++++++++++++++++++++++++++++++ Date: Fri, 18 May 2001 11:07:57 -0500 From: "Timothy A. Raymer" Subject: Re: [Elecraft] K1 Final Adjustments James and Chris, There is an application note on the web page about K1 radios being shipped with incorrect Torroid cores, and how to wind them differently to accommodate the difference in values. Should get your 15 up where it should be. The thing that needs the good turning are the variable capacitors. Tim Raymer 73 de KA0OUV At 12:07 05/17/01 -0700, James A. Doty wrote: >Hi Chris: > >Sounds like my K1 (#644). I get 7watts out on 40 meters and 3watts out on >15 meters. > >The radio works well though. I've got all the goodies installed. Good >sounding rig. > >Chris Cummins wrote: > > > I completed the transmitter tweaking on 40M and achieved 7w out on > a battery just under 13v. However, on 15m 3.5w was as good as I could > do. I thought I remembered reading before that the inductors needed a > good turning or two, so I did that. I was then unable to get anything > out for many hours, I was so frustrated! But, luckily, I got them back > to 3.5w. Is this simply due to the battery voltage or do I need to > re-work the torroids. > >James A. Doty >KI7EL 73 de KA0OUV Timothy A. Raymer +++++++++++++++++++++++++ Date: Sat, 19 May 2001 14:28:42 -0400 From: "Morrow, Michael A." Subject: RE: [Elecraft] K1 Final Adjustments Chris wrote: > I completed the transmitter tweaking on 40M and achieved 7w out on a > battery just under 13v. However, on 15m 3.5w was as good as I could do. > Is this simply due to the battery voltage or do I need to re-work > the torroids. > Chris, I found that initially I also obtained about 3.5 watts maximum output on 15m, with 12.6 volts applied. To get 5 watts out, I had to: (1) Use a 13.8 vdc power supply, and (2) Spread the turns wound on filter board toroid L11 to fill almost all the available space on the toroid, and (3) Compress the turns wound on filter board toroid L12 to fill only about 180 degrees, or half, the available space on the toroid. Your unit may respond differently as far as items (2) and (3) are concerned. The point here is that the low pass filter toroids can be tuned in this manner, after you have peaked the slug-tuned inductors. A *possible* disadvantage of performing items (2) and (3) is that the characteristics of the low pass filter are affected, so it is *possible* that spurious frequency rejection may be affected. Without a spectrum analyzer, it would be hard to tell. 73, Mike / KK5F +++++++++++++++++++++++++++++++++++++++++++++++++