Keying: Audio - microHAM DIGI KEYER Manual

The Keying tab includes controls for the USB Audio processor, PTT and FSK Keyboard.
The sound card configuration depends on the capability of your
application software. Some software can directly drive the sound mixer
controls.
Transmit Level: sets the level of the audio output from the digital to
analog converter. Preset the slider to about 50 to 80% of full
scale and adjust the drive to your transceiver with the TX pot
on the front panel of DIGI KEYER.
RX sub & RX main: these "stacked LED" displays that show the audio
level into the analog to digital controller. Adjust the RX #2
and RX #1 pots on the front panel of DIGI KEYER so that
the strongest signals only occasionally show RED.
Sample Rate: sets the sample rate used to display the RX level
displays. Because of the nature of the Windows sound
system, it is best to set the sample rate to a multiple of the
sample rate (or "clock rate") of your applications. For
example, since MMTTY defaults to a 11025 clock, 44100 Hz
sample rate is the best setting for MMTTY. Similarly since
PSKcore used by many logging programs defaults to 48000
Hz sampling, a 48000 Hz sample rate in router will work best
with PSKcore based programs.
Generate Test Signal: causes DIGI KEYER to output a 1500 Hz audio tone for setting the transmit output
level.
Some tips from Geoff Anderson, G3NPA:
TIP: If you have achieved the correct settings for the transmit levels, you will see that
changing from the PSK tuning tone to typing text, will make the transmitter power swing
from 50% (no typing) to 100% (typing or tuning-tone) as observed on an RMS or average
reading meter. This change in power is correct. If you do NOT see this 50% change (or
greater), then you are probably overdriving the radio. Please note that some radios have
inbuilt power meters which give a PEAK reading and therefore the change in level discussed
above will not be observed.
TIP: Although it is a common belief to the contrary, it is in fact quite alright to let the
transmitter ALC line operate on PSK31. The ALC line will control the drive level without
clipping in the same way that it does on voice operation.
TIP: Don't fall into the trap of thinking that because the transmit signal on the waterfall looks
good that your actual signal is OK. All the waterfall is showing during transmit is the local
audio and NOT the resultant transmitted signal.
microHAM © 2006 All rights reserved
KEYING TAB
USB Audio
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