James; I think you missed Dick's point. The ATU should have a signal that indicates when it needs to do a tune (or is doing one). Simply use that signal to operate a relay. That relay either passes the Keyout signal to the PA (normal), or opens the relay to unkey the PA (tuning). That is exactly what the KAT500 does with the KPA, or any other PA it operates with.
This is a very simple, and elegant automatic solution. 73, Jack, W6FB > On May 30, 2021, at 9:34 AM, James Beitchman <[email protected]> > wrote: > > Thanks, Dick, > > But here is the real issue, not reported in my post. > > My antenna - my only antenna - is a non-resonant 600 foot square loop which > provides amazing performance especially on high bands. It presents SWRs that > are higher than the no-foldback limits of the KPA1500. I believe that limit > is 5:!. So, frankly speaking I was planning on an amp with no built-in ATU > followed by a wide range automatic ATU (ATK) that can handle my SWR (total > cost of amp + ATU well less than KPA1500😊). And I want to do exactly what > you described: have the ATU tune using low K3 power and then switch in the > amp. To do this would require getting RF power from the K3 without > activating the PTT (used to control the amp), then activating the PTT. This > is for remote operation from my home in NYC to my shack/country place upstate > ( K3/0 mini and RemoteRig plus K3 plus internet controlled relay since > 2016),. The problem could be solved with a toggle switch in the shack opening > the PTT line, but not for remote. Thus my question of whether it is possible > to get RF from the K3 w/o activating PTT. > > Thanks again for your attention to this matter. > > 73 > > Buzz > > -----Original Message----- > From: Dick Dievendorff <[email protected] <mailto:[email protected]>> > Sent: Sunday, May 30, 2021 12:08 PM > To: James Beitchman <[email protected] > <mailto:[email protected]>> > Cc: [email protected] <mailto:[email protected]> > Subject: Re: [Elecraft] Can the K3 make power without activating Key Out? > > Buzz: Our KAT500 and KPA1500 antenna tuners interrupt the key line with a > relay for ATU tuning (which is done at exciter power, as we can’t hot switch > ATU relays at QRO and amps don’t deal well with the SWR swings encountered > during ATU tune). The K3, like most exciters, does pull down the KEY PTT line > just before transmitting RF; we just keep that from reaching the amp. This > technique works with a lot of exciters, without a need to modify them to emit > RF without pulling down the KEY line. > > Our KPA1500 ATU tune button interrupts the amp key line, (putting the PA in > standby temporarily) and can be configured to send a message to K3 or K4 to > start tune level RF. When ATU tune is complete, the amp sends a message to > the exciter to cease sending RF, and after RF level drops, the amp restores > the key line interrupt relay. > > 73 de Dick, K6KR > >> On May 30, 2021, at 07:32, James Beitchman <[email protected]> wrote: >> >> I think the answer is no, but I'll ask this question anyway. >> >> >> >> The station configuration is K3 followed by amp followed by automatic >> antenna coupler, where the Key Out line of the K3 is used to switch >> the amp inline. >> >> >> >> I would like to generate RF from the K3 without switching the amp >> inline in order to operate the automatic antenna coupler at low power >> from the K3 before putting the amp inline. This mean generating RF >> from the K3 without activating the Key Out line. Is there any way to do that >> using K3 controls? >> >> >> >> 73, >> >> >> >> Buzz >> >> W3EMD >> >> >> >> >> >> >> >> -- >> This email has been checked for viruses by Avast antivirus software. >> https://www.avast.com/antivirus >> ______________________________________________________________ >> 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] > > > -- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus <https://www.avast.com/antivirus> > > ______________________________________________________________ > 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]
