http://elecraft.85.s1.nabble.com/150-watt-boots-for-160m-tp4151943p4168117.html
In technical school after being a HAM for over 9 years I learned that it took 10Db change in level to perceive a doubling of audible signal level,,, 3 db hard to detect. I worked on modems during the Vietnam at a site for 1 year after tech school and all our old equipment was lab quality. I did this all day long for 6 days a week for a year. I know and heard what I write.
> From:
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> To:
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> Date: Fri, 11 Dec 2009 14:16:54 -0800
> Subject: Re: [Elecraft] [K3] 150 watt "boots" for 160m
>
> Quite right Bill, in an audio laboratory or perhaps in a very quiet
> telephone circuit.
>
> But radio communications is different according to what I learned in school,
> lo' these many years past. Over half a century ago most radio communications
> engineers began using 3 dB (2:1 power ratio) as the minimum change in a
> signal level that would normally be just discernable to the listener,
> considering typical band noise and QSB. That was based in actual on-the-air
> observations by a great many operators over time.
>
> When considering changing my power level, I never consider it worthwhile to
> change less than 3 dB and more typically 6 to 10 dB as the minimum worth
> bothering with (e.g. shifting from a K2/10 at 10-15 watts CW to a K2/100 was
> a just worthwhile shift).
>
> When I was much younger and more "innocent" I used to scramble for each
> little watt, exulting in running 30 watts instead of 20 watts from a 6L6,
> for example, or tweaking my 6146 rig to run 90 instead of 75 watts and
> feeling sure that made a big difference. It sure seemed to produce more
> results from calls. But, looking back over logs over time, it was clearly an
> illusion..
>
> That's when I acquired the sign that still hangs over my desk to remind me
> that "Believing is Seeing".
>
> So I don't argue with people who want to make what is a quantifiable silly
> choice. Instead I say, "If you want to do it and you believe it's worth it,
> do it."
>
> I'm no different. After all, we humans make most of our choices based on
> emotion and then we use rational logic to justify the choice.
>
> Ron AC7AC
>
> -----Original Message-----
> >From 100 to 150, for 1.7 dB, when Bell Laboratories research (with
> huge capital investment and telephone maintenance dollars on the line)
> determined that 3 dB was the signal strength change discernment for
> most people?
>
> I'm not sure who said 3 dB was the minimum detectable by a listener but I
> believe it's incorrect. 1 dB "roughly matched the smallest attenuation
> detectable to an average listener". (see below)
>
> "The decibel originates from methods used to quantify reductions in audio
> levels in telephone circuits. These losses were originally measured in units
> of Miles of Standard Cable (MSC), where 1 MSC corresponded to the loss of
> power over a 1 mile (approximately 1.6 km) length of standard telephone
> cable at a frequency of 5000 radians per second (795.8 Hz) and roughly
> matched the smallest attenuation detectable to an average listener. Standard
> telephone cable was defined as "a cable having uniformly distributed
> resistances of 88 ohms per loop mile and uniformly distributed shunt
> capacitance of .054 microfarad per mile" (approximately 19 gauge)."
>
>
http://en.wikipedia.org/wiki/Decibel#History>
> 73, Bill
>
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