KPA500 AUX input
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I ask this question in advance of the amp actually arriving, so I can't try
it myself to see if it works. Maybe it's an 'Eric' question anyway. I currently use the AUX output from the K3 to drive my 'Top Ten' type band decoder (actually, it's a W9XT) to drive the antenna selection relays . Having an early K3, the pull-up resistors are in the decoder, not the K3. The question, should anyone venture an educated guess: Can I drive the KPA500's AUX input in parallel with my existing decoder using a Y cord, or should I isolate the K3 from both the KPA500 and W9XT with diodes? Ralph, VE7XF ______________________________________________________________ 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 |
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Running two separate sinks off the same source is always a crap shoot
unless you have analyzed the circuitry of the sinks and the source and specifically determined that they are compatible in all states, which must include all combinations of power on and power off states in all three devices. And you have to be correct in your analysis -- physics is no respecter of persons. There are no rules here other than to actually run them in parallel without isolation is the lucky circumstance. It will be easier to do the isolation to start with than figure out the facts of your particular combo, particularly since the most likely outcome is that you need to do the isolation. 73, Guy. On Sun, Apr 24, 2011 at 8:10 PM, Ralph Parker <[hidden email]> wrote: > I ask this question in advance of the amp actually arriving, so I can't try > it myself to see if it works. Maybe it's an 'Eric' question anyway. > > I currently use the AUX output from the K3 to drive my 'Top Ten' type band > decoder (actually, it's a W9XT) to drive the antenna selection relays . > Having an early K3, the pull-up resistors are in the decoder, not the K3. > > The question, should anyone venture an educated guess: > Can I drive the KPA500's AUX input in parallel with my existing decoder > using a Y cord, or should I isolate the K3 from both the KPA500 and W9XT > with diodes? > > Ralph, VE7XF > > ______________________________________________________________ > 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 > 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 |
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Hi Guy and Ralph
Yesterday, I sent an e-mail to Gary at Elecraft support with that very same question... I am using a Unified Microsystems BCD-10 band decoder which has opto-isolated inputs so it should not be a problem. I don't know W9XT's Top Ten configuration though... Let's see what Gary says – will forward his answer to you. My K3 S/N 586 has the new KIO3 with the pull-up resistors and it works flawlessly with the decoder. 73 Richard - HB9ANM
Richard - HB9ANM
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In reply to this post by Ralph Parker
The KPA500 Band Data inputs do require the pull-up resistor mod on the K3.
However, if your Top Ten decoder has pull-ups to 5VDC, then you should be able to use the Top Ten as your pull-up source as long as the Top Ten is turned on (if the Top Ten is off, then there will be no pull-up and the KPA500 won't respond to the K3 band data input without the K3 pull-up mod). You'll need a true DB15HD splitter cable so as to connect both in parallel. The only reason to diode-isolate the Top Ten is if the Top Ten loads down the band data output from the K3 when the Top Ten is turned off (I don't know if this is the case). Phil - AD5X "... I currently use the AUX output from the K3 to drive my 'Top Ten' type band decoder (actually, it's a W9XT) to drive the antenna selection relays. Having an early K3, the pull-up resistors are in the decoder, not the K3. The question, should anyone venture an educated guess: Can I drive the KPA500's AUX input in parallel with my existing decoder using a Y cord, or should I isolate the K3 from both the KPA500 and W9XT with diodes? Ralph, VE7XF" ______________________________________________________________ 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 |
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In reply to this post by Richard Squire - HB9ANM
I think where you are getting to is dumping the burden of
understanding every possible piece of peripheral gear on Elecraft. (And blaming them if they don't, or give you some errant advice?) It's fine if they want to answer, but in the end, making ANY transceiver, a K3 or a Yaesu 5000, or ..., work with a given PC and a given operating system and drivers and peripheral gear is the OWNER'S problem. Elecraft is responsible for what programs they distribute and drivers for stuff they sell, but after that, it's *US* that have the controls. Personally I want Elecraft spending their time on THEIR stuff. Debugging other manufacturer's software and hardware is on the road that leads to commercial failure. The street sign on that road is "NOBODY WINS LANE". 73, Guy. On Mon, Apr 25, 2011 at 10:05 AM, Richard Squire - HB9ANM <[hidden email]> wrote: > Hi Guy and Ralph > > Yesterday, I sent an e-mail to Gary at Elecraft support with that very same > question... > I am using a Unified Microsystems BCD-10 band decoder which has > opto-isolated inputs so it should not be a problem. I don't know W9XT's Top > Ten configuration though... > Let's see what Gary says – will forward his answer to you. > My K3 S/N 586 has the new KIO3 with the pull-up resistors and it works > flawlessly with the decoder. > > 73 > Richard - HB9ANM > > Guy, K2AV wrote: >> >> >> It will be easier to do the isolation to start with than figure out >> the facts of your particular combo, particularly since the most likely >> outcome is that you need to do the isolation. >> >> 73, Guy. >> >>> The question, should anyone venture an educated guess: >>> Can I drive the KPA500's AUX input in parallel with my existing decoder >>> using a Y cord, or should I isolate the K3 from both the KPA500 and W9XT >>> with diodes? >>> >>> Ralph, VE7XF >>> >>> ______________________________________________________________ >>> 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 >>> >> ______________________________________________________________ >> 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 >> > > > ----- > Richard - HB9ANM > -- > View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-AUX-input-tp6301723p6302881.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > 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 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 |
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In reply to this post by Phil Salas
Phil is essentially correct. It should work just fine.
