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Old January 3rd 04, 05:05 AM
Mike Coslo
 
Posts: n/a
Default How wide is a Moirse CW pulse?

The question kind of states it. I suppose that the BW might be wider as
the speed increases.

The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast. And it's some 700
kHz wide!!! And now I'd swear it's almost 3kHz wide. That's like SSB!!!

Needless to say, their strong signal was pretty tough on all us 5 and
ten watters. you could get most of a message through, but it took a lt
of the fun out of it.

What the heck , over?

- Mike KB3EIA -

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Old January 3rd 04, 02:56 PM
N2EY
 
Posts: n/a
Default

In article , Mike Coslo
writes:

The question kind of states it. I suppose that the BW might be wider as
the speed increases.


Mike,

The bandwidth of a Morse signal is determined by the rise and fall times of the
leading and trailing edges of each dit or dah, and the shape of the rise and
fall.


The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast.


Who is "we", Mike?

And it's some 700
kHz wide!!!


How did you determine the bandwidth?

And now I'd swear it's almost 3kHz wide. That's like SSB!!!


Yep. Such a bandwidth would require extremely "hard" keying, though. Or a
modulated carrier.

Needless to say, their strong signal was pretty tough on all us 5 and
ten watters. you could get most of a message through, but it took a lt
of the fun out of it.


Was the AGC on?

73 de Jim, N2EY

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Old January 3rd 04, 03:06 PM
Bert Craig
 
Posts: n/a
Default

Mike Coslo wrote in message t...
The question kind of states it. I suppose that the BW might be wider as
the speed increases.


Mike, I believe the bandwidth actually decreases as the speed increases.

The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast. And it's some 700
kHz wide!!! And now I'd swear it's almost 3kHz wide. That's like SSB!!!

Needless to say, their strong signal was pretty tough on all us 5 and
ten watters. you could get most of a message through, but it took a lt
of the fun out of it.


Bummer, hope it was just a one-time anomaly.

What the heck , over?

- Mike KB3EIA -


73 de Bert
WA2SI
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Old January 3rd 04, 03:19 PM
Carl R. Stevenson
 
Posts: n/a
Default

Mike,

Sounds to me like you were experiencing front end overload in your
receiver ... when the signal exceeds the dynamic range of your receiver,
all sorts of things happen and the signal can appear to be MUCH wider
than it actually is.

To verify this, turn off the preamp (if you have one), and switch in about
20 dB of attenuation before the front end of the receiver and see if it
all gets better ...

73,
Carl - wk3c

"Mike Coslo" wrote in message
...
The question kind of states it. I suppose that the BW might be wider as
the speed increases.

The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast. And it's some 700
kHz wide!!! And now I'd swear it's almost 3kHz wide. That's like SSB!!!

Needless to say, their strong signal was pretty tough on all us 5 and
ten watters. you could get most of a message through, but it took a lt
of the fun out of it.

What the heck , over?

- Mike KB3EIA -


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Old January 3rd 04, 05:02 PM
Keyboard In The Wilderness
 
Posts: n/a
Default

From the ARRL License Manual 1976:
CW Bandwidth = wpm X 4 (e.g., 40 WPM = 160 Hz)
"With proper shaping, the necessary keying bandwidth is equal to 4
times the speed in words per minute for International Morse Code;
e.g. at 25 words per minute, the bandwidth is approximately 100 cycles."

--
73 From The Wilderness Keyboard
==================================
"Mike Coslo" wrote in message
...
The question kind of states it. I suppose that the BW might be wider as
the speed increases.

The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast. And it's some 700
kHz wide!!! And now I'd swear it's almost 3kHz wide. That's like SSB!!!

Needless to say, their strong signal was pretty tough on all us 5 and
ten watters. you could get most of a message through, but it took a lt
of the fun out of it.

What the heck , over?

- Mike KB3EIA -





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Old January 3rd 04, 05:08 PM
Keyboard In The Wilderness
 
Posts: n/a
Default


From the ARRL License Manual 1976:
CW Bandwidth = wpm X 4 (e.g., 40 WPM = 160 Hz)
"With proper shaping, the necessary keying bandwidth is equal to 4
times the speed in words per minute for International Morse Code;
e.g. at 25 words per minute, the bandwidth is approximately 100 cycles."

Also -- suspect your receiver bandwidth and dynamic range -- try some
attenuation and reduce RF gain or Kenwoods AIP -- helps with strong adjacent
signals.

73 From The Wilderness Keyboard
==================================
"Mike Coslo" wrote in message
...
The question kind of states it. I suppose that the BW might be wider as
the speed increases.

