Steve, I don't think that is unusual. The K3 display reads the voltage after the protective diode, so there you should consider a 0.3 volt drop due to the diode, that leaves 0.4 volts of drop from the power supply to the inside of the connector on the K3. If I assume 17 amps current draw, that says the resistance is 0.023 ohms. You have 10 feet of #12 conductors (yes, one must count the return conductor too) for which the resistance is 0.016 ohms, and add a few extra milliohms for each connector - 2 at the power supply and 2 at the K3, so a 0.4 volt drop across the cable is not unreasonable at 17 amps current draw.
The conclusion is that you can reduce the drop by shortening the power cable - and make certain the connections at the power supply are tight. With some power supplies, the loose connections are on the inside - worthy of a check. 73, Don W3FPR On 11/17/2010 10:02 AM, Steve Ellington wrote: > Can someone take a look at their voltage reading on their K3's DISP-V window > and tell me what they get with key down, full power output into 50 ohms? > My PS shows 13.7v at it's terminals and the K3's display indicates 13.1v. I'm > just wondering if there is excessive voltage drop on the power leads. I'm > using the factory cable. I'm not sure if the K3 is indicating the voltage at > rig's connector or the voltage on the final amp. transistors. > > Steve N4LQ > ______________________________________________________________ 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
