Don: Certainly, for A CW guy like me, sliding a book against the dot paddle would probably work.
However, flipping a toggle switch to get a pulse stream is much more convenient, especially when the electronics attached to the toggle switch cost only a few dollars. (Side note: The tuning pulser is one of the few instances where I have found that home brew is substantially cheaper than getting "store bought.") The idea that the tuning point is affected by the duty cycle is claimed on several different a RF amplifier Web sites. Perhaps they are mistaken. I must admit that I wonder why a genuinely linear system would have its tuning point affected by the duty cycle. Anyway, your suggested fix turned out to be correct. After some searching through my junk collection, I did find a capacitor of the proper value, and increased the pulse duration from 12 to 24 ms while preserving a 33% duty cycle. That completely resolved the "one bar less" effect. I do find that it takes more than 3 dots for the transmitter to come up to full power when I change bands and then run the pulser. The higher the frequency band, the longer the delay, taking only a few dots to come to full power on 80 meters but several seconds to come up to full power on 10 meters. 73, Steve AA4AK Don Wilhelm wrote: > Steve, > > Not to belabor the point, but if simply tuning the amplifier is the > goal, a 50% duty cycle should get the job done. Assuming the amplifier > is supposed to be linear, tuning it at low power should get the settings > close to the correct point and then a very short tuning time would be > needed at full power. As long as the amplifier has a little bit of > reserve (you are not pushing it to its max), a 33% duty cycle should not > be necessary - I just can't understand why the amp's tuning points would > change with the duty cycle. > If you intend to tune the amp for a lengthy time at full rated power, > then yes, it will be stressed at a 50% duty cycle, but for a reasonably > short tuning period, I just don't see the need. > > I would just push a book against the dot paddle and tune away, move the > book when done - no extra steps. > > 73, > Don W3FPR > > ______________________________________________________________ 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
