Brian; As I noted previously, RF sensing is _always_ active. If the transceiver somehow indicates the wrong band, the KPA will go to the correct one due to its RF sense. As for the band inputs, they are diode protected, with pull-ups on the "inside" of the diodes - that is the side closest to the microcontroller. Floating band inputs (or all 1s) does not cause a band change, so the KPA simply defers to the RF sense.
As you noted, it works quite well. Jack Brindle, W6FB On Jan 5, 2013, at 10:16 AM, Brian Alsop <als...@nc.rr.com> wrote: > Thanks guys. This is how it is behaving. I don't have a schematic for the > KPA-500 so it is impossible to determine if there are pullup resistors or not. > > Glad that Elecraft firmware recognizes that if the band is undefined, RF > sensing of the band become active. > > 73 de Brian/K3KO > > On 1/5/2013 16:02, Don Wilhelm wrote: >> Brian, >> >> OK, Jack Brindle sent me a correction - open BCD lines are at a high >> level, not low, so the band is undefined. Also, the AUXBUS is not in >> use for this situation. >> >> Sorry for the confusion. >> >> 73, >> Don W3FPR >> >> ------------------------------------ >> Brian, >> >> The open BCD lines should signal 60 meters to the KPA500. See the band >> data chart in the K3 manual. >> >> The normal way the KPA500 works (with the K3) when you press a band >> button on the KPA500, it communicates that information to the K3 over >> the AUXBUS - the KPA500 does not receive information from the K3 over >> the AUXBUS, information flows only from the KPA500 to the K3. >> >> Then the KPA500 waits until the K3 switches bands and presents data on >> its BCD outputs - at that time, the KPA500 switches to the same band as >> the K3. >> >> Are you breaking the K3 to KPA500 BCD outputs with your antenna >> switching hardware? Ideally I would think the antenna switching would >> only listen in on the K3 BCD outputs and react accordingly, but you may >> have implemented something more complex. >> >> 73, >> Don W3FPR >> >> On 1/5/2013 8:34 AM, Brian Alsop wrote: >>> Question: What "band" is selected when the Radio=BCD and the inputs >>> are open? >>> >>> It appears to revert to RF sensing. >>> >>> The situation is this. Antenna switching stuff automatically echos >>> the band BCD data to the KPA-500. The exception is if one manually >>> selects an antenna. In that case power to the auto mode PIC is turned >>> off and one gets whatever the PIC outputs are with no supplied Vss. >>> >>> 73 de Brian/K3KO >> >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2012.0.2221 / Virus Database: 2637/5511 - Release Date: 01/05/13 >> >> > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2221 / Virus Database: 2637/5511 - Release Date: 01/05/13 > > ______________________________________________________________ > 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 ______________________________________________________________ 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
