Hey Don, That fixed it, thanks!! I had the wrong value for C52--close, but no cigar. Now to do final assembly, work a few contacts, then build the antenna tuner. Happy, happy!
73, John K6YLG On 9/4/2011 4:19 PM, Don Wilhelm wrote: > John, > > Sorry that I could not help before the Labor Day weekend, but the > Shelby Hamfest called and I just arrived back home. > > While the change on RF voltage on Q4's base between transmit and > receive may appear disconcerting, it may or may not be the problem. > The DDS operates 4913 kHz lower than 14 MHz during receive, or 4913 > kHz higher than the RX frequency when on 40 meters, while during TX, > the DDS frequency is shifted to the TX output frequency. > > It is wise to check and double-check the 14 MHz Low Pass Filter > following the DDS for correct values and good soldering. L4. L5, C50. > C51, and C52. > > 1.2 volts on the source of Q1 is normal. > > Once you have solved the lack of output from the DDS LPF on 20 meters, > you can move on to the PA LPF. Count the turns on L1 and L2 (count > the number of times the wire passes through the center of the core), > and check the capacitors for correct values. > > 73, > Don W3FPR > > On 9/3/2011 12:19 PM, John Donovan wrote: >> I just finished building my KX1 and the receiver works great. I get 2W >> out on 40 but nothing measurable on 20. The odd thing is in receive on >> the base of Q4 I get 2x the signal on 20 that I do on 40; OTOH when I go >> into TUNE mode that signal ramps way up on 40 but remains insignificant >> on 20; by the collector of Q5 it's barely there. I checked the voltages >> on Q1/4/5/6 and they're OK, except that the source of Q1 is only 1.2V. I >> checked solder joints and they all seem fine; ditto inductors, though T1 >> looks to be a tricky bit of work. >> >> Any suggestions would be greatly appreciated. I'd hoped to take this rig >> camping with me this Labor Day weekend, but it doesn't look like that's >> going to happen. >> >> 73, >> John K6YLG >> ______________________________________________________________ >> 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
