (or
whatever your local aviation authority is) , as the band above the FM band
is used for the VOR radio-direction finding system used for air navigation.
Jamming broadcasters is one thing, risking lives is another. If they
have problems, they don't just send a car around a few weeks from now,
they send up an airplane and find what's going on. (Well, I hope they
still do. You never know, with the way they run things now).

In the US, a couple of hundred meters is a bit over the limit
(250 uV/M at 1 meter or something like that). I worked that out
as 30-50 nanowatts radiated. Good for about 50 yards or so with
a good radio. And only one 200 kHz wide signal at a time.

Mark Zenier mzenier@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)
 
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