On 3/30/2016 12:21 AM, Jim Brown wrote:
> Unfortunately the guys who wrote the rules failed to understand the
> physics and the math.
No Jim, you are wrong here. CW is a carrier modulated by a digital
(on/off keyed) signal of a given (baud) rate. That keying will
generate sidebands +/- the baud rate *just like FSK* or even AM which
can be observed on a spectrum analyzer. The ITU formula is quite
accurate in terms of the actual bandwidth for signals with *properly*
*shaped keying*.
Again, the excess bandwidth from improperly shaped keying signals
(clicks) and/or amplifier distortion is something else.
73,
... Joe, W4TV
On 3/30/2016 12:21 AM, Jim Brown wrote:
Unfortunately the guys who wrote the rules failed to understand the
physics and the math. They were WRONG, and it is a misconception under
which we have been laboring for as long as I've been a ham. It was Henry
Ott who woke me up to this when I took his 3-day class on EMC around
2003-4. Henry is a VERY smart guy, one of many who came out of Bell Labs.
73, Jim K9YC
On Tue,3/29/2016 1:28 PM, Joe Subich, W4TV wrote:
>> On 3/29/2016 10:38 AM, Jim Brown wrote:
WRONG! CW speed has NOTHING to do with bandwidth, which is
determined by RISE and FALL times of the keying waveform and
distortion in the RF stages.
The standard word "paris" has 48 elements. That makes the baud rate
for CW (48/60) x WPM or 0.80 x WPM.
ITU defines the "Necessary Bandwidth" for CW as 3 or 5 times the speed
in bits per second (baud rate) where 3 x is for "non fading circuits"
(where the waveform does not need to be so "sharp") and 5 x for "fading
circuits." See:
http://http://life.itu.ch/radioclub/rr/ap01.htm part B.
The same table is found in Title 97, Part 2 of the Code of Federal
Regulations (FCC Rules) as ยง2.202(g)
The constant 'K' sets the minimum bandwidth needed/occupied for the two
recognized cases. Occupied bandwidth in excess of K=5 (or 400 Hz for
100 WPM) would be unacceptable due to improper keying waveforms or
distortion in the RF stages.
73,
... Joe, W4TV
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