I would postulate that the worth of a dB is not linear, but rather, there
is a tipping point. If Tim was using a beam at 50-70 feet on the high
bands, I think his results would be more in line with those of N1UR. With
a doublet, the first 6dB got him into barefoot & beam range, and over
general QRM levels.
BTW, Tim, congratulations for the AMAZING scores with that setup.
73, Dave K3ZJ
On Tue, Mar 1, 2016 at 9:41 AM, Tim Shoppa <tshoppa@gmail.com> wrote:
> Certainly, Tom! My antenna is a 130-foot doublet, up 75 feet between trees,
> fed by tuners and ladder line.
>
> On 160M the antenna is fed by tying the ladder line together at ground
> level and feeding it against ground as a "Marconi T". Essentially the
> ladder line becomes a vertical element and the 130-foot top becomes a
> tophat.
>
> Some pictures of ladder line relay switching and tuners here:
> http://www.trailing-edge.com/tuners.html
>
> I have a couple 160M receive antennas too (a K9AY for NE/SW, and a
> west-facing pennant.)
>
> Tim N3QE
>
> On Tue, Mar 1, 2016 at 9:29 AM, Tom Carrubba KA2D <ka2d@arrl.net> wrote:
>
> > Hi Tim
> >
> > May I ask, what antenna do you use?
> >
> > Thanks
> > Tom KA2D
> >
> > -----Original Message----- From: Tim Shoppa Sent: Tuesday, March 01, 2016
> > 6:40 AM To: cq-contest@contesting.com Subject: Re: [CQ-Contest] How much
> > is a dB worth ?
> > My interpolation on CW and RTTY using my personal logs, for 24-34 hour
> > efforts in 48 hour contests and almost unchanged antenna system, after
> > adding two different amps.
> >
> > Note that my numbers only track transmit power dB, not receive system
> dB's.
> > I have improved my receive system on 160M but not on the other bands in
> > this time.
> >
> > Note that for CW tests I was often in the top 10 box for assisted LP but
> > now am not necessarily in the top 10 box for CW now that I enter assisted
> > HP. And I actually lump a couple different contests together and apply
> some
> > tweaks based on what I feel to be changes in propagation to keep things
> > comparable to my last year on LP.
> >
> > Going from barefoot to AL-811H (8dB) doubled my QSO's and tripled my
> > scores. With this change I usually get S&P on first call and can often
> hold
> > a run frequency for a good time in the biggest CW and RTTY contests.
> >
> > Going from AL-811H to AL-1500 (another 4dB) added another 30% to my QSO
> > numbers and another 50% to my scores. With this change I almost always
> get
> > S&P on first call and only rarely get pushed off a run frequency.
> >
> > So making a little table, just using ARRL DX CW as an example:
> >
> > 100W = 1000Q's
> > 600W = 2000Q's (8dB more power for 3dB more Q's).
> > 1500W = 2400Q's (12dB more power for 3.8dB more Q's)
> >
> > 100W = 1M points
> > 600W = 2.7M points (8dB more power for 4.2dB more points).
> > 1500W = 3.5M points (12dB more power for 5.5dB more points).
> >
> > I would say each dB more power, means 7 to 9% more Q's.
> > And each dB more power, means more points 11 to 12% more points.
> >
> > There is some "compression" to the score expansion (a dB is worth more
> > moving from 100W to 600W, than a dB moving from 600W to 1500W).
> >
> > I think this compression factor would have been less, or not there at
> all,
> > if I had improved my receive system as well as my transmit power (i.e. I
> am
> > now an alligator, all mouth, no ears).
> >
> > If I had chosen WPX, the QSO ratios would be similar, but the point
> ratios
> > will be a little larger (WPX mults continue to grow quicker than ARRL DX
> or
> > CQ WW mults.)
> >
> > Tim N3QE
>
>
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