KPA500: Bonehead Input Overload
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Well if it were mine I'd open it up and inspect everything between J3 pin 25 and T1. I would expect to find a well toasted resistor but I don't know the KPA500 well enough to know which one.
I think this is the third report I have seen on this reflector of a KPA500 blown by accidental high power input since I built mine. You have my sympathy but it validates my philosophy of using proactive rather than reactive protection. Please let us know what blew so we can learn from your experience. 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: KPA500: Bonehead Input Overload
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That is a very good argument for having ALC active between the amp and
radio. It would have likely saved the amp. 73 Bob, K4TAX On 5/15/2020 6:12 PM, Andy Durbin wrote: > Well if it were mine I'd open it up and inspect everything between J3 pin 25 and T1. I would expect to find a well toasted resistor but I don't know the KPA500 well enough to know which one. > > I think this is the third report I have seen on this reflector of a KPA500 blown by accidental high power input since I built mine. You have my sympathy but it validates my philosophy of using proactive rather than reactive protection. > > Please let us know what blew so we can learn from your experience. > > 73, > Andy, k3wyc > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: KPA500: Bonehead Input Overload
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In reply to this post by ANDY DURBIN
"That is a very good argument for having ALC active between the amp and radio. "
ALC is just another reactive protection. In my station the KAT500 is commanded to inhibit the KPA500 key line by default. Only when all required conditions are met is the key line enabled. Enabling conditions include Hi_SWR false and TS-590 power set and verified. Set drive power is not allowed to exceed 120% of band max drive power. (That overhead allows the psychological boost of turning the wick up when chasing needed DX but prevents doing anything too stupid.) 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Andy,
Can you expand on this setup please? I would like to emulate it. 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Resources On 5/15/20 4:43 PM, Andy Durbin wrote: > "That is a very good argument for having ALC active between the amp and radio." > > ALC is just another reactive protection. In my station the KAT500 is commanded to inhibit the KPA500 key line by default. Only when all required conditions are met is the key line enabled. Enabling conditions include Hi_SWR false and TS-590 power set and verified. Set drive power is not allowed to exceed 120% of band max drive power. (That overhead allows the psychological boost of turning the wick up when chasing needed DX but prevents doing anything too stupid.) > > 73, > Andy, k3wyc > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: KPA500: Bonehead Input Overload
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In reply to this post by ANDY DURBIN
"Can you expand on this setup please? I would like to emulate it."
It's one of the many functions of an Arduino based station controller. I've been working on a descriptive presentation during the "lock down" and hope to publish the presentation and code before too long. Fair warning though - not many people will think the advantages it offers are worth the complexity. I just developed it for my own satisfaction. Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: KPA500: Bonehead Input Overload
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In reply to this post by ANDY DURBIN
I have a K3S and use PERBAND. While in standby I'm at 100 Watts and in
operate 20 watts kind of fixes the cockpit trouble. If you don't have a K3S or K3 You just have to be extra careful. It works just as well on my other K3S and KPA1500. I have the KPA1500 set up when I change bands it goes into standby mode. The thing is a lot smarter than me. HI.. Ed.. AB4IQ -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Andy Durbin Sent: Friday, May 15, 2020 6:13 PM To: [hidden email] Subject: [Elecraft] KPA500: Bonehead Input Overload Well if it were mine I'd open it up and inspect everything between J3 pin 25 and T1. I would expect to find a well toasted resistor but I don't know the KPA500 well enough to know which one. I think this is the third report I have seen on this reflector of a KPA500 blown by accidental high power input since I built mine. You have my sympathy but it validates my philosophy of using proactive rather than reactive protection. Please let us know what blew so we can learn from your experience. 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by ANDY DURBIN
Hi Andy,
I would be most interested in seeing that once finished... Thanks for sharing... 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Resources On 5/15/20 6:02 PM, Andy Durbin wrote: > "Can you expand on this setup please? I would like to emulate it." > > It's one of the many functions of an Arduino based station controller. I've been working on a descriptive presentation during the "lock down" and hope to publish the presentation and code before too long. Fair warning though - not many people will think the advantages it offers are worth the complexity. I just developed it for my own satisfaction. > > Andy, k3wyc > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: KPA500: Bonehead Input Overload
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In reply to this post by ANDY DURBIN
ALC would not have helped, as it is too slow to respond to a momentary
overload of this magnitude. My station is set up exactly as described by Andy below. Also, the K3 is set to remember output power by band. KAT500 hancles disabling the amp on SWR faults and when tuning (rarely done as Ive taught it my antennas), it will inhibit the KPA500 until the SWR issue is corrected. The KPA500 also communicates with the radio. When it trips or turns off for any reason, it will talk to the K3 and tells it it went offline. It also screams at me to call attention to the issue and the K3 beeps in my headset and flashes a crawl message on its screen to tell me the amp is offline. I have fewer communications between the amp and the tuner with my TS590. On an SWR fault or tuning, the KAT500 keeps the amp in standby until it is happy with the SWR (in my case, below 2:1). Sometimes when changing bands with the '590, it takes a microsecond more to have the KAT500 figure out where the rig QSY'd to, so it keeps the amp offline until it figures things out. In this case, I need to manually re-enable the KPA500 for any reason. Ive also boneheadely transmitted the TS590 at 100w with the amp enabled. The amp IMMEDIATELY goes to standby and screeches loudly at me. Lu W4LT ---------------------- Date: Fri, 15 May 2020 23:43:55 +0000 From: Andy Durbin <[hidden email]> To: "[hidden email]" <[hidden email]> Subject: Re: [Elecraft] KPA500: Bonehead Input Overload Message-ID: <[hidden email]. com> Content-Type: text/plain; charset="iso-8859-1" "That is a very good argument for having ALC active between the amp and radio. " ALC is just another reactive protection. In my station the KAT500 is commanded to inhibit the KPA500 key line by default. Only when all required conditions are met is the key line enabled. Enabling conditions include Hi_SWR false and TS-590 power set and verified. Set drive power is not allowed to exceed 120% of band max drive power. (That overhead allows the psychological boost of turning the wick up when chasing needed DX but prevents doing anything too stupid.) 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: KPA500: Bonehead Input Overload
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In reply to this post by ANDY DURBIN
"My station is set up exactly as described by Andy below."
"Ive also boneheadely transmitted the TS590 at 100w with the amp enabled. The amp IMMEDIATELY goes to standby and screeches loudly at me." A clear indication that your setup is not exactly like mine. My controller won't let me TX at 100 W with the KPA500 in OPER and the key line enabled. I described my protection as follows - "In my station the KAT500 is commanded to inhibit the KPA500 key line by default. Only when all required conditions are met is the key line enabled." I think you will find the KAT500 works exactly opposite to that. It keeps the key line enabled unless it detects a reason to inhibit it. I don't even rely of the KAT500 controlling the key line during Autotune because it re-enables the line too quickly which results in a large power spike. (The power spike is probably short enough that most people wouldn't notice it but it's easily seen on a scope and my LP-100A in peak mode). 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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