On Jul 20, 2010, at 9:00 PM, Wes Stewart wrote: > Joe took the words right out of my mouth. > > Personally, I use an "unnecessary" boost regulator when on battery > power or a PS set to at least 14V otherwise. > > [snip] > Unfortunately, this does not apply to transmit IMD. Since the K3 > (like all other solid state transmitters) has a fixed ratio broad- > band transformer between the final FETs and the 50 Ohm output. > > As the voltage falls and current increases, the amplifier impedance > changes (decreases), the final amplifier operates into an increasing > mismatch and the IMD becomes worse. Keeping the voltage to the > final amplifier as high as possible within its specification allows > the lowest possible IMD and highest efficiency. > > 73, > > ... Joe, W4TV >
Interesting. I run a K3 off a couple of pseudo deep cycle 12 volt batteries with an Iota smart charger hooked up. I run mostly digital so IMD is important to me. The Iota runs between 13.1 and 13.6 volts by my K3's meter. Would the difference between that and 14 volts make a meaningful difference in the IMD ? What brand and model booster provides 14 volts? The MFJ promises 13.8. TIA 73 de Eric, KG6MZS ______________________________________________________________ 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
