QSK 2KW

Description: The QSK-2KW is an external RF T/R interface device that connects to any RF vacuum tube amplifier. It provides full high-speed RF amplifier T/R switching for CW or digital break-in operation. The QSK-2KW requires a low current keying input, allowing it to be directly keyed by a transceiver without the need for a separate external interface buffer device. The QSK-2KW interface utilizes high-speed Gigavac model GH1 and GH3 "5KW" SPDT 12VDC vacuum relays to achieve rapid T/R switching. These relay contacts can easily handle the RF power output of legal limit RF amplifiers. Alternative relays, such as Kilovac HC1 and HC3 vacuum relays, may also be employed. Proper sequencing of the vacuum relays is crucial to ensure that the RF amplifier is not in a conductive state before the RF output and input circuits have switched states. To facilitate this sequencing, the QSK-2KW incorporates a low current JWM Engineering Group four-step port programmable SEQ-QSK T/R Sequencer. The installation of the QSK-2KW necessitates minimal modifications to the RF amplifier for BIAS switching, which is less invasive than completely removing and replacing a slower mechanical TR relay. By using a 1/4 (or 1/8) inch stereo "switched" jack, the RF amplifier can return to its original normal usage when the QSK-2KW is disconnected. This modification requirement is consistent with connecting an Ameritron QSK-5 or Array Solutions QSK-MASTER external QSK T/R switch. The INHIBIT output (RCA) operates at logic low, preventing the transceiver from transmitting RF output until a logic low condition is present. This connection is optional, and users should consult their transceiver owner's manual for additional closed-loop inhibit information. A 12VDC "Amplifier Enable Safety" relay is included to ensure that the RF amplifier does not accidentally enter transmit mode without the vacuum relays being engaged. This relay also supports keying RF amplifiers up to 125VDC. No additional transceiver buffer interface is necessary for RF amplifiers that utilize higher voltage TR relays, such as those from Henry and Alpha (26VDC relays) or Heathkit and Collins (120VDC relays). To install, drill a hole in the rear of the RF amplifier chassis and mount a 1/4 inch (or 1/8 inch) stereo "normally closed switched" jack. The RF amplifier's BIAS line, which is in series with the mechanical TR relay contacts, should be cut open. The two HOT pins of the stereo jack should be wired in series where the BIAS line was severed. The switched stereo jack allows the circuit to close when the plug is removed, restoring the RF amplifier to its original configuration when the QSK-2KW is not connected. No additional modifications to the RF amplifier are required. Users should consult their RF amplifier schematic for wiring information. When the QSK-2KW "Amplifier Enable" switch is activated, the "AMP KEY" of the QSK-2KW goes logic low, energizing the RF amplifier's TR relay. This configuration directs the amplifier's internal RF input coax connector to the input circuit and the RF output coax connector to the output tank circuit. Since the BIAS circuit is open via the QSK-2KW S3 vacuum relay, the amplifier does not enter transmit mode. The receive antenna path is established from the SEQ-QSK S1 to S2 normally closed vacuum relay contacts, then to the transceiver. When a logic low signal is present at "XMIT KEY" from the transceiver, the SEQ-QSK is enabled, initiating the sequencing for the three vacuum relays. The first step involves S1 switching the antenna vacuum relay "RF OUT," connecting the antenna to the RF amplifier output. Next, S2 switches the vacuum relay "RF IN," linking the transceiver output to the RF amplifier input. Finally, S3 activates the BIAS vacuum relay, keying the amplifier. When the logic low signal is removed from "XMIT KEY," the sequence reverses: S3 deactivates the BIAS, S2 disconnects the RF IN, and S1 disconnects the RF OUT. The SEQ-QSK sequence speed can be programmed between 1 to 32 milliseconds, providing flexibility in operation.The QSK-2KW is an external RF T/R interface device which connects to any RF vacuum tube amplifier. It provides full high speed RF amplifier T/R switching for CW or digital break-in operation. The QSK-2KW requires a low current keying input, so it can be directly keyed by your transceiver without requiring a separate external interface buffer devic e. The QSK-2KW interface uses high speed Gigavac model GH1 and GH3 (datasheet) "5KW" SPDT 12VDC vacuum relays to provide lightening fast T/R switching. The relay contacts of the GH serials vacuum relays will easily handle the RF power output of legal limit RF amplifiers.

Kilovac HC1 and HC3 vacuum relays can also be used. Sequencing of the vacuum relays if very important to insure the RF amplifier is not in the conductive state before the RF output and input circuits have switched states. To accomplish sequencing for the vacuum relays, the QSK-2KW uses a low current JWM Engineering Group four step port programmable SEQ-QSK T/R Sequencer.

The QSK-2KW installation does require a minimal modification to the RF amplifier for BIAS switching. This is less invasive then a full removal and replacement of the slower mechanical TR relay. By utilizing a 1/4 (or 1/8) inch stereo "switched" jack, when the QSK-2KW is disconnected from the amplifier, the amplifier is returned to full original normal usage. This RF amplifier modification requirement is the same for connecting an Ameritron QSK-5 or Array Solutions QSK-MASTER external QSK T/R switch.

INHIBIT = Output (RCA) - Logic Low - The transceiver will not put any RF output until logic low appears. This is an optional connection. Consult your transceiver owner`s manual for additional closed loop inhibit information. A 12VDC "Amplifier Enable Safety" relay is added to insure the RF amplifier is not mistakenly enabled into transmit mode without the vacuum relays being enabled.

Adding this relay also supports keying RF amplifiers up to 125VDC. No additional transceiver buffer interface is required for RF amplifiers which use higher voltage TR relays, like Henry and Alpha which use 26VDC relays, or Heathkit and Collins which use 120VDC relays. Drill a hole in the rear of the RF amplifier chassis and mount a 1/4 inch (or 1/8 inch) Stereo "normally closed switched" jack.

Cut open the RF amplifier`s BIAS line which is in series with the mechanical TR relay contacts. Wire the two HOT pins of the stereo jack in series where you opened the BIAS line. The switched stereo jack will allow the circuit to be closed when the plug is removed. This places the RF amplifier back to normal original configuration when the QSK-2KW is not connected. No other modification is required to the RF amplifier. Consult your RF amplifier schematic for wiring information. When the QSK-2KW "Amplifier Enable" switch is turned on (enabled), the "AMP KEY" of the QSK-2KW goes logic low and energizes the RF amplifier`s TR relay.

This places the amplifier`s internal RF input coax connector path to the input circuit and RF output coax connector to the output tank circuit. Since the BIAS circuit is open via the QSK-2KW S3 vacuum relay, the amplifier does not go into transmit mode.

The receive antenna path is from the SEQ-QSK S1 to S2 normally closed vacuum relay contacts, then to the transceiver. When a logic low from the transceiver is present at "XMIT KEY", this enables the SEQ-QSK and sequence begins for the three vacuum relays.

First S1 output switches the antenna vacuum relay "RF OUT" so the antenna is now connected to RF amplifier output, second S2 output switches the vacuum relay "RF IN" so the transceiver out is now connected to RF amplifier input, and third S3 output switches on the BIAS vacuum relay, keying the amplifier. When logic low is removed from "XMIT KEY", the reverse occurs. S3 switches off the BIAS, S2 switches the RF IN, and S1 switches the RF OUT. The SEQ-QSK sequence speed can be programmed in 1 to 32ms