Sounds trivial to me. You must have *some* switch closure or logic signal that activates the PA. Lock out all tuner adjustments when the PA is on.
--- On Sun, 4/18/10, Guy Olinger K2AV <olin...@bellsouth.net> wrote: > From: Guy Olinger K2AV <olin...@bellsouth.net> > Subject: Re: [Elecraft] News from Visalia! > To: "John Fritze" <fritzej...@gmail.com> > Cc: elecraft@mailman.qth.net > Date: Sunday, April 18, 2010, 3:22 PM > On an empathetic note... Can > Elecraft come up a price-appropriate > tuner design that will survive hams at 500 watt RTTY? > > In the midst of trying to concoct a remote home brew tuner > to put > 160-30 meters on a 135 foot end-fed wire, the calculator > and equations > starting telling me that voltages and currents that would > have to be > switched under power could run over 10 kV or 20 amps, > depending on > frequency, at 1.5 kW. > > IF there were a bullet-proof, ham-proof way of insuring > that contacts > were NEVER, EVER switched under power, some things could be > done. But > I can't figure out how to keep ME from doing that when I'm > really > stupid at the end of a contest. > > There is a point at which bulletproof tuner designs seem to > warp into > an entire new expensive component universe. Depending > on the engineer > and personal or commercial risk tolerance, and whether that > might be > RTTY or not, that power level is 200-400 watts. After > that you are > talking Collins Radio kind of commercial/military grade > designs with > motors, vacuum relays and capacitors. Less than that and > one is frying > stuff that is perfectly satisfactory at 200-400 watts. > > The commercial risk is obvious. Burned contacts will > always be blamed > on the manufacturer. If he can't design something that > can't burn, for > a price a customer is willing to pay, what's the point. > > Go out and price a pair of motor driven vacuum variable > capacitors big > enough to cover the variation on 160m and with the voltage > rating to > stand up to tuning antennas at voltage nodes. Gak. > > Sigh. > > Kind of like the sound barrier, not impossible but > definitely a new > mode beyond it. > > The one possible work-around is an Elecraft tuner that will > not work > unless hooked up to an Elecraft amp and a Kx via > proprietary protocol > so it knows whether it is QRO or not and can seamlessly > drop out of > QRO for tuning. Something like how the K2 and the KPA100 > work. > > 73, Guy. > > On Sun, Apr 18, 2010 at 11:06 AM, John Fritze <fritzej...@gmail.com> > wrote: > > I agree, yes please, a remote-able, weatherproofed > 500W tuner (capable > > of 160-6m) would create an instant order here too. I > have relied on > > SGC tuners for many years, mobile, marine mobile and > now at my small > > suburban plot where I have a custom DX engineering 50+ > foot vertical > > with 40 radials. The beauty of SGC tuners is they > only require a 12v > > source. In every situation these tuners have > performed flawlessly in > > harsh environments for years. I was planning on > getting a 500W Tokyo > > Hi Power amp at Dayton this year, but seeing the > Elecraft amp, I will > > wait. The problem is that no one makes a 160-6M > remote weather proof > > tuner capable of 500-600 watts which only needs 12v. > SGC's 500 watt > > tuner doesn't do 160M according to their specs. > What's a space poor > > ham to do? > > > ______________________________________________________________ > > 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 > > > ______________________________________________________________ > 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 > ______________________________________________________________ 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
