>? Good points, Jan E.. Does 0.91 db (1850w vs. 1500w, <1/6 S-unit)
>more output really make a difference on HF when QSB is running around 3
>S-units?. Some folks on AMPS have argued that it does. I am not
>convinced.
>
>I'll naively assume that this is just an academic question -- 1850W PEP
>output exceeds the maximum legal limit permitted to amateur radio operators
>on HF. Of course, none of us should be running more than the legal limit,
>right? It might be politically incorrect to say this on AMPS, but IMHO,
>contest and DX operators who do so are cheating.
? alas, Dick -- to some it does not seem to matter. One contester told
me it was ok to run 3kw out because so and so runs 10kw out. .
> QRO ops who do it for
>ragchewing get no respect from me, either. All of these folks ought to spend
>more time working on better antennas. That's where the FCC gives us a free
>pass to increase ERP on HF.
? In a 75m or 160m group discussion, directional antennas are a distinct
disadvantage.
> It's fun to make amps that can output more than
>1500W, and perhaps that's a good idea so that the tubes can loaf along at
>the legal limit, but we shouldn't be transmitting at higher power levels.
>
>As for .91 db making a difference, theory would suggest that it doesn't.
>Also, I don't think I've ever heard anyone doing on-air tests in which the
>difference between, say, 1150W and 1500W could be detected by the receiving
>station.
? that was what I discovered in my tests.
> However, I will say that my contest run rates and success at
>breaking DX pileups consistently improved when running 1500W on the 87A
>versus 1000W on the SB-221. Quite often I was able to break a pileup by
>switching from the SB-221 to the 87A. That's why I replaced the SB-221 with
>the LK550-ZC. This sort of report may be unscientific and anecdotal, but
>there are many ops who report the same thing. Maybe it's psychological,
>maybe not. When you look at the theoretical gain advantage of stacked beams
>versus single beams, or monobanders versus tribanders, they are actually
>pretty small in terms of both dB and S-units. But there's little doubt about
>which antennas do better in contests.
>
>This reminds me of debates in high-end audio circles. Pyschology and wishful
>thinking have always played big part in that arena. However, there is no
>doubt in my mind that some esoteric equipment combinations actually do sound
>a lot better to a trained ear. The audiophiles swear up and down that it
>sounds different, while the scientifc types say the measurements show no
>difference. Some of the so-called differences are purely psychological
>(there are lots of snake-oil salesmen out there),
? One of the more amusing scam devices is monster-cable company's
smoother-outer flywheel weighted disc to place on CDs. Those who know
how a CD player works realize that this is a joke.
> but some are not. I
>believe this happens because we are lacking complete knowledge about how the
>human ear and brain process sound, and do not have measurement techniques
>that reveal exactly why it sounds better and what it is that the equipment
>is doing differently.
>
>One of the most contentious debates concerns incredibly expensive high-end
>speaker cables and interconnects. After I bought a *very* good system, I
>borrowed a bunch of high-end inteconnects from the local dealer. As I
>recall, some of these cables cost as much as $1000 per pair! I thought this
>was a joke, but I was able to hear distinct differences between different
>brands of cable in their emphasis of high and low frequency signals. It was
>subtle to most people, but I could hear it easily on my ribbon speakers.
? was it $1000 better sounding?
>Subsequent measurements of the cables revealed a 100% correlation between
>what I heard and cable capacitance. Lower capacitance cables emphasized the
>highs, and higher capacitance cables emphasized the lows. Evidently, the
>cables were acting like audio filters. In fact, one set of very expensive
>cables had mysterious sealed black boxes on one end. The capacitance of
>these cables was huge compared to the other cables. They made the highs
>sound mushy and made the bass sound very nice.
>
>I also found, of course, that shorter cables had less capacitance. My system
>uses an active crossover that separates the highs and lows, so I made my own
>set of short interconnects for the highs using some very-low capacitance
>Belden thin coax and some high quality RCA connectors. These interconnects
>cost a fraction of what the high-end cables cost and made the highs sound
>crisper than any of the expensive cables I borrowed. BTW, the same set of
>cables used with different speakers might sound harsh. What you hear depends
>on a complex combination of variables. Psychological aversion to spending
>huge bucks for a two-foot pair of RCA interconnects, or something real?
>
>.91dB may only buy a few S-units, but that can make a huge difference when
>copying weak signals or when the band is noisy. Most people seem to do their
>on-air tests when signals are relatively strong and the differences are
>harder to detect. I think it would be more revealing to do these tests with
>the very weak, almost "ESP" signals that are common in contests and DXing.
>
>The point is, small differences can make a difference, but sometimes that's
>hard to quantify scientifically. There are still some areas where the human
>detector is superior to a hardware detector.
>
? Another factor is that humans are loath to admit that they paid $49
for a CD super flywheel that does nothing except increase bearing wear in
a CD player.
- interesting, Dick.
"There's one born every minute and two to take him." - Phineas Taylor
Barnum
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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