Nick, In your original probelm description, you did not state how much power the K2 display was indicating - and I would tend to believe it indicated that the power was near the requested power value.
Of course, the actual power was not that high, but since the base K2 uses an RF probe type detector to determine the power output level, it only responds to the RF Voltage present, not the actual power. If the effective impedance at the K2 end of the cable was high, the RF voltage would also be high there, resulting in a lower actual power output than the K2 micropressor thinks is present. Bottom line, the RF probe detector can only report the power output properly when the load resistance is known (and athe K2 assumes that is 50 ohms)- in your case, because of the bad coax, the actual load resistance was unknown, and the K2s calculation of output power would be invalid. Hopefully that helps with your understanding of what was happening. I would believe that your cable could have had high resistance connections (likely corroded), but almost anything could have been possible since the electrical characteristics of transmission lines is not straightforward at RF because it depends on the frequency and the electrical length - recall that a shorted transmission line will look like an open circuit at the end opposite the short when it is a quarter wavelength (or multiple) long (and look like a short at the near end at a frequency where it is a half wavelength long), and in between it will appear electrically as an inductor or a capacitor. 73, Don W3FPR > -----Original Message----- > > Doesn't quite qualify for the "stupid mistakes" thread, but another > "stupid question that's not stupid unless you fail to answer it"... > Please educate me... > > I can understand why the power at the DL1 end was low, but why was the > current drawn on the supply at the K2 end so low? If the dodgy old co-ax > had any sort of resistive loss, I'd imagine the K2 would still be trying > just as hard to pump out 5W or 10W, drawing just as much supply juice? > > Is my dodgy cable more shorted, or more open than it should be, or is > this some other effect? > > Thanks in advance, and hopefully you get a chance to scoff at me after I > scoffed at you for pointing out ohm's law as applied to human bodies and > different mains voltages ;-) > > -- > "Nosey" Nick Waterman, G7RZQ, k2 #5209. > #include <stddisclaimer> [EMAIL PROTECTED] > It is ten o'clock; do you know where your processes are? > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
