The KPA500 is my work, so I’ll try to answer… See discussion below. > On Dec 24, 2014, at 9:22 PM, James Bennett <w6...@me.com> wrote: > > First, let me wish all a very Merry Christmas!
And from the W6FB family as well! > OK, now the problem. I have a KX3 and the full K-line: K3, P3, KPA500, and > KAT500. I have a two position coax switch that I use to drive the amp with > either the K3 or the KX3. When using the K3 (P3 powered off) all works > perfectly. I can change bands by pressing the appropriate band button on the > amp or changing bands on the K3. Doing either results in the amp display > changing to the associated band. When the KPA500 is set for RADIO = K3 and the K3 is on, this is the correct behavior. Pressing a band button sends the button info to the K3 using the Auxbus serial communications. The K3 responds by changing bands, then the KPA responds to the BAND lines change by changing bands itself. Note that the button push on the KPA only causes a command to be sent to the radio, it does not directly cause a band change in the KPA500. The behavior is different for all other RADIO settings. In those cases pushing a band button causes the KPA to change bands. The next thing to realize is that when RF is sensed by the KPA, it will change to the frequency counted band, even if other methods have told it to go to a different band. Of course if the counted band is the same as the previous band change, there will be no further change. Hopefully this is a lot clearer than mud… Also note that powering on or off the P3 has no effect on the KPA500. The K3 must be powered on for the KPA500 integration to work, and must be powered off completely for the KPA500 to mostly ignore it (see BAND discussion below). > But.... If I have the KX3 turned on and the K3 off, pressing a band button on > the amp has no effect. This behaves exactly as described above. The KX3 does not have Auxbus, so it will not receive the button command from the KPA500 and thus nothing will result. > The only way to change bands on the amp is to set the KX3 to the desired band > and then tickle the amp with a little shot of RF. As expected. Note that the K3 better be completely off when this happens, or _it_ will respond to the button press, change bands, and cause the KPA to do something. Also note that the K3 has pull-up resistors on its BAND lines, causing the signals to be pulled to the +5V rail when they are not being driven low. A short time after the K3 is powered off, the +5V rail will drop to 0V. The pull-ups will continue to do their job, pulling the lines to 0, which tells the KPA to change to 60 meters. > Now, the bad news. It does not do this all the time. Not 100% certain, but it > seems to act like this if the amp has been powered off for a few hours. Just > a couple minutes ago I was doing some sleuthing on this issue. After having > the K3 online and sending RF, I tested this out and the amp subsequently > behaved as it should after a K3 shutdown and KX3 startup. The amp changed > bands with its own buttons or via RF from the KX3. Hmmm… Exactly how do you have the K3 and KX3 connected to the KPA500? The K3 loads the BAND lines at all times (and some other AUX signals), even when it is powered off. A change in the BAND lines is required to cause the KPA500 to change bands - if they remain stable then no band change will result. This means that after the K3 powers off and the +5V rail goes to zero, there should be just one band change (when the lines drop). After that any band changes will be due to RF. Do you have some other connection to the BAND lines besides those from the K3? By far, the best way to connect two radios to the KPA500 is to use a switch that disconnects the AUX cable from the K3 before attaching AUX signals to the other radio. Many have noted that you can generally get away with keeping the K3 connected to the KPA500, but results cannot be guaranteed. You might want to change the RADIO settings to something else (try SERIAL) when using the KX3 - with no band change reports coming in the KPA will rely solely on the RF sensing. But, give me a complete description of the setup and I’ll be able to better analyze the situation. Also, what version firmware is in the KPA500? The latest is V1.38, which is very highly recommended. The K3/KPA500 integration code did see several changes in the 1.30 - 1.38 time frame. > Very strange. Anyone (K6KR?) able to shed light on this unusual behavior? Not > a gigantic big deal, but it does make me wonder what's going on. Dick did a great job with the KXPA and KAT500, while the KPA500 is mine. So many developers, so little time... 73! Jack B, W6FB > > 73, Jim > > Jim Bennett / W6JHB > Folsom, CA > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to jackbrin...@me.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
