O P E R A T I O N
C H A P T E R 6
If you do not see modulation on the spectrum, please check that the correct input for your
microphone is selected in the
Mixer Form (34)
(see page 128) and that your microphone is
connected correctly (see page 4 for pin-outs of the MIC connector). If you are using any
external audio processing equipment, make sure it is turned on and hooked up correctly. Finally,
if your audio level seems very low, you might try checking
Mic Boost On
on the Setup form –
Audio tab, primary sub-tab (see page 71).
4.
Now that you can see the modulation on the spectrum, it is time to adjust the input. While
transmitting, monitor the values with the
TX Meter
(4)
set to
Mic
. Modify the
MIC Gain (8)
setting until the
TX Meter
shows 0dB on peaks while talking in a normal voice at a normal
distance from the microphone (above 0dB the signal will be compressed).
5.
You are now ready to begin a QSO. If a 50 ohm dummy load was connected, connect an
antenna in its place. Tune to the desired frequency using one of the methods outlined in the
Tuning Methods section above.
Use the
Mode Specific Controls – Phone (8)
including
DX
,
CPDR
,
VOX
and
(Noise) Gate
.
Generally, use either
DX
or
CPDR
to increase average power without adjusting the peaks. Check
Show Transmit Filter on Display
to visualize the band edges of the transmit filter. This filter can be
adjusted on the Transmit Tab of the Setup Form.
Hint:
For information on how to optimize your audio further, please refer to
the
Knowledge Center
(
http://kc.flex-radio.com/search.aspx
) on
our website.
6.
In order to monitor voice transmissions, enable the
MON (15)
button. You may notice a delay
due to buffering in the audio/DSP system. This processing delay is largest when using large
buffer sizes and low sampling rates. If you find this delay objectionable, try decreasing it by
reducing the
Buffer Size
and increasing the
Sample Rate
settings on the Audio tab, Primary
sub-tab
(page 71) and/or DSP tab, Options sub-tab (page 80) of the Setup Form. Make sure
that when changing the Audio Buffer Size, you first
Stop (14)
PowerSDR and make the same
change in the FLEX-3000 Driver (see page 17) before Starting PowerSDR again. See also
Appendix A.
7.
The
Fwd Pwr
setting on the
TX Meter (4)
will read out average power in Watts according to
the Power Amplifier's ADC. While the average has a short time constant, it is still an average
and will not approach 100W in voice modes if calibrated properly even when the
Drive
control
(21)
is set to 100. This is also true when monitoring voice transmissions on an external watt
meter.
Note:
The typical male voice has a peak to average power ratio of 14dB.
Therefore a typical male voice transmission that is peaking at 100W
will only average less than 10W. To raise the average power, use the
DX
(8)
control and the associated slider to increase the compression
in 1dB steps. This must be done carefully and incrementally as adding
too much compression can result in high levels of distortion.
137
2003-2009 FlexRadio Systems