The KPA500 has protective diodes on its band inputs to eliminate potential problems with external devices supplying power into the KPA's microcontroller when it is powered off. These diodes will also block the KPA's +5V from getting out. I haven't tried it, but I would expect that an unmodified original K3 would work just fine with the KPA in this situation. The required pullups are on the the KPA side, and you indicate that the W9XT device has its own pullups, so the requisite logic states for all devices should be in great shape. One word of caution: if the pullups in the decoder go to any voltage higher than +5V, be sure to add protective schottky diodes in the decoder. This might be a good idea anyway in case you add additional devices. 1N5711 diodes will work just fine. Cathode towards the K3, Anode towards the internal decoder logic. Jack Brindle, W6FB On Apr 25, 2011, at 8:58 AM, Phil & Debbie Salas wrote: > The KPA500 Band Data inputs do require the pull-up resistor mod on > the K3. > However, if your Top Ten decoder has pull-ups to 5VDC, then you > should be > able to use the Top Ten as your pull-up source as long as the Top > Ten is > turned on (if the Top Ten is off, then there will be no pull-up and > the > KPA500 won't respond to the K3 band data input without the K3 pull- > up mod). > You'll need a true DB15HD splitter cable so as to connect both in > parallel. > The only reason to diode-isolate the Top Ten is if the Top Ten loads > down > the band data output from the K3 when the Top Ten is turned off (I > don't > know if this is the case). > > Phil - AD5X > > "... I currently use the AUX output from the K3 to drive my 'Top > Ten' type > band decoder (actually, it's a W9XT) to drive the antenna selection > relays. > Having an early K3, the pull-up resistors are in the decoder, not > the K3. > > The question, should anyone venture an educated guess: Can I drive the > KPA500's AUX input in parallel with my existing decoder using a Y > cord, or > should I isolate the K3 from both the KPA500 and W9XT with diodes? > Ralph, > VE7XF" > > ______________________________________________________________ > 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 ______________________________________________________________ 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 |
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Oops. I need to correct one thing. The +5V from the KPA can be
transferred out. The diodes allow voltage out, but not in. Thus you may see +5V at the band data inputs. If the possibility exists for "accidental powering" of other devices on the bused connection, then appropriate measures should be taken as described in the last paragraph of my email. Usually this is not the case - I doubt the W9XT decoder will see these kinds of problems. Jack Brindle, W6FB On Apr 25, 2011, at 11:06 AM, Jack Brindle wrote: > Phil is essentially correct. It should work just fine. > > The KPA500 has protective diodes on its band inputs to eliminate > potential problems with external devices supplying power into the > KPA's microcontroller when it is powered off. These diodes will also > block the KPA's +5V from getting out. > > I haven't tried it, but I would expect that an unmodified original K3 > would work just fine with the KPA in this situation. The required > pullups are on the the KPA side, and you indicate that the W9XT device > has its own pullups, so the requisite logic states for all devices > should be in great shape. > > One word of caution: if the pullups in the decoder go to any voltage > higher than +5V, be sure to add protective schottky diodes in the > decoder. This might be a good idea anyway in case you add additional > devices. 1N5711 diodes will work just fine. Cathode towards the K3, > Anode towards the internal decoder logic. > > Jack Brindle, W6FB > > > On Apr 25, 2011, at 8:58 AM, Phil & Debbie Salas wrote: > >> The KPA500 Band Data inputs do require the pull-up resistor mod on >> the K3. >> However, if your Top Ten decoder has pull-ups to 5VDC, then you >> should be >> able to use the Top Ten as your pull-up source as long as the Top >> Ten is >> turned on (if the Top Ten is off, then there will be no pull-up and >> the >> KPA500 won't respond to the K3 band data input without the K3 pull- >> up mod). >> You'll need a true DB15HD splitter cable so as to connect both in >> parallel. >> The only reason to diode-isolate the Top Ten is if the Top Ten loads >> down >> the band data output from the K3 when the Top Ten is turned off (I >> don't >> know if this is the case). >> >> Phil - AD5X >> >> "... I currently use the AUX output from the K3 to drive my 'Top >> Ten' type >> band decoder (actually, it's a W9XT) to drive the antenna selection >> relays. >> Having an early K3, the pull-up resistors are in the decoder, not >> the K3. >> >> The question, should anyone venture an educated guess: Can I drive >> the >> KPA500's AUX input in parallel with my existing decoder using a Y >> cord, or >> should I isolate the K3 from both the KPA500 and W9XT with diodes? >> Ralph, >> VE7XF" >> >> ______________________________________________________________ >> 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 > > ______________________________________________________________ > 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 ______________________________________________________________ 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 |
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