[CQ-Contest] CQ-Contest] Impressive demonstration of one dB of signal strength improvement

[wc1m73 at gmail.com]

As you climb the cost curve, the marginal benefit depends a lot on operator skill, who you’re up against, how you and your competition perform during the contest and how many hours you can stay in the chair. An op with mid-level skills will see much more rapidly diminishing returns than an op with exceptional skills. You see this when an elite op visits one of the M/M super-stations and turns in a mind-boggling single-band score.

 

73. Dick WC1M

 

From: John Geiger <af5cc2 at gmail.com> 
Sent: Friday, August 23, 2019 2:58 PM
To: wc1m73 at gmail.com
Cc: Doug Grant <dougk1dg at gmail.com>; CQ Contest <cq-contest at contesting.com>
Subject: Re: [CQ-Contest] CQ-Contest] Impressive demonstration of one dB of signal strength improvement

 

I really enjoyed the powerpoint presentation as well.  In terms of return on investment, what would be the best sized antenna to get, at what height, and which power level linear would be best?  I mean this by getting the most bang for the buck.  I know larger and higher is better for antennas, but there gets to be a point where going to a larger antenna gets really expensive, compared with the improvement it will probably give you.

 

73 John W5TD

 

On Fri, Aug 23, 2019 at 12:55 PM <wc1m73 at gmail.com <mailto:wc1m73 at gmail.com> > wrote:

Terrific presentation, Doug. Wish I'd seen something like this when I got serious about contesting 20 years ago!

A few comments:

- 6% per dB is a lot! That would compensate for my UBN losses in most contests. In the big DX contests with close scores, 1dB or 2dB could make the difference between winning and coming in second or third.

- One of the most compelling slides for me was "Feedline Improvements". I've worked on that in my station over the years, but have never seen a treatment of just how much bang for the buck it can offer.

- I think it's implied in a couple of slides, but ther are also cost/dB equations related to tower height/capacity, namely how much bang for the buck you get by increasing antenna height and/or installing stacks, both of which require taller and/or beefier towers (lots of $$$$, not to mention the cost of longer low-loss feedlines, stack-switching gear, ring rotors, cables, etc.). Yet another item that adds to cost is getting (or fighting for) zoning permission to build more/higher towers. It's tough to quantify these improvements because more effective signal angles don't translate directly to an overall increase in dB.

- There are other improvements that are hard to quantify with a cost/dB formula, particularly improvements on receive. For example, a 4-square on 40 will be many dB below even a modest, low short-forty on transmit, but will have superior F/B that enables better copy of weak stations. Then there's the hard-to-quantify advantage of being able to switch to a vertical array on receive when snowstorm static is wiping out receive on the beam. And with the right transceiver (at more cost) there's the advantage of being able to use antennas with different polarization for diversity reception. That one has definitely boosted my QSO totals on 40. And the cost of improvements like these isn't always in dollars. A 4-quare on 40 is relatively inexpensive to build, but a major amount of work if you install a full-size ground radial system.

- Finally, I'd add one more item to "There is no secret!": Increase your time in the chair. For most of us, more time in the chair translates directly to higher contest scores and there's no dollar cost. While improvement may include getting/staying healthier, eating right, regulating caffeine, getting enough rest before the contest, plotting an off-time strategy, and so on, my own experience is that hours in the chair increase with enthusiasm, grit and determination. Also, I suspect a study might show that the more on-the-air practice you get between major contests, and the more time you spend preparing for a given contest, the more hours you're likely to put in.

73, Dick WC1M

-----Original Message-----
From: Doug Grant <dougk1dg at gmail.com <mailto:dougk1dg at gmail.com> > 
Sent: Thursday, August 22, 2019 1:03 PM
To: cq-contest at contesting.com <mailto:cq-contest at contesting.com> 
Subject: Re: [CQ-Contest] CQ-Contest] Impressive demonstration of one dB of signal strength improvement

On Thu, Aug 22, 2019 at 4:00 PM W3LPL wrote:

These recordings are an impressive demonstration of the benefit of
> one dB of signal strength improvement in a weak signal situation.
> Click on the links on this website:
>
> www.ab7e.com/weak_signal/mdd.html <http://www.ab7e.com/weak_signal/mdd.html> 
>
>
Many years ago, Clarke Greene, K1JX, casually mentioned that he had determined adding 1dB to your signal strength would result in a 6% increase in your contest score (mostly applied to DX contests). I filed that away for future reference.

Test cases are hard to find, but I found one in 2014 when N1UR switched from Low Power to High Power in the CQWW. Same op, same QTH, same antennas, and very comparable propagation near the top of the cycle.

My conclusion: the K1JX "6% per dB" rule was about right.

The exercise for the reader is to figure out how to add dB at the best "dB per dollar" ratio. Not all dB cost the same!

You can find some hints in a presentation I did a while back at CTU:

https://www.contestuniversity.com/wp-content/uploads/2017/06/K1DG_CTU_2015_Ten_Ways_to_Improve_your_Contest_Score.pptx

Slides 5-22 cover this topic.

73,

Doug K1DG

.


_______________________________________________
CQ-Contest mailing list
CQ-Contest at contesting.com <mailto:CQ-Contest at contesting.com> 
http://lists.contesting.com/mailman/listinfo/cq-contest