Hi Mark, In one of the books I have (or had), possibly the Fred Cady KX3 book, there was a diagram of connecting a KX3 along with a K3 to a KPA500/KAT500. The diagram had a splitter in use for the key line, as I recall. And when I had my KX3 that was exactly what I did, and it worked fine. There is no reason, as far as I know, why the two cannot be connected together, provided the key line interrupt device is present if one is using the KPAK3AUX cable.
I looked in my parts bin and found one of those interrupters just a few minutes ago. I disconnected the KPAK3AUX cable and inserted the interrupter at the back of the KPA500, then put the KPAK3AUX cable into it. Now, when I put the KPA500 into Operate mode, the RX level on the KX2 remains unchanged, so there was progress! Keying the KX2 now triggers the amp to do its thing when in Operate mode. I’ve got to go back and dig up my RCA splitter so I can reconnect the Key out line from the K3. If Jack W6FB is monitoring this thread, perhaps he can chime in on the issue of having both radio’s key out lines tied together via a splitter. BTW - I NEVER have both powered on at the same time. 73, Jim / W6JHB > On Apr 28, 2020, at 1:51 PM, Mark Goldberg <marklgoldb...@gmail.com> wrote: > > You should not have the KX2 and K3 connected to the KPA500 PTT in at the same > time. I think you need to disconnect the KPAK3AUX or put in a switch, not a > splitter that keeps them connected at the same time. Your K3 is keeping the > amp in TX. It should only be controlled by the KX2. > > 73, > > Mark > W7MLG > > > On Tue, Apr 28, 2020 at 1:28 PM James Bennett <w6...@me.com > <mailto:w6...@me.com>> wrote: > Hi Mark, > > Yes, I have the KX2ACBL accessory cable in line. That allows me to run the > KX2 Ground and Key Out connections (ring 2) through another cable over to the > KPA500 where it is plugged into the PA Key jack. > > I do not have a key out connection from the K3 to the KPA - I’m using the > “enhanced” band switching with the KPAK3AUX cable. And while I was reading up > on this stuff a few minutes ago I did an experiment. I powered up the K3 then > put the amp into operate mode. The KX2 receive signal level did not drop. So, > it appears that when the K3 is off, it pulls that connection in the KPAK3AUX > cable to ground. I used to have a KX3 a million years ago and I sort of > remember having to run the key out cable from the K3 to a RCA splitter - one > connection to the amp and the other to the KX3, along with a key line inhibit > “thing” between the K3 cable and the amp. Now I just have to find where it > is. Won’t be a happy camper if I can’t find it… > > Thanks for your input - I “think" I’m on the right track. > > 73, Jim / W6JHB > >> On Apr 28, 2020, at 12:57 PM, Mark Goldberg <marklgoldb...@gmail.com >> <mailto:marklgoldb...@gmail.com>> wrote: >> >> Do you have the PTT In on the KPA500 connected to the ACC Out Ring2 as shown >> on page 9 of the KX2 manual? If you use a stereo cable, it will be shorted >> to ground and always have the amp in TX, which would result in what you are >> seeing. >> >> Did you disconnect the K3 key out from the KPA500? The KPA500 senses >> frequency to determine which band, but it still needs the PTT (key out) >> signal to tell it if it should be in TX or RX mode and that key out has to >> come from the radio transmitting. I have my KX3 connected to the KPA500 in >> a simlar fashion and disconnect the key out to tune with a couple watts, >> then connect it to operate. >> >> 73, >> >> Mark >> W7MLG >> >> On Tue, Apr 28, 2020 at 12:02 PM James Bennett via Elecraft >> <elecraft@mailman.qth.net <mailto:elecraft@mailman.qth.net>> wrote: >> I’ve run into an interesting situation that has me puzzled. Probably some >> dumb pilot error, but after an hour or so looking through the manuals and >> thinking about it - I gotta call in the experts. >> >> I’ve had a K3 for ten years and the KPA500/KAT500 for maybe four or five >> years. They work great. I also have a KX2 and thought “why not hook it to >> the KPA500 and give it some punch when I need it?”. Since my antenna >> connects through a coax switch between the K3 and the KX2, the output of the >> KX2 has been flowing through the KPA500/KAT500 since day one, although never >> being amplified. I set the KX2 ATU to bypass and do a “tune” on the KAT500 - >> finds a nice 1:1 match. Keying the KX2 with the amp in standby gives me 10w >> out on the KX2. >> >> Now, with a station tuned in that is say, S8 on the KX2, when I put the amp >> into operate mode, the received signal strength drops about six S-units. >> Going back to standby on the amp restores full receive strength. I have >> pressed the proper band switch on the amp. When I have the amp in operate >> mode and transmit, I get about 190 watts out, with an SWR of 1:1. >> >> By the way - the K3 IS connected to the amp as it normally is, but powered >> off. >> >> So, it seems like the amp is not sensing the RF frequency coming out of the >> KX2 - but why? >> >> Jim / W6JHB >> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> <http://mailman.qth.net/mailman/listinfo/elecraft> >> Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm> >> Post: mailto:Elecraft@mailman.qth.net <mailto:Elecraft@mailman.qth.net> >> >> This list hosted by: http://www.qsl.net <http://www.qsl.net/> >> Please help support this email list: http://www.qsl.net/donate.html >> <http://www.qsl.net/donate.html> >> Message delivered to marklgoldb...@gmail.com <mailto:marklgoldb...@gmail.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
