1) Can I use the QSK 2500 without using the Key/Paddle input? I have adequate delay in my transceiver.
Reply: If there is adequate delay in your transceiver for the Amp T/R relay, then it is not necessary to go through the 1/4” Key/Paddle IN jack. The QSK 2500 and the amp will be keyed by the signal from the transceiver going into the Amp IN phono jack. Assume that the Amp T/R relay requires 12ms delay and that the transceiver provides 15ms delay, Then it is not necessary to use the 'Paddle/Key IN' jack. Just plug the paddle or key into your transceiver and use it as you would normally. Make sure that the amp key signal from the transceiver is connected to the Amp IN phono jack on the front of the QSK 2500. The QSK 2500 requires 8ms or more delay in the transceiver when NOT using the 10ms delay channel. Most amp T/R relays require much more than 8ms so this is normally not a concern.
2) How do you estimate the ready time of the amplifier T/R relays from their specifications?
Reply: Relays are generally specified by both operate time and bounce time. The amp T/R relay is not ready for RF until the end of bounce time. This time is estimated by adding operate and bounce times. For example, 8ms operate time and 4ms bounce time means the relay is not ready for RF for 12ms.
3) If I use the QSK 2500 delayed Key Out signal and have it set at the factory default value of 10ms delay, does it maintain the full length of each dit and dah?
Reply: Yes. Whatever goes into the Paddle/Key Input appears on the Paddle/Key Output 10ms later. The amplifier & QSK 2500 stay keyed on as long as there is RF on the input connector of the amplifier. No RF signal from the transceiver is lost.
4) I just hooked up the QSK 2500 and it stays keyed on. What is happening?
Reply: The most likely cause of this condition is that the 1/4 in Paddle/Key input plug is a mono plug, not a stereo plug. Since the QSK 2500 can accept either a paddle or key input, it always maintains 2 active channels for the paddle. When using a key, computer, or keyer, a stereo plug is still required. The sleeve connection must be open to avoid keying (i.e. shorting to ground) the unused channel.
Update: The current QSK 2500 accepts a mono plug. The QSK unit checks for the ring being grounded at power on. If the ring is grounded, the ring channel is disabled until power off.
5) Why is my amplifier continually keyed while I am sending with QSK?
Reply: The amplifier T/R relay is not fast or rugged enough to be closed and opened for each dit and dah of a transmission. To overcome this shortcoming, the QSK 2500 keys the amplifier T/R relay at the beginning of each transmission and keeps it keyed for 3 seconds (adjustable from 2 to 10 sec) following the last dit or dah of the transmission. Also, the continual keying eliminates the loud T/R relay hammering noise during the transmission.
5) Why use the QSK 2500 for SSB VOX?
Reply: SSB VOX operation is very similar to QSK operation. Normally, VOX operation involves many short transmissions closely spaced in time. VOX operation of an amplifier can cause annoying T/R relay noise and may reduce T/R relay life. The QSK 2500 greatly reduces the number of amplifier T/R relay operations. It holds the amplifier keyed until there is a 31 second or longer gap in transmissions. SSB VOX receive operation is unaffected. The internal QSK switching connects the receiver to the antenna during receive time independent of the amplifier's keyed or unkeyed state.
6) Why does my K1EL WinKeyer not key the QSK 2500 ?
Reply: The problem is that the keying chip in the WinKeyer does not key the output to ground. This keying chip only reduces the voltage to about +1 volt above ground. The voltage must be reduced below +0.6 volt to key the QSK 2500 (and several transceivers). Replacing the socketed original Toshiba TLP627-2 chip with a Panasonic AQW210EH chip solves the problem. (Thanks to Floyd K8AC for this information.)
Update: I have been told that the new WinKeyers have a keying IC that reduces the amp key voltage below +0.6 volt, eliminating the problem.