Dick from Elecraft answered my question. The short answer to my question was “no”.
To answer your question, yes the key line interrupt is set for 3.0:1 as it should be. Mike - K9JRI > On Sep 2, 2018, at 13:01, Barry Baines <[email protected]> wrote: > > Mike: > >> On Sep 2, 2018, at 11:27 AM, Michael Blake via Elecraft >> <[email protected]> wrote: >> >> When the KAT500 is powered on but in the Bypass mode will it still open the >> key line to the KPA500 at the preset level (3.0:1 in my case) if the load >> suddenly goes above 3:1? > > To confirm, is your SWR 3.0:1 or 2.0:1?? > > According to the KAT500 manual (page 21) you can use the KAT500 Utility > Program to set VSWR thresholds for keying an amplifier, “Also, you can set an > SWR threshold at which the key line will not close to enable the external > amplifier to protect it from excessive SWR.” These thresholds can be set for > all bands or individual bands. This would presumably work with bypass mode > as bypass is defined as bypassing the tuning elements in the tuner’s matching > network while the tuner’s SWR meter continues to function and the antenna > selector will still switch to the antenna chosen for a particular band. > > I haven’t made adjustments using the Utility Program so I cannot speak from > personal experience nor do I know what the default values are for VSWR > threshold as I’m not currently where my ham station is to confirm. You will > need to experiment carefully to ensure that you get the intended results. > > Also keep in mind that the KPA500 protects itself. See page 19 of the KPA500 > manual (“Fault Conditions”) which discusses SWR measurements by the KPA500 > itself where “minor faults” in VSWR will result in a 3 dB reduction in output > (“Attenuator Faults”) and continues to operate (if the SWR improves the > attenuator is removed). In the case of severe SWR problems the amplifier > goes into standby (“Hard Faults”). Hard faults require intervention by the > operator to place the amplifier in ‘operate’ presuming that the cause of the > excessive SWR has been resolved. > > The more basic question is what SWR levels the KPA500 will operate. According > to the KPA500 manual (page 17) the amplifier is designed for 1.5:1 or less > (the amplifier SWR LEDs are green). Between 1.5 and 2.1 the LEDs are yellow, > and above 2.1 the LEDs are red. I could not find a reference in the manual > that defines at what SWR level an “attenuator fault” or a “hard fault” due to > high SWR are generated, but this suggests that an attenuator fault presumably > happens when SWR is above 2.1 which is why I’m wondering if there’s a typo in > your first sentence regarding current SWR. > > The KAT500 manual (page 21) also notes, “The Elecraft KPA500 amplifier also > works efficiently into a load SWR of 1.5:1. Suggested values are 1.8:1 to > launch an automatic tuning operation and 1.2:1 for bypass.” > > > Hope this helps, > > Barry Baines, WD4ASW > (Currently in Boston, MA) > >> >> The situation is a remote autotuner connected to a 33’ vertical that I use >> for bands that I do not have a resonant antenna. On those bands the KAT500 >> is in the BYP mode. A remote switch brings all of the antenna choices in on >> a single coax which connected to the KAT500. >> >> 73 - Mike - K9JRI >> >> >> >> >> >> >> >> ______________________________________________________________ >> 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]
