On 9/27/2013 12:37 PM, Vic K2VCO wrote:
This argument will never die.
As long as some of those doing the talking are ignorant of the facts, yes. :)
I maintain that even ONE dB matters in this situation.
And you are correct. Here are the FACTS. The 6dB and 10 dB "rules of thumb" are based on the FACT that a 6-10 dB change in the loudness of a sound that is well above the background noise level will be perceived by the human ear/brain as "twice as loud," or half as loud. The key words here are "well above the background noise level." This fact is quite well known from the study of psychoacoustics (that is, how humans hear), and is related to the fact that human hearing and sight are logarithmic in their response to loudness and brightness.
The FACTS are very different if the desired "signal" is close to the noise level, or to the level of other sounds. In that situation, a change as little as 1-2 dB can be VERY perceptible, and make the difference between hearing and not hearing it. One of the things I did professionally was mix sound for live jazz performances. It wasn't long before I learned that changes of only 2-2 dB in the balance between instruments was often the difference between just right and not hearing one of them.
Most serious contesters and DXers fight for every dB in their stations. Consider that the gain of the BEST 2-el beam over a dipole at the same height is no more than 3-4 dB, and that adding another element typically adds 1 - 1.5 dB. And that assumes that these are well designed, efficient antennas. Those with traps are 1-3 dB less than that. Note that these are MEASURED numbers, not advertising numbers, and are taken from documentation of an excellent series of tests of a dozen or so tri-banders by N0AX and K7LXC about 15 years ago. Ward and Steve actually measured two big antennas with negative gain as compared to a dipole. :)
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
