The UM decoders don’t put 12V on the input side. They have optoisolators on the input side that can be driven directly from the K3 without interfering with the KPA/KAT setups. I’ve got several in my setup and they work great. The outputs are active low, so if you have high side driven relays you need their high side driver board also.
Ken K6MR From: Jack Brindle Sent: Sunday, February 25, 2018 14:42 To: Reflector Elecraft Subject: Re: [Elecraft] Advice needed: Remote Station Enhancement Interesting idea, but I would talk to N6TV before going too far down this path. The reason is the introduction of +12V on the Band lines will cause issues in the KPA500 and KAT500. There is a series-connected 220 ohm protection resistor in the K3’s Band signals. When +12V is placed on the band lines, the band voltage no longer is allowed to go below the TTL threshold needed by the KPA and KAT. N6TV has taken a good look at this, and may have a good solution for driving the UM decoder in this setup. There are other decoders that use standard TTL voltage levels that work very well. These include the Elecraft KRC2, the Top-Ten Devices Band Aide decoder, The YCCC MOAS (which may be overkill for this use) and several others that are also very good. 73! Jack, W6FB > On Feb 25, 2018, at 2:09 PM, Dave Hachadorian <k6ll.d...@gmail.com> wrote: > > For a band decoder, I like the Unified Microsystems device: > http://www.unifiedmicro.com/decoder.html > > To use this device, you would put +12 VDC on all the relay coils, and the > decoder would ground the appropriate relay to pull it in. I would use cat 6 > cable for the run out to the relays, with ground/signal on each twisted pair. > > > Dave Hachadorian, K6LL > Yuma, AZ > > > -----Original Message----- > From: Dennis Ashworth > Sent: Sunday, February 25, 2018 2:50 PM > To: elecraft@mailman.qth.net > Subject: [Elecraft] Advice needed: Remote Station Enhancement > > I’ve been remoting my K3, KPA500, KAT500 station via the RemoteRig boxes and > K3/0 mini for two years with solid results. Later this year, I want to make > several enhancements, including the replacement of the KPA500 and KAT500 with > a KPA1500. The amp/tuner should be a fairly straightforward hardware > replacement, but it does necessitate a few station changes which I’m not > certain how to implement. Let me explain and hopefully the masses have > ideas/approaches for consideration. > > 1. I feed a HyTower vertical (optimized for 40M & 80M) on all bands. Where > the driving impedance is close to 50 ohms on 40M & 80 (my bands of interest) > there has been no attempt to match the HyTower on other bands. With the > KAT500, matching was not a problem and I reduced mismatch losses on the feed > line by using hardline from the in-shack tuner to the antenna. > > When I switch to the KPA1500, operation on the unmatched bands might prove > problematic. To address this, I plan to provide switchable matching networks > to transform the HyTower drive impedance on each band to something the > KPA1500 can match. I can design the required impedance transformation > networks, but not sure how to automatically select the various (relay based) > impedance networks required for each band. Clearly, I need to grab band data > from the K3, but what’s the best hardware to use for this task? > > BTW, I want to power the KPA1500 ON with the K3, which requires a Y-cable > modification, or perhaps one of the N6TV boxes? > > 2. I want to interface a K9AY RX antenna 4 position switch to some sort of UI > that I can access remotely. I can design an electrical interface to the K9AY > switch, but controlling and monitoring remotely is the issue. Ideas? > > 3. I have a Windows computer available at each end of the radio circuit. The > only other hardware is a SignalLink used for digital mods. > > 4. Configuring the station for future antenna enhancements (e.g. SteppIR if > we live long enough to see sunspots return!) are great if they come without > significant reliability impacts. > > Any ideas how to accomplish the required switching/monitoring? > > Thanks > Dennis, K7FL > Currently in Panama City, Florida > Station in Battle Ground, WA > > > > > > Sent from my iPad > ______________________________________________________________ > 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 k6ll.d...@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 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 k...@gmx.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
