Pete,
I disagree. While there certainly are no discrete quanta of DX station
layers, there's no question that layers of stations are only workable
when the path loss is less than x.
As an example, look at the peak hours of a high-band EU run from the
east coast in the morning. During the peak hour, stations like HG6N are
20+ over S9 and the 5W/dipole guys are S2-S5. Over the next few hours,
HG6N starts dropping and when they are below S9, the rate is
considerably less. Rates may be about 170-180/hour during the peak
hour, then over the next several hours the rate declines to less than
60/hour. Why? It's not because the band is worked out, as the same
curve happens on Sunday morning (though with somewhat less peak rate as
there are less stations available to work.) It's because the weaker
signals become inaudible in "layers" as the path loss increases. In
between HG6N and DL1XXX/QRP are several "layers" of intermediate
signals, each of which has its own threshold for being workable.
In this case, the variable is propagation-induced path loss, but the
same thing applies with better antennas.
73,
Barry W2UP
Pete Smith wrote:
> The W3AFM series was interesting in its time, but pretty rudimentary by
> today's standard. One of the commonplace things in those days was to equate
> DXing with contesting. This notion of "layers" of stations is insupportable,
> when you think about it - no way 1000 or 2000 QSOs in a contest could be
> sorted into discrete layers by signal strength. I think it is inarguable,
> though, that any increase in either the strength of your signal or your
> ability to hear other stations will increase the number of stations you work
> in a contest period. How large an increase before it makes 1 QSO's
> difference? I have no idea.
>
> 73, Pete N4ZR
>
> At 09:04 AM 8/21/2006, Radiosporting Fan wrote:
>
>> --- Steve London <n2icarrl@gmail.com> wrote:
>>
>>
>>> The original source for the "2 dB improvement" quote
>>> probably comes from QST, September 1966, "Station
>>> Design for DX" by W3AFM:
>>>
>>> "Incidentally, in progressive antenna changes at
>>> W3AFM, increments of only 2 dB in antenna gain have
>>> opened up, in each case, a new layer of
>>> workable central-Asian DX."
>>>
>> Hi Steve,
>> Thanks for digging up this information. I was
>> wondering about the source for this information
>> myself.
>>
>> Given the state-of-the-art in 1966 this sounds
>> reasonable. Given the state-of-the-art in 2006 (and
>> the ability of modern transceivers to dig out weaker
>> signals), I would wonder if the number is closer to
>> 5-dB or more before "another layer" is revealed due
>> simply to technical issues and not operator skill.
>>
>> Anyway...I'm just pondering and not making any
>> statement of fact.
>>
>> Regards,
>> Ev, W2EV
>>
>>
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--
Barry Kutner, W2UP
Newtown, PA
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