[CW] CW Speed Limit ???

[N2EY at aol.com]

In a message dated 3/7/2005 10:32:28 AM Eastern Standard Time, "K0HB" <k-zero-hb at earthlink.net> writes:

>> From what I get, there is a speed limit 
>> imposed on an operator that is far
>> below a speed that many hams currently use.
>> That of course is allowing for
>> fading/QSB which we all know rather too well.
>
>The so-called "bandwidth proposal" seeks to >regulate the bandwidth of the
>transmitted signal. The bandwidth of a >transmitted signal "is what it is",
>is unrelated to conditions at the receiver, and >the value of K is immaterial
>at the transmitter.
>

Suppose a transmitter has the recommended 5 ms rise and fall times. Such a rig, when keyed, will have a transmitted bandwidth of ~150 Hz, regardless of how fast the Morse is sent. 5 wpm or 50 wpm, the transmitted BW is 150 Hz.

At 60 wpm, the theoretical on time of a dit is 20 ms. The rig described will spend 5 ms on rise, 10 ms "on" and 5 ms falling for a 60 wpm dit. Whether that is considered "hard" or "soft", and whether it can be copied in fading or nonfading conditions is a question for the receiving operator.

At 120 wpm, the theoretical on time of a dit is 10 ms. The rig described will spend 5 ms on rise and 5 ms falling for a 120 wpm dit, and only an instant fully "on". 

So the 5 ms rise/fall times do place a speed limit of sorts. But whether it is really a problem depends on the receive operator. 

73 de Jim, N2EY