Check out a 74LS85 4 bit comparator. A single chip with the A=B output going to each of the K3's ACC pin 7, TX INH inputs. 73, Fred KE7X
> -----Original Message----- > From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of > Joe Subich, W4TV > Sent: Sunday, June 01, 2014 9:28 AM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] K3 Receiver Protection > > > > If the serial ports of the K3s are available, > > They tend not to be when doing SO2R - the logger has them tied up. > Of course if the Arduino is capable of handling four 38,400 bps ports > at the same time one can pass the logger data through the device. > > 73, > > ... Joe, W4TV > > > On 2014-06-01 11:19 AM, Doug Person via Elecraft wrote: > > This would be a good place to use an Arduino. If the serial ports of > > the K3s are available, it would only take a small bit of code to > > achieve this. > > > > Doug -- K0DXV > > > > On 05/31/2014 10:46 PM, Don Wilhelm wrote: > >> Jeff, > >> > >> That is a logic question seeking an answer. I don't know of a > simple > >> solution, but it is a matter of selecting a match of the outputs of > 2 > >> band data decoders. If any two are the same, assert TX INH to both > K3s. > >> > >> That function could be implemented with a number of NAND gates or > XOR > >> gates at the outputs of the 2 band decoders. The exact > >> implementation of the logic gates is "left to the student", there > are > >> several possibilities, but it would take a number of external logic > >> gates to implement. > >> > >> If you are really into logical devices, you could program a chip to > >> do that directly from the band data outputs - if all 4 of the > outputs > >> from both K3s are a match, assert TX INH to both transceivers. > >> > >> I do not know of an existing device that will provide that function, > >> so the implementation would have to be created 'from scratch'. Yes, > >> it is possible, it is just a matter of "a few logic gates". > >> > >> 73, > >> Don W3FPR > >> > >> On 6/1/2014 12:04 AM, Jeff via Elecraft wrote: > >>> My station consists of two K-3's, each with a dedicated legal limit > >>> amplifier and SteppIr antenna. To minimize interference between > >>> bands I am using Array Solutions Bandpass filters. However, if both > >>> rigs accidentally wind up on the same band I run the risk of > >>> overloading the front end of the opposite rig and damaging the > >>> receiver (which I've done once...). Does anyone have a way of > taking > >>> the band data information and disabling transmit capability on both > >>> rigs if they are on the same band? How are others using SO2R > >>> avoiding same band transmission and subsequent receiver damage? > >>> Anyone have any experience with the Array Solutions AS-RXFEP front > end protector? > >>> > >> > >> ______________________________________________________________ > >> 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 > >> k0...@aol.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 > > li...@subich.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 fc...@ece.montana.edu ______________________________________________________________ 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
