[TowerTalk] Raibeam PART-2

Tue, 11 Apr 2000 23:00:02 -0400

Hi Brian,
  You could do well to learn some manners. I've been around for several
cycles
and with modest power i have managed to work many dxpeditions. Also
modest antennas.
All those years(38) i've found the propagation to be there throughout the
cycles. Sunspot
highs and sunspot lows. The real beef you have with what i've advanced as
my opinion
on the situation it that your ego is such that you feel being first in a
pile means something. 
Mine doesn't. If i spend a few minuites in a pileup, it doesn't bother me
at all. I make relatively
few calls, carefully timed, and have never had to wait very long, even
with qrp. But i don't 
bother, if the propagation isn't favorable. I wait till later.
  Furthermore, i have not been critical of contest stations with monoband
yagis,stacks,etc.
If you will go to the propagation forecast in CQ magazine, and read the
parameters that
determine whether your station is in line, below or above the propagation
forecast data, you
will see that "for every change in gain upward or downward of 10 db",
there is a corresponding
change in level of performance, upward or downward. 10 db is big gain,
1-3or 4 db IS NOT! The
entire issue started because someone made nice remarks about his Raibeam.
More power to
him. But 1-2 db is not THE factor that made propagation excellent for
him, it was great conditions,
propagation wise. 
  73 Roy Lincoln WA4DOU (POWER IS NO SUBSTITUTE FOR SKILL, creed of the
QRP'er)
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On Tue, 11 Apr 2000 17:48:37 +0000 alsopb <alsopb@gloryroad.net> writes:
> OM,
> 
> Were you around during the sunspot minimum? Propogation didn't exist
> for the most part.  It was all brute force.  The extra 2,3, or 4 db
> you're willing to throw away made the difference between working 
> VK0IR
> (and many other stations) and not. 
> 
> I am glad