DX Connection QSK 2500 Instruction Manual

1) Description
The DX Connection QSK 2500
no amplifier modifications. No amplifier T/R relay interface is required. The QSK unit will interface to
amplifiers whose key jack presents less than 200 volts positive or negative polarity to the QSK unit. The
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QSK 2500 adds a nominal 10ms delay to the transceiver's normal RF delay to eliminate hot switching of
the amplifier's internal T/R changeover relay before the first dit or dah of a transmission. After the first
dit or dah, the amplifier remains keyed up for the remainder of the transmission preventing excessive T/R
relay switching. The QSK 2500
the last dit or dah of a transmission. The QSK unit incorporates hot switching T/R relay protection caused
by some transceivers removing the amplifier key signal before the RF envelop has decayed. The QSK unit
senses for RF on the amplifier RF input connector and only switches from Transmit-to-Receive when the
RF envelop is no longer present. A functional block diagram is included later in this manual.
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The QSK 2500 Key/Paddle input jack accepts a straight key, an external keyer, a bug, a paddle (to use the
transceiver's internal keyer), computer generated CW, or anything that keys the transceiver by grounding
a circuit(s). The input device must sink about 1 ma to ground and accommodate 5 volts open circuit.
These requirements are compatible with the transceiver's Key/Paddle Input jack requirements.
2) Specifications
a) RF Power: 2500 Watts CW/SSB/Data modes
b) Antenna VSWR: < 1.5:1 at 2.5KW, < 2.5:1 at 1.5KW, < 3.0:1 at 1.250KW
c) RF losses: almost lossless relays (much less loss than PIN diodes), silver plated SO-239 connectors
d) QSK internal relays: acoustically quieted and sealed for quiet operation
e) No hot switching of QSK internal relays
f) Provides T/R relay high voltage interface for both new and older amplifiers: The QSK 2500
presents a 5VDC 1ma signal to transceiver Amp key jack. The QSK 2500
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DX Connection
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QSK 2500 Instruction Manual
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allows operating a non-QSK amplifier in QSK mode (or SSB VOX mode) with
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returns the amplifier to standby 2 sec to 10 sec (user settable) following
DxConnection@frontier.com
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input
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output keys (to ground)
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