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

Bob Shohet, KQ2M kq2m at kq2m.com
Fri Aug 23 16:46:18 EDT 2019

This is all relative.  Depends on you, your pocketbook, your qth, your terrain, your neighbors, your town rules and regulations, time of the sunspot cycle and so many other factors.  Not to mention whether or not you buy it new or used.  It also depends on what you are starting out with.  A Rohn 25G  60’ tower requires a massive installation upgrade if you decide that you want to replace your inverted V with a 4 L 40 meter yagi.  But if you already have a separate AB105 tower with heavy duty rotator, mast and acoutrements, then your upgrade cost for additional “bang for the buck” is much lower, especially if you buy it all used.

Are you already at the top of a big hill so that you will be well served by lower and smaller antennas or are you living in a valley with hills all around you and are already in a compromised situation?

Because of terrain and weather factors and/or zoning factors, some qth’s really can’t support certain antenna/tower configurations even if you determine the cost is acceptable.  And how will you service it?  Do you do it yourself or will you need professional assistance?  If so that will greatly impact your calculation of “what would be best”.

It is not a simple question and there are no simple answers.  Each qth and operator will have different decision points and arrive at a different conclusion for what is best for them.


Bob KQ2M

From: John Geiger 
Sent: Friday, August 23, 2019 2:58 PM
To: wc1m73 at gmail.com 
Cc: Doug Grant ; CQ Contest 
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> 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>
> Sent: Thursday, August 22, 2019 1:03 PM
> To: 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
> >
> >
> 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
> .
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