Glenn, The most likely reason you did not get a response is that none of us have a good immediate answer.
I suggest that you look at the RF voltages at the collector and base of Q5, Q6 and Q7/Q8 to determine where the problem is located. You can use a 'scope or an RF Probe to check the RF voltage levels (if using an RF probe, do not measure the collectors of Q7/Q8, you may zap the diode). Compare the readings obtained on 80 meters with those obtained on 160 meters. What you are looking for is a stage that has lower gain on 160 meters, so the measurements may be a bit more complex than a simple comparison - the K2 power output control may try to push the RF voltages on 160 higher trying to produce more output - so do the comparisons at a power level that your K2 is capable of delivering on 160 meters (the 2 or 3 watt level should do fine). 73, Don W3FPR > -----Original Message----- > Dear all > > I tried to send this question to the reflector yesterday but I > haven't got any responses so maybe the message did not make it > onto the reflector. One more try... > > I finished building K2 s/n 5361 Tuesday and managed to align it > on all bands 80-10m per the specs in the manual. > First tests (RX only) showed a wonderfully quiet receiver with > "good ears". TX is well within specs, up to 15W power out. > Encouraged by the FB results I started constructing the 160m > extension yesterday. No worries during assembly as far as I could see. > Then, after having installed the 160m PCB into the K2 I started > the alignment procedure.With 2W out all was OK both on 160 and > 80m, no problems peaking output power to about 2,5W. However, > when I try to crank the output power up to 10W as per the > instructions on p9 of the installation manual, I am unable to get > more than 6W output on 160m. 80m is OK (up to 16W output). > I have tried the alternative frequencies for peaking. 2W out is > OK all the time, but I get no more than 6W when I should be > reading 10W out. Cal Cur is set at 3.50A. Checked all solder > joints, toroid winding numbers, what have you. > > _______________________________________________ Elecraft mailing list Post to: [email protected] 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
