Hi, Jay! The KPA1500 bypasses the power amplifier during ATU TUNE.
Your K3S can communicate its current VFO frequency to the KPA1500 via the ACC cable. The KPA1500 will then change the ATU based on frequency, without transmission. If you have several antennas, as I do, I've done the tuning on each antenna about every 20 kHz across the band in what we've called an ATU "training session". The KPA1500 retains ATU settings for each of these antennas for each "band segment". Then when you QSY to that frequency and transmit, the ATU evaluates SWR, if it's above an SWR threshold (that you set), then the ATU switches the PA to bypass, runs through the available ATU settings, and picks the best one, then restores the PA to full power. Depending on how many antennas you've tuned for, this takes small tens of milliseconds, about 15 msec per ATU setting that needs to be evaluated. This behavior is turned on with a configuration choice, "ATU HiSWR RETUNE". After the training session, I tune across the band and change antennas as I wish, and the pre-tuned ATU settings are determined in a few tens of milliseconds. I don't press any buttons to cause ATU tuning, once I've asked the KPA1500 to memorize the ATU settings for my set of antennas. The KPA1500's amplifier is bypassed when it needs to be for ATU tuning. We can't hot-switch the ATU relays at full amplifier power. ATU tuning is done at exciter power, usually around 20-50 watts, although 100W isn't too much for the relays. If I get to a new frequency that I've never tuned for, I have to press the KPA1500 ATU TUNE button. I have a keying cable connected between the KPA1500 and K3 "straight key" input that allows the KPA1500 to key the K3S when it needs carrier to tune the ATU. We're working on a signal between KPA1500 and K3S on the ACC connector that will hopefully remove the need for that extra keying cable. If this is as clear as mud, send me another note... 73 de Dick, K6KR -----Original Message----- From: [email protected] <[email protected]> On Behalf Of Jason Pecora Sent: Monday, March 26, 2018 14:55 To: [email protected] Subject: [Elecraft] KPA1500 questions... Group good evening. I have a certain style of operation and a question about the KPA1500 I would like to ask in the group. My normal operation is the K3S into a Palstar HF Auto that tunes several antennas on my property. I have had a lot of amplifiers in the past, from solid state to tube amps. Currently I'm running a OMpower 2000+ amplifier. My normal process is that I have 2 memories set on the K-pod, one is that it puts the radio into tune mode at 8 watts out. This 8w output tunes the HF auto with low power until it gets a good match which is very quick. During this 8w tune I have the amplifier in stand-by mode, and all set to tune it next. After the 8w tune, I have the same button set up to "HOLD" the button for a 30w tune in which then I tune the amplifier which is pretty much ready to go off of a list that I compiled, just basically a touch up is all that is needed. The radio stays at 30w after that tune and I'm ready to go... My question is this. Is there an option with the KPA1500 that I don't have to reach over and keep hitting stand-by on the amplifier every time I need to touch up the HF-Auto, can I set up a K-pod button to do this, or a button on the K3S? So basically does the K3S talk to the buttons on the KPA1500 so that I could create a stand-by button on the K-pod...I'm right on the fence on a purchase and this feature would really be of importance to me... Jay KB8O ______________________________________________________________ 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 Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
