[TowerTalk] Price of a decibel
wa4dou@juno.com
wa4dou@juno.com
Tue, 2 May 2000 18:41:22 -0400
Hi Jari,
Very interesting but i suspect that for many of us, the prices are
higher.
Some of us elected to bypass scrounging up deals, and just went on and
purchased everything new. Theres something to be said for that too. In
my case, my ground system- 53 rods, 750 ft. of #2 solid copper wire, the
cost of renting a rotary hammer drill several times, the Cadweld charges,
and the cost of renting a "trencher", all exceeded $1000. And that
assigns
no value to my labor. Your analysis is interesting, but i'll bet that
your figures
can be anywhere from accurate to wildly inaccurate. And i'm not so sure
that
the "levels of performance increase" are as distinct or as high in db
change,
and also i doubt that they progress linearly upward, above 70 ft. Many
consider
the 70 ft.(or so) mark, as the point of diminishing returns versus cost,
for 20 meters
and up.
73 Roy WA4DOU
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On Wed, 26 Apr 2000 16:14:16 +0300 jari.jokiniemi@nokia.com writes:
>
>
> Quite many of the comments on this reflector consider if a given
> antenna
> setup is worth the trouble and the money or not. In order to analyze
> this
> rigorously we need some numbers.
>
> Let me begin by defining a few standard setups that show a
> remarkable
> difference in performance, say at the average around 10 dB each step
> in
> practical DX type of operating. Right, I'm not saying that the gains
> of the
> antennas differ much, they are really on the order of only a few dB
> between
> each setup step. The differences come mainly from the antenna
> heights and
> the related takeoff angle improvements. Remember, we are talking
> about DX
> only. You may argue that the differences as seen in practical DX
> operating
> are something else than 10 dB for each step (I have some doubts
> about the
> biggest setup, never tried one.) Ok, let's then just see how you see
> the
> differences and change the formulas accordingly. This is only the
> starting
> point for the analysis.
>
> And the standard setups are:
>
> A - small system - a 40 feet tower and an ordinary trap tribander
> (e.g.
> TH3).
>
> B - medium system - a 85 feet tower and two bigger trap yagis
> including the
> WARC bands
>
> C - big system - a 120 feet tower with 6 el monoband yagis for the
> high
> bands (including the WARCs) and a 3 el monoband yagi for 40. Phased
> wire
> vertical arrays for 80 and 160.
>
> D - a very big system - minimum 3 towers of at least 1 being minimum
> 140
> feet high. Stacked monoband yagis for all bands 40 - 10 m. Ability
> to send
> to at least two directions simultaneously on 10/15/20/40. Phased
> vertical
> arrays for 80 and 160.
>
> Then the prices. Suppose that the property to put up the systems is
> already
> there and is not taken into account in the calculations. Let us only
> consider the towers, basements, guy wires, rotators, cables,
> antennas, and
> building permissions (if required). Let us also allowe one to buy
> something
> new and somethind second hand. The price variations are of course
> quite
> remarkable, but let's anyway try to get some kind of a budgetary
> price.
>
> I'd say that if you budget the following amounts in Finland you will
> quite
> probably get the system mentioned: A = $1000, B = $4000, C = $8000,
> D = ?no
> idea. Your QTH could have much different prices.
>
> And now to the first conclusion. Take the A setup as the baseline.
> The first
> 10 dB enhancement in practical average DX operating costs
> $4000-$1000 =
> $3000, which is $300 per 1 dB. The price of the next dB is then
> $400. As the
> average one would conclude that the price of 1 dB is $350 when
> considering
> antenna systems between setups A to C.
>
> Opinions, more accurate calculations?
>
> -Jari, OH3BU
>
> --
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