That's similar to what I do when operating one K3 remotely. I use a Six Pak driven by a pair of ACC-driven band decoders for antenna switching between the two amps because it's there already, used for SO2R antenna switching when I'm physically at the station. That would be overkill for you - as you say, you just need a SPDT RF relay like the ancient Dow-Key's we used to use for T-R switching in the 60's. You could even buy a Six Pak replacement part open frame relay from WX0B and mount it in a mini-box with some SO-239s, very inexpensive. If I were you, I'd use a simple SPST switch instead of programming the many combinations of DIGOUT1.
I run Key Out from the K3 to the Alpha 87A and key the KPA500 through the ACC cable. If I neglect to put the KPA in STBY when using the Alpha, it keys in parallel but has no drive. No extra relay, no problem. You could also key both amps concurrently with the K3 Key Out line and a Y-splitter. Have fun! /Rick N6XI On Wed, Jan 11, 2017 at 7:39 AM, Jim Miller <j...@jtmiller.com> wrote: > Just a note to document what I am planning for tandem (not simultaneous) > operation of my new acquired ACOM 1500 and my trusty KPA500/KAT500 combo. > I'm strictly single op and no SO2R here so a single feedline to my remote > antenna relay. > > I bought the ACOM 1500 because I felt I needed additional power at times. > It is serving that need nicely. I'm slowly getting more accustomed to the > operation of a manual tune amplifier after a few years of automated > operation of the Electraft line. > > But the KPA/KAT combo is nice for instant-on and quiet idling. I usually > leave my rig on all day if I'm in the house to grab the quick DX spot. At > the first spot of the day of course I need to wait 3 minutes plus tuning > time before getting in the pileup. I find that 3+ minutes torture. The ACOM > 1500 fan is also a bit annoying. > > So I've decided to put the KPA/KAT back in service in the following way. > > Since I have a KANT3a in my K3S I will connect the KPA/KAT to ANT1 and the > ACOM 1500 to ANT2. Selection of the ANT line from the K3S will therefore > exclusively provide RF to one or the other. > > Thanks to the internal preamp of the K3S the DIGOUT1 line is freed up to > provide a signal to switch the single feedline to the antenna farm between > the KPA/KAT and ACOM 1500 outputs. I haven't yet selected a legal limit A/B > relay but there appear to be several available. A separate relay also > driven by DIGOUT1 will switch the KEY line between the amps as well. > > The KPA/KAT will connect via the AUX bus as usual to provide the former > automation including setting KPA per-band power levels. I'll need to put > the KPA in Standby to go "barefoot" and I already have the barefoot level > set to an appropriate value for the ACOM 1500. The normal drive power to > the KPA is also within the range of power I already use to tune the ACOM so > no problems there if I forget to put the KPA in Standby. > > Since DIGOUT1 is per-band and per-antenna the appropriate setting will be > made for each. Of course DIGOUT1 being open collector it will need to be > pulled up and appropriate buffering added to ensure safe operation of the > relay coils. > > So with two button presses I can switch between the two amps and the two > ANT connections eliminates the input switching relay and wiring. > > Of course if a KPA1500/KAT1500 makes a debut all of this will be replaced > in a heartbeat!!! > > Comments or suggestions welcomed! > > 73 > > jim ab3cv > ______________________________________________________________ > 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 rta...@gmail.com > -- Rick Tavan Truckee, 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 arch...@mail-archive.com