The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast. And it's some 700
kHz wide!!! And now I'd swear it's almost 3kHz wide. That's like SSB!!!

Needless to say, their strong signal was pretty tough on all us 5 and
ten watters. you could get most of a message through, but it took a lt
of the fun out of it.

What the heck , over?

- Mike KB3EIA -





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Old January 3rd 04, 05:12 PM
Bill Sohl
 
Posts: n/a
Default


"Mike Coslo" wrote in message
...
The question kind of states it. I suppose that the BW might be wider as
the speed increases.

The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast. And it's some 700
kHz wide!!! And now I'd swear it's almost 3kHz wide. That's like SSB!!!


Did you mean 700Hz wide (you typed 700kHz).

Cheers,
Bill K2UNK





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Old January 3rd 04, 07:04 PM
Dan/W4NTI
 
Posts: n/a
Default


"N2EY" wrote in message
...
In article , Mike Coslo
writes:

The question kind of states it. I suppose that the BW might be wider as
the speed increases.


Mike,

The bandwidth of a Morse signal is determined by the rise and fall times

of the
leading and trailing edges of each dit or dah, and the shape of the rise

and
fall.


The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast.


Who is "we", Mike?

And it's some 700
kHz wide!!!


How did you determine the bandwidth?

And now I'd swear it's almost 3kHz wide. That's like SSB!!!


Yep. Such a bandwidth would require extremely "hard" keying, though. Or a
modulated carrier.

Needless to say, their strong signal was pretty tough on all us 5 and
ten watters. you could get most of a message through, but it took a lt
of the fun out of it.


Was the AGC on?

73 de Jim, N2EY


Part of the equation here is the receiver, as Jim N2EY was bringing up. A
lot of folks don't understand that actual bandwidth and apparant bandwith as
determined by a receiver are not the same in most cases.

Also I really don't see the problem, why did you just sit there? Were you
all rock bound or what?

Move frequency, were not channelized, yet.

Dan/W4NTI


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Old January 3rd 04, 07:06 PM
Dan/W4NTI
 
Posts: n/a
Default


"Bert Craig" wrote in message
om...
Mike Coslo wrote in message

t...
The question kind of states it. I suppose that the BW might be wider as
the speed increases.


Mike, I believe the bandwidth actually decreases as the speed increases.

The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast. And it's some 700
kHz wide!!! And now I'd swear it's almost 3kHz wide. That's like SSB!!!

Needless to say, their strong signal was pretty tough on all us 5 and
ten watters. you could get most of a message through, but it took a lt
of the fun out of it.


Bummer, hope it was just a one-time anomaly.

What the heck , over?

- Mike KB3EIA -


73 de Bert
WA2SI


A one time anomaly????? W1AW is a bulletin station. Been there, on or
about for 90 years.

Dan/W4NTI


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Old January 3rd 04, 08:44 PM
Mike Coslo
 
Posts: n/a
Default



N2EY wrote:

In article , Mike Coslo
writes:


The question kind of states it. I suppose that the BW might be wider as
the speed increases.



Mike,

The bandwidth of a Morse signal is determined by the rise and fall times of the
leading and trailing edges of each dit or dah, and the shape of the rise and
fall.


The reason I ask is that on 3580 tonight, we're all sitting there fat,
dumb, and happy, when W1AW starts it's CW broadcast.



Who is "we", Mike?


Just a number of Hams using PSK31. I was only monitoring, so I didn't
keep track of callsigns.

And it's some 700
kHz wide!!!



How did you determine the bandwidth?


On the waterfall display, you can look at the BW pretty directly. A good
psk31 signal doesn't take up a whole lot of space, maybe 40 hz.

This CW signal had spikes on the end that extended almost 400 hz on
each side. It ripped into the PSK signal and wiped it out. When it got
really bad, everyone just gave up.

And now I'd swear it's almost 3kHz wide. That's like SSB!!!



Yep. Such a bandwidth would require extremely "hard" keying, though. Or a
modulated carrier.

Needless to say, their strong signal was pretty tough on all us 5 and
ten watters. you could get most of a message through, but it took a lt
of the fun out of it.



Was the AGC on?


Both on and off. I often have to turn it off when a strong signal
desenses the reciever and I'm working a weak station.

Your modulated carrier thing may just be a big clue. When the signal
ended up putting spikes over the whole section of the band, I removed
the connection to the computer to listen to the signal. It sounded
pretty strange. I'll have to check what the signal again to see what it
sounds like on ssb or even AM.

But in these K1MAN days, it would be a good idea for ARRL to keep a
good clean signal, and not do the eqivelant of K1MAN - that is to just
start the transmission and stomp all over everyone else nearby.



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