I am trying to learn the behavior of the K3 ATU Tune. I am switching between two loads. One is dummy load with SWR of about 1.1. The other is a mismatch on an antenna with a measured SWR of about 4.9 (as read off of the LP-100A meter). I am attempting to use the ATU Tune button to bring this unmatched SWR load into a match of 1.5 or under.
So, I am getting strange results. I can use my external AT1KM tuner to bring this into a flat 1:1 SWR. If I press the K3 ATU Tune button I also get the 1:1 SWR reading (or close to it, one bar on the K3 SWR display plut the LP-100A reads 1:1). If I switch the tuner out of service (into a bypass mode where the K3 is looking at a 4.9:1 SWR), I use the K3 to hit XMIT briefly and read out the 4.9 SWR. At this point, it looks like I get a fold back on power of about 50 percent (operating at 10 watts so fold back to 5 watts I guess). The next thing I do is switch the AT1KM tuner back into service without changing anything. When I key down I am getting SWR of 1:1 on the LP-100A and the K3 but the power is still folded back. If I hit the K3 Tune button, it quickly tunes and the power is back to full power (or, 10 watts). So, my question --- If the K3 folds back power due to high SWR then is it required to hit the tune button to reset power when you now have a matched load, 1:1 in this case? I hope I have explained the situation, it is a little involved in set up but I ran across this accidentally while measuring some different antenna loads. Also, I am not sure I am reading the SWR on the K3 correctly. If I hit the tune button for one of my antennas (in this case different from above scenario) and NO EXTERNAL TUNER, The K3 tunes and a single bar shows up on the SWR display which I figure is either 1:1 or close to it. But, I have an LP-100A sitting on the output of my K-line (I have a KPA500 in there but it is not on during these tests) and the LP-100A gives an SWR reading of 1.73:1. Who do I believe? The LP-100A was calibrated at the factory (not a kit). Thanks, 73, phil, K7PEH ______________________________________________________________ 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
