The sentence does not fix whether the relay is in the amplifier or in the K3. Perhaps:
"...is transistor output for keying amplifier T-R circuits, ONLY positive voltages up to +200VDC @ 5A." Could a future mod include a blocking diode for negative keying voltages if the circuit will not sink high negative voltages without damage. 73, Guy. ----- Original Message ----- From: "John Lemay" <[email protected]> To: "'Tom Hammond'" <[email protected]>; "'Lee Buller'" <[email protected]>; "'Elecraft Reflector'" <[email protected]> Sent: Friday, February 13, 2009 5:54 AM Subject: Re: [Elecraft] K3 external qro keying line >I can see reason for confusion here - the K3 Manual on page 17 describes >the > "amplifier T-R relay keying output ...." > > Maybe the wording could be clarified. I would certainly form a (incorrect) > picture in my mind of a small power relay, for which + or -ve switching > would be permissible. > > John G4ZTR > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Tom Hammond > Sent: 12 February 2009 17:19 > To: Lee Buller; Elecraft Reflector > Subject: Re: [Elecraft] K3 external qro keying line > > The K3's T-R line output ("KEY OUT") can switch up to 200VDC @ 5A... so it > will > easily switch the +120VDC @ 15-30mA from the SB-220. > > However, it will NOT SWITCH a NEGATIVE T-R line voltage UNDER ANY > CIRCUMSTANCES! > Users with amps which offer a negative T-R line control voltage will have > to > provide alternate switching (relay, or solid state). > > 73, > > Tom N0SS > >>phones, mic, >>line in, and line out > > > At 10:13 02/12/2009, Lee Buller wrote: > > >>HMMMM.... I thought the transistor on the K3 doing the switching is >>pretty tough. I guess we are talking about older amps and not the >>ones that use 12 volts to switch. >> >>I have done the following to.... Radio Shack sells a 5v reed relay >>that is pretty darn fast and has good specs. I just used a dropping >>resistor from a 12 volt line in series with the reed relay and >>worked great for years. I think I used a 180 ohm resistor. Worked >>great. Not QSK, but I don't like QSK anyway. Messes with my head. HI >> >>Lee Buller - K0WA >> >> >> >>In our day and age it seems that Common Sense is in short supply. If >>you don't have any Common Sense - get some Common Sense and use it. >>If you can't find any Common Sense, ask for help from somebody who >>has some Common Sense. Is Common Sense divine? >>______________________________________________________________ >>Elecraft mailing list >>Home: http://mailman.qth.net/mailman/listinfo/elecraft >>Help: http://mailman.qth.net/mmfaq.htm >>Post: mailto:[email protected] >> >>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:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > __________ Information from ESET NOD32 Antivirus, version of virus > signature > database 3849 (20090212) __________ > > The message was checked by ESET NOD32 Antivirus. > > http://www.eset.com > > > > > __________ Information from ESET NOD32 Antivirus, version of virus > signature > database 3850 (20090213) __________ > > The message was checked by ESET NOD32 Antivirus. > > http://www.eset.com > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
