[TenTec] CW A/B modes

[Alfred Lorona]

There has been much discussion about keying Modes A and B. No one has emphasized that fact that some letters are easier to send using mode A and some letters are easier to send using mode B. That is why both modes are available in some keyers.

If you find that you consistently trip over certain words or certain letter combinations while sending CW, try the other mode.

The differences between the two modes are really quite subtle. It was first identified as a design parameter by famed keyer designed Chet Opal, w9to, in 1975. He called it 'echo' for want of a better name at the time.

All keyers are digital devices and use a dit interval as the basic timing unit. Dashes, interletter intervals and interword intervals are all made up of multiple dit intervals. Modes A and B differ in, for example, what happens when the dash lever is held closed and released during the formation of a dit, the space following the dit or the first part of what would be a dash - usually the first third of a dash interval. In other words, how long must the dash paddle be held closed before release in order to send a dash. Or, saying it another way, how long can the dash lever be held closed without sending a dash. It depends on the timing of the release as determined by the keyer design, if A or B.

The same considerations apply for a dit followed by a dash.

And please, folks, don't call the levers 'iambic'. They are not iambic. They are just paddles. :)

Tnx es 73, AL