http://elecraft.85.s1.nabble.com/KX3-vs-K3-and-other-rigs-tp6443819p6450810.html
Interesting analysis Dave. Assuming everything is logarithmic, a 33%
However, I think that overstates the advantage of higher power. The
equipment as well. But it does put a useful upper bound on the number.
> To try to put some meaningful numbers on the value of a few extra dB I
> looked at some recent contest scores. Actually not at the scores
> themselves but the number of Q's made. There is of course wide
> variability in this. A lot appears to depend on whether it is
> primarily a NA contest or international. But it might give some clue
> about the value of additional power.
>
> To hopefully remove some of the many variables, I looked only at the
> top few stations. The assumption is that these guys have good stations
> with good antennas in good locations. Have to believe that they put in
> nearly equal effort, i.e. approx the same number of hours. Implicit
> also is the assumption they are approx equally good operators.
>
> In the 2010 ARRL 160m contest these power levels made this many Q's:
>
> 1st 2nd
> QRP 805 718
> LP 1078 1038
> HP 1989 1776
>
> In 2010, with the low sunspot numbers, this was basically a NA
> contest. Not much in the way of DX activity.
>
> Assuming other things are equal - which may or may not be the case -
> it looks like 13 dB (5w to 100w) is worth about a 33% increase in Q's.
> And 25 dB (5w to 1500w) will yield somewhat more than double.
>
> In the 2010 ARRL Sweepstakes:
>
> 1st 2nd
> QRP 982 835
> LP 1257 1244
> HP 1466 1453
>
> This is a NA contest.
>
> Here 13 dB was again about a 33% increase and 25 dB something less
> than double. Indeed having a KW was not much help here.
>
> But if we look at longer distance and check the 2010 ARRL
> International DX contest (looking at stations in NA, not EU or other
> continents):
>
> 1st 2nd
> QRP 1021 912
> LP 2872 2738
> HP 4362 4474
>
> Here 13 dB gives nearly 3x as many contacts. 25 dB gives about 4.5x as
> many.
>
> It looks like a few extra dB may be valuable on longer paths, but not
> worth much within NA, which is about what you would expect.
>
> This does not address the question of what 3 dB is worth. A little
> hard to figure. Within NA 13 dB yields about 33%. So what would 3 dB
> yield? Dunno, but my guess is not much.
>
> How much is 3 dB worth on longer paths? Again hard to say but there is
> probably some threshold, or minimum required, to work the DX. Is that
> threshold 3 dB, i.e. 10w? Honestly probably not. Somewhere between 5w
> and 100w, but unknown.
>
> Maybe some enterprising souls could get together, a few run 5w, a few
> run 10w, a few 25w, and a few 50w. Compare results when it is over.
>
>
> 73 de dave
> ab9ca/4
>
>
>
>
>
> On 6/7/11 7:23 AM, drewko wrote:
> > There is another way of looking at it-- how many additional contacts
> > would potentially be available by utilizing an increase of just 3db?
> >
> > I don't know the answer but there is a somewhat analogous situation in
> > astronomy having to do with the brightness of stars. They are also
> > measured on a logarithmic scale, called magnitude, each magnitude
> > representing twice or half the brightness level of the following or
> > preceding magnitude. A difference of one magnitude does not appear
> > very large to the eye, yet the ability to see one magnitude fainter
> > can yield three times as many stars. I imagine some similar effect
> > might pertain to radio waves.
> >
> > BTW, I'm not asking for more power in the KX3; would be quite content
> > with 10 watts, same as my K3.
> >
> > 73,
> > Drew
> > AF2Z
> >
> >
> > On Mon, 06 Jun 2011 08:56:48 -0700, Alan N1AL wrote:
> >
> >> On Mon, 2011-06-06 at 08:10 -0700, juergen wrote:
> >>
> >>> However from a communications effectiveness point of 20 watts is a
> >>> much more realistic power level, especially for SSB QSO's.
> >>
> >> The difference between 10 and 20 watts is only 3 dB, half an S-unit.
> >> Compared to the 20-30 dB of QSB you often find on the HF bands, you
> >> would hardly even notice such a small difference. I think it is quite
> >> rare that 3 dB would be the difference between making a contact or not.
> >>
> >> Alan N1AL
> >>
> >
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