The circuit is called an OR gate - output high if either input is high. The easiest way to homebrew one is to use a dual opto-isolator with the outputs in series ...
The attached assumes DIGOUT will sink a few mA - adjust R for the current required by the opto-isolator you use. 73, ... Joe, W4TV > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Julian, G4ILO > Sent: Sunday, July 12, 2009 1:19 PM > To: [email protected] > Subject: [Elecraft] KEYOUT PTT only when transverter band selected > > > > I don't have a linear amplifier. I do have a transverter, and > I use the KEY OUT jack to put it into TX. Trouble is, it puts > the transverter into TX whatever band I'm using. For LO > stability reasons (not to mention that I can never remember > to switch the transverter off when I'm not using it) I'd > prefer to be able to leave the transverter switched on but > only receive a PTT signal when the VHF band is selected. I > think that means I'd need a circuit that combines the state > of DIGOUT0 with KEYOUT-LP, such that it grounds the > transverter PTT input when DIGOUT0 is 0V and KEYOUT-LP is > grounded. Has anyone made something like that? > > ----- > Julian, G4ILO. K2 #392 K3 #222. > * G4ILO's Shack - http://www.g4ilo.com > * KComm - http://www.g4ilo.com/kcomm.html > * KTune - http://www.g4ilo.com/ktune.html > > -- > View this message in context: > http://n2.nabble.com/KEYOUT-PTT-only-when-transverter-band-sel ected-tp3246434p3246434.html Sent from the Elecraft mailing list archive at Nabble.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
