Frequency min.:
When you command a new frequency via CAT (from WJST-X etc), this is the
lower limit of this band definition.
Frequency center:
The center frequency, which is the frequency of the vertical blue line seen in
the RF sweeps, the test frequency for AF sweeps, and is the frequency used by the Transmitter
Test screen. It doesn't have any other purpose and doesn't have to be the actual center (half way
between min and max).
Frequency max.:
When you command a new frequency via CAT (from WSJT-X etc), this is the
upper limit of this band definition .
Sweep start:
the start frequency for the RF sweep screen.
Sweep step:
the step frequency for each point of the RF sweep plot screen.
BPF number (0-3):
The Band Pass Frequency selection for this band.
LPF number (0-2):
the Low Pass Frequency selection for this band.
Transmit:
Enabled or Disabled, to allow or prevent transmission on this band.
PTT +5V positive:
To enable or enable, for this band, w5V appears on the PTT connector
"ring" connection during transmit. This output is designed to directly interface with the QCX-series
50W Power Amplifier with a simple stereo jack audio cable. Remember, the 50W PA is a SINGLE
BAND amplifier so should only be used on the QDX with a single band, unless you are going to
build an external switched Low Pass Filter. Also remember that the 50W QCX-series amplifier is
designed for CW operation and not suitable for the high duty cycle of digital modes; therefore if
you wish to use this with the QDX transceiver, be sure to limit it to around 20-25W output power;
this will be achieved by using a 12V supply voltage to the 50W PA kit.
PTT grounded:
To enable or disable, for this band, whether the PTT "tip" connection is grounded
during transmit. This PTT output is suitable for driving a typical grounded PTT type amplifier.
Please refer also to the hardware documentation (assembly manual) for more information on the
PTT connection, and the circuits driving it.
The PTT connector is a 3.5mm stereo jack connector. The “ring” connection can be configured as
a +5V PTT output, suitable for switching the QCX-series 50W amplifier. The “ring” connection is
also used on the 50W PA so only a standard stereo audio jack cable is required. The “tip”
connection can be configured as a grounding PTT output for connection to most other amplifiers.
Both the +5V-going and grounded PTT outputs (‘ring” and “tip” connections respectively) are
MOSFET open-drain outputs (utilizing P-channel and N-channel type MOSFETs respectively).
Both outputs have a 470-ohm resistor in series to protect them against accidental damage for
example, shorts to ground.
QDX operating manual; firmware 1_04
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