Correction ... Paul's call is WD7S (that's what I get for writing e-mail after 10 hours of working on manuals).
73, ... Joe, W4TV > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Joe > Subich, W4TV > Sent: Friday, July 04, 2008 3:26 AM > To: [EMAIL PROTECTED]; 'Lee (WW2DX)' > Cc: 'Elecraft Reflector' > Subject: RE: [Elecraft] K3 Two amplifiers 1 key line > > > > All the work has already been done by Paul, WD7D. See "Improved > Amplifier Interfacing for the Yaesu Mark V FT-1000MP" QST, > September 2004, page 51. The only change necessary to Paul's > circuit is to add a pair of pull-up resistors ... he even has > (had?) circuit boards for the project. > > The circuit will switch PTT and Inhibit lines between HF and > six meter amplifiers based on partial decoding of the Band > data lines. > > Note: partial decoding will not work if you have any transverters > on the K3 and are using the band data outputs for switching them. > > 73, > > ... Joe, W4TV > > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of Don Wilhelm > > Sent: Thursday, July 03, 2008 5:48 PM > > To: Lee (WW2DX) > > Cc: Elecraft Reflector > > Subject: Re: [Elecraft] K3 Two amplifiers 1 key line > > > > > > Lee, > > > > You should be able to provide control lines for HexFETs or > some other > > kind of switch with just a little bit of logic and the > > signals from the > > ACC connector. > > > > Look at the Band Data outputs - the only time *both* Band3 > > and Band1 are > > at a high impedance state is on 6 meters. A NAND gate (with pullup > > resistors on the inputs) will give you a LOW output on 6 > > meters and HIGH > > on all other bands - call this 'partial band decode'. > > Now add an inverter to the KEYOUT-LP signal (another pullup > > resistor is > > needed at its input) and feed its output to one input each > of 2 more > > NAND gates - the 'partial band decode' NAND gate output feeds the > > remaining input of one of these NAND gates and that one will > > have a low > > output when HF is selected *and* Keyout is active. > > Invert the output of the 'partial band decode' and feed the > inverted > > output to the input of the other NAND gate that you connected the > > inverted Keyout signal to - that NAND will have a LOW output when 6 > > meters is selected *and* keyout is active. > > I don't know how much voltage and current your amps PTT > > inputs require, > > so I leave the final keying of the amps up to you. A pair of > > the K2 Amp > > Keying Circuit on the Elecraft website or one of Tom > Hammond's K2 Amp > > Keying kits can be driven by the circuit I described and be > > used to key > > your amplifiers. A 74AC00 dip and a 74AC04 will do this task > > with one > > NAND gate and 4 inverters to spare - it takes longer to describe in > > words than to draw it. > > > > To be safe, I would not consider letting the RF path > > determine which amp > > transmits - if you ever find the ANT1/ANT2 selection changed (by an > > inadvertent button tap), you could send RF to the wrong > amp. You may > > not be able to simply run the KEYOUT to both amplifiers - > > that will only > > work if both amplifiers have the same voltage on their PTT IN lines > > (measure with your DMM with the amplifier on and nothing > connected to > > the PTT IN jack). > > > > 73, > > Don W3FPR > > > > Lee (WW2DX) wrote: > > > I have a HF amp on ANT1 and (soon to be) 6M amp on ANT2. ANT2 is > > > dedicated 6M antenna. > > > > > > Has anyone come up with a way to PTT each amp when on > > desired band? Is > > > it possible to just hook both AMPS to the same PTT key > line so both > > > amps Key at the same time but the RF path would then take over? > > > > > _______________________________________________ > > Elecraft mailing list > > Post to: Elecraft@mailman.qth.net > > You must be a subscriber to post to the list. > > Subscriber Info (Addr. Change, sub, unsub etc.): > > http://mailman.qth.net/mailman/listinfo/elecraft > > > > Help: http://mailman.qth.net/subscribers.htm > > Elecraft web page: http://www.elecraft.com > > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
