K1EL
WKUSB with WinKeyer3 User Manual
WKUSB
WKUSB User Manual
12/20/2017 Rev 1.0
Page 35
DELAY_TIME = (SWITCHPOINT
×
DIT_TIME)/50
where Switchpoint is a value between 10 and 90.
Dit/Dah Ratio
The ratio between the length of a dit vs. the length of a dah is controlled by this setting. The
agreed upon standard ratio is 1:3 (dit:dah), a dah is three times longer than a dit.
The formula to determine dah/dit ratio is:
DAH/DIT = 3
∗
(nn/50)
A value of 50 selects 1:3, a value of 33 would select 1:2, and a value of 66 would select 1:4. Any
value other than 50 causes distortion of the Morse waveform. Some ops use this option to make
their CW sound less “machine like” but a little goes a long way !
1:2 Dit \Dah Ratio
Normal Ratio
1:4 Dit \Dah Ratio
Three ratio settings for the letter R
PTT Lead and Tail Times
WKUSB’s PTT output is used to control an accessory device in addition to normal CW transmitter
keying. In most cases this device is a linear amplifier but it could be an antenna changeover relay
or PTT input of a transmitter. In all of these cases there are delay requirements that must be met
to insure that the accessory device is switched on before transmission begins and is held on until
transmission completes. This prevents damage to the accessory device due to hot switching.
WKUSB provides three independent PTT delays to meet this requirement.
Lead-in Delay
Tail Delay
PTT
Key
The letter A
PTT Lead-in and Tail Example
The first of these is Lead-In delay which initiates a keying event. When transmit starts, PTT will be asserted
first and then, after the Lead-In delay expires, the key output will be asserted. Lead-In can be set to a value
from 0 to 250 milliseconds in 10 millisecond increments.
Tail Delay specifies the amount of time PTT will be released after Key is released. Like Lead-In delay, it is
adjustable from 0 to 250 milliseconds in 10 millisecond increments.
In setting tail delay there are two considerations, the first is to prevent hot switching and the second is to add
delay to fill in between letters sent by paddle. Most ops don’t want their amplifier to be switched in and out
between letters. An issue arises in that Tail delay is not solely proportional to sending speed. This is
problematic when someone sets a comfortable tail delay at a slow speed and then increases the speed to a
much faster rate. At the faster rate, the tail delay will hold too long after keying stops. Alternatively, if a
comfortable delay is set at a faster WPM rate, PTT will then drop out between letters at a slower speed. To
solve this problem, paddle tail delay is governed by a separate parameter called hang time.
Hang Time is adjustable in four steps and is measured only in wordspace and dit times rather than fixed
milliseconds. This means that the delay will accurately track sending speed. In other words it will decrease
automatically as sending speed increases and vice versa. The four settings for Hang Time are:
