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.

In article , Mike Coslo
writes:

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.

A Morse signal set up for optimal BW at 50 wpm takes up about 200 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.

Key clicks. Could be caused by a problem at Newington, or by a problem at the
receiver end.

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.

But did you also turn down the RF gain and turn up the AF? Or kick in an
attenuator?

What WK3C posted earlier is correct - if a strong signal overloads your
receiver, its bandwidth may appear to be wider than it really is. If someone is
running PSK31 using the usual SSB-rig-feeding-a-soundcard approach, overload of
the receiver is a real possibility.

What was your setup?

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.

Sure.

btw, W1AW's 80m CW freq is advertised as 3581.5 IIRC.

Oddly enough, last night I was "reading the mail" from W1AW on 40 meters while
packing up some parts I sold. Signal was very clean on my Southgate Type 7. I'm
not sure of the exact time, but the transmission ended with "END OF 35 WPM" ;-)


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.

The transmitters at W1AW are all Harris "professional grade" transceivers, one
for each band plus a spare. Computer controlled from the main console, no
adjustments needed to the rig itself. But even Harris stuff can have problems.

Separate antennas for each band, too - the 80/75 antenna is a cage dipole
between two of the towers. 80 feet up if it's a foot.

I'll tune down to 80 tonight if I get the chance and see how W1AW sounds.

73 de Jim, N2EY