Elecrafters: I built a tuning pulser to use with my K2/100 to tune an external linear amplifier. The pulser is the AG6K design. The pulse is 12 ms on and 24 ms off, and repeats about 28 times per second. This is (by design) much faster than the normal 25 wpm or so keying out of the keyer.
The interface between the pulser and the K2 is a 2N2222 NPN transistor used as a switch. The key line to the K2 is connected to the collector of the transistor (nothing else is connected to the collector), the switching data comes in through the base, and the emitter is grounded both to the ground side of the pulser circuit and the ground side of the keying line back to the K2. I notice what seems to me to be an odd phenomenon when I key the K2 with the pulser. When I first switch on the pulser, the power level in the little LED power meter on the K2 shows the same power level as I get in normal keying. However, after the first instant, the power level indication drops one bar lower (and then stays there as long as the pulser is on) than the power level indication under normal keying. This effect occurs independent of the power level that I set. It happens with the K2's 100 Watt amplifier both in and out. Is this simply an artifact of the metering circuit caused by the peculiar duty cycle of the pulser? Most critically, will it harm the K2? Should I do as one alternative keying scheme shows, and use the transistor to key a reed relay and use the reed relay (which would simply hard short the K2 keying line on key down) to key the K2? TNX & 73, Steve Kercel AA4AK ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
