CW Audio Filter
 

Is CW just FM without an audio signal? So, If I have a FM receiver, can I
install a CW audio filter and pick up CW. Such as... an IC 207H or BC 780xlt
and a Vectronics CW Audio Filter. Thanks
Matthew
KC2KEI
Scars are the proof that man can survive his own stupidity.

Matthew and Wendy Plante wrote:
Is CW just FM without an audio signal? So, If I have a FM receiver, can I
install a CW audio filter and pick up CW. Such as... an IC 207H or BC 780xlt
and a Vectronics CW Audio Filter. Thanks

FM receivers are designed to not respond to amplitude variations. CW is
about as pure an example of "information conveyed by variations in
amplitude" as one is likely to find. To cut to the chase, what you
propose won't work.

That being said, one can send Morse in a format receivable on an FM
receiver, but it'll be MCW rather than CW. Feeding a keyed audio
oscillator into an FM transmitter will produce MCW. The caveat here is
it is legal here in the states only from 50.1 to 54 MHz and above 144.1
MHz.

HTH

de kg7yy
--
The appearance of my E-mail address in any venue does not in and of itself
constitute a solicitation of bulk or commercial E-mail.

I don't want unsolicited commercial E-mail.

Matthew and Wendy Plante wrote:
Is CW just FM without an audio signal? So, If I have a FM receiver, can I
install a CW audio filter and pick up CW. Such as... an IC 207H or BC 780xlt
and a Vectronics CW Audio Filter. Thanks

FM receivers are designed to not respond to amplitude variations. CW is
about as pure an example of "information conveyed by variations in
amplitude" as one is likely to find. To cut to the chase, what you
propose won't work.

That being said, one can send Morse in a format receivable on an FM
receiver, but it'll be MCW rather than CW. Feeding a keyed audio
oscillator into an FM transmitter will produce MCW. The caveat here is
it is legal here in the states only from 50.1 to 54 MHz and above 144.1
MHz.

HTH

de kg7yy
--
The appearance of my E-mail address in any venue does not in and of itself
constitute a solicitation of bulk or commercial E-mail.

I don't want unsolicited commercial E-mail.

"Robert Grizzard" wrote in message
...
Matthew and Wendy Plante wrote:
Is CW just FM without an audio signal? So, If I have a FM receiver, can
I
install a CW audio filter and pick up CW. Such as... an IC 207H or BC
780xlt
and a Vectronics CW Audio Filter. Thanks

FM receivers are designed to not respond to amplitude variations. CW is
about as pure an example of "information conveyed by variations in
amplitude" as one is likely to find. To cut to the chase, what you
propose won't work.

That being said, one can send Morse in a format receivable on an FM
receiver, but it'll be MCW rather than CW. Feeding a keyed audio
oscillator into an FM transmitter will produce MCW. The caveat here is
it is legal here in the states only from 50.1 to 54 MHz and above 144.1
MHz.

HTH

de kg7yy
--
The appearance of my E-mail address in any venue does not in and of itself
constitute a solicitation of bulk or commercial E-mail.

I don't want unsolicited commercial E-mail.

So, If I had a receiver capable of AM reception, then a CW filter would
work?

"Robert Grizzard" wrote in message
...
Matthew and Wendy Plante wrote:
Is CW just FM without an audio signal? So, If I have a FM receiver, can
I
install a CW audio filter and pick up CW. Such as... an IC 207H or BC
780xlt
and a Vectronics CW Audio Filter. Thanks

FM receivers are designed to not respond to amplitude variations. CW is
about as pure an example of "information conveyed by variations in
amplitude" as one is likely to find. To cut to the chase, what you
propose won't work.

That being said, one can send Morse in a format receivable on an FM
receiver, but it'll be MCW rather than CW. Feeding a keyed audio
oscillator into an FM transmitter will produce MCW. The caveat here is
it is legal here in the states only from 50.1 to 54 MHz and above 144.1
MHz.

HTH

de kg7yy
--
The appearance of my E-mail address in any venue does not in and of itself
constitute a solicitation of bulk or commercial E-mail.

I don't want unsolicited commercial E-mail.

So, If I had a receiver capable of AM reception, then a CW filter would
work?

Hello

So, If I had a receiver capable of AM reception, then a CW filter would
work?

No, then you will need a beatoscillator.

No sound is transmitted when you use CW, the transmitter in only turned
on and off, so on a AM radio you only hear an interupted carrier and no
tone.

Regards Max

Hello

So, If I had a receiver capable of AM reception, then a CW filter would
work?

No, then you will need a beatoscillator.

No sound is transmitted when you use CW, the transmitter in only turned
on and off, so on a AM radio you only hear an interupted carrier and no
tone.

Regards Max

FM receivers are designed to not respond to amplitude variations. CW is
about as pure an example of "information conveyed by variations in
amplitude" as one is likely to find. To cut to the chase, what you
propose won't work.

Sure it will! Open the squelch up all the way. You'll hear the
background noise from the band and/or the front-end electronics when
there's no carrier being sent. When the OM at the other end keys up,
the FM receiver will lock onto the carrier, and happily demodulate the
(nonexistant) sidebands - it'll go silent. No CW filter needed... in
fact it'd make the noise/silence difference harder to hear.

Admittedly, trying to copy "negative noise" CW is likely to be a real
hassle at first, but I imagine that one can train oneself to do it
(just as one can train oneself to read a book held upside-down).

For _conventional_ CW reception, you need something rather different.

;-)

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

FM receivers are designed to not respond to amplitude variations. CW is
about as pure an example of "information conveyed by variations in
amplitude" as one is likely to find. To cut to the chase, what you
propose won't work.

Sure it will! Open the squelch up all the way. You'll hear the
background noise from the band and/or the front-end electronics when
there's no carrier being sent. When the OM at the other end keys up,
the FM receiver will lock onto the carrier, and happily demodulate the
(nonexistant) sidebands - it'll go silent. No CW filter needed... in
fact it'd make the noise/silence difference harder to hear.

Admittedly, trying to copy "negative noise" CW is likely to be a real
hassle at first, but I imagine that one can train oneself to do it
(just as one can train oneself to read a book held upside-down).

For _conventional_ CW reception, you need something rather different.

;-)

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Wed, 23 Jul 2003 11:38:14 GMT, "Matthew and Wendy Plante"
wrote:


"Robert Grizzard" wrote in message
...
Matthew and Wendy Plante wrote:
Is CW just FM without an audio signal? So, If I have a FM receiver, can
I
install a CW audio filter and pick up CW. Such as... an IC 207H or BC
780xlt
and a Vectronics CW Audio Filter. Thanks

FM receivers are designed to not respond to amplitude variations. CW is
about as pure an example of "information conveyed by variations in
amplitude" as one is likely to find. To cut to the chase, what you
propose won't work.

That being said, one can send Morse in a format receivable on an FM
receiver, but it'll be MCW rather than CW. Feeding a keyed audio
oscillator into an FM transmitter will produce MCW. The caveat here is
it is legal here in the states only from 50.1 to 54 MHz and above 144.1
MHz.

HTH

de kg7yy
--
The appearance of my E-mail address in any venue does not in and of itself
constitute a solicitation of bulk or commercial E-mail.

I don't want unsolicited commercial E-mail.

So, If I had a receiver capable of AM reception, then a CW filter would
work?


No, with AM reception, you'll just hear the CW signal as a staticky,
hashy sound. You need a receiver with a beat frequency oscillator, a
BFO, to receive CW with a nice tone.

The CW filter has nothing to do with receiving the CW signal, other
than narrowing the bandwidth to cut out interfering signals.

Bob
k5qwg