On Mon, 28 Dec 2009 21:09:46 -0500, DOUGLAS ZWIEBEL wrote: Your post is excellent, and I agree with most of it. I do want to correct an important error. See below.
>If the "noise" is not due to intermod (what Elecraft calls >"desense") Intermod and desense are VERY different things. Intermod is the generation of beat frequencies by a non-linear process (that is, amplitude distortion). Desense (short for desensitization) is the reduction in the gain of a system by such severe rectification of the input signal that the bias point is shifted enough (to either cutoff or saturation) to reduce the gain of the system. Yes, both are the result of overloading of a gain stage (usually the input), intermod simply produces trash and spurious responses, while desense can literally turn the input stage off. As an example, I once owned a very nice little Yaesu talkie that could be biased so strongly into cutoff in downtown Chicago that it couldn't hear a 100W repeater feeding a 9dB gain antenna on a 1,000 ft building two miles away. >then what can cutting back on the >total signal due in terms of making "less noise?" EXACTLY! The vast majority of HF communications circuits are limited by noise that comes in on the antenna, not circuit noise in the receiver. This is definitely true on all ham bands below 20M, no matter where you live, and it's usually true above 20M unless either the bands are dead or you live in a VERY quiet QTH. W8JI has often observed that if the noise in your headphones increases when you connect the antenna, noise in the electronics is NOT a problem. FWIW, I have ALWAYS used pro quality headphones with my ham gear, and certainly don't consider the K3 noisy. Of course, I'm 68, have been a ham for 54 years, and have worked in pro audio for the past 40 years, so my hearing is down a bit on the high end. :) YMMV. It should also be noted that while the K3 comes with multiband graphic RX EQ, there are no bands above 5kHz. That's something that the crew in Aptos might want to add to the "to do" list. 73, Jim K9YC ______________________________________________________________ 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
