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Operation
(Refer to
Figure 4
for Sequencer Timing Diagram)
Transmit Sequence
1.
Upon keying the
CW IN
or
PTT IN
(low or grounded),
PRE AMP POWER
(receive
systems) is instantly turned off.
2.
T/R AMP
(Linear amplifier) is instantly activated. An external amplifier could take up to
15 ms to fully transfer.
3.
Transceiver
CW
keying or
PTT
OUT closure appears after a programmed delay, activating
the transceiver.
4.
AUX
OUT pulls low after programmed delay.
NOTE:
DX Engineering
ARAV3
or
ARAH2
active receive antenna systems require
approximately 2 ms to mute. Other receive systems may take longer. Program
sufficient delay in the PTT or CW delay to ensure the receive antenna, linear
amplifier or any other switched devices are fully activated or deactivated before
sending PTT closure or CW keying signals to the transceiver.
Receive Sequence
1.
CW
IN from key or
PTT
IN released (high or open on CW or PTT).
2.
PTT
or
CW
OUT to transceiver released (goes high) after programmed delay. This starts
the rest of the RX sequence.
3.
AUX
OUT drops without delay.
4.
T/R AMP
(Linear amplifier) released after the programmed hang time if the transceiver has
released the T/R radio control line.
5.
PRE AMP POWER
OUT is restored after programmable delay.
This sequencing controller automatically adds the PTT or CW input delays to user programmed
hang time delays at all device outputs. Those outputs are the
AUX (aux
iliary), the
PRE AMP
POWER
, and the
T/R
AMP outputs. It accomplishes this by considering the sequencer’s PTT or
CW output ending as the official input signal end point, rather than following the actual
CW
or
PTT
IN openings. This ensures the transceiver input is fully released before external devices begin
to switch back to the receive mode.
Once the keying or PTT input is removed from a transmitter some time passes before RF output
fully decays. This is because CW signals must have a gradual fall time, and because
transmit/receive switching systems in the radio have limited speed. Hang delays set with the internal
switches labeled
PREA (PREA
mp) and
LIN (LIN
ear amplifier) must equal or exceed the longest
possible transmitter RF hang or run-on time.
NOTE:
The
T/R
RADIO input connects to the transceiver’s amplifier control or T/R output line.
This input prevents release on the
T/R
AMP line to the amplifier while the transceiver is
calling for external devices to be in a transmitting mode. The
T/R
RADIO input locks the
PRE-AMP POWER
OUT off when in the transmit position.
