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3) Interconnections
The Control interconnections are shown in Figure 1. The RF interconnections are shown in Figure 2.
Referring to Figure 1, the CW input device (i.e. key, paddle, bug, computer, keyer, etc.) connects to the
¼” Key/Paddle stereo input jack on the QSK unit. For single line input devices such as a key, keyer, bug,
computer CW, etc., a stereo jack must still be used. The center pin is used for CW; the sleeve is left
unconnected. Paddles connect to the center pin and the sleeve in the normal manner (dit center, dah
sleeve).
Note: A stereo plug is no longer required for new QSK units when not using p ddle. The QSK
2500 utom tic lly dis bles the ring ch nnel t power up if it is found to be shorted to ground.
The delayed CW appears at the Xcvr Key/Paddle mini stereo jack on the QSK unit. This jack connects to
the Key or Paddle input on the transceiver.
The transceiver’s Amplifier Key jack connects to the AMP Key IN phono jack on the front of the QSK unit.
The transceiver keys to ground a 5VDC 1ma signal from the QSK unit. (Contact DX Connection to use
Kenwood’s +12 VDC for QSK 2500 keying.) The QSK’s AMP Key OUT phono jack connects to the amplifier’s
AMP Key IN (or ‘antenna relay’, ‘T/R relay’, or ’transmit input’) as shown in Figure 1. It keys the amp T/R
relay to ground. No QSK setting changes are required for keying either positive or negative amp T/R relay
voltage polarity.
A 17 to 25 volt, 200 milliamp, ‘wall wart’ type DC power supply (included with the QSK unit) connects to
the ‘Pwr In’ jack on the front panel. The power supply requires a 2.1 mm power plug (center positive).
See this video for an example. Adding QSK to unmodified Ham Radio Amplifier - YouTube
4) Example Interface to Ameritron AL-811 amplifier series
The QSK 2500© interface to the Ameritron AL 811 series of amplifiers is shown in Figures 5, 6, and 7.
5) Operation
The QSK power switch places the unit in either ‘AMP mode’ or ‘ByPass mode’. In AMP mode, the QSK unit
is active and performs the expected switching of the RF signal.
The QSK unit must be in AMP mode nytime th t the mplifier is to be used reg rdless of the
oper ting mode, i.e. SSB, CW, RTTY, PSK, etc.
If the amplifier is not to be used, then the QSK unit can be set to ByPass mode which turns it’s DC power
off and routes the Key/Paddle input jack to the Xcvr Key/Paddle output jack. See Figure 3. The QSK unit
can be set to AMP mode for transceiver only operation if the amplifier power is turned off or the amplifier
key input is disabled. Some amplifiers can be disabled by a switch on the front panel. For this case, it is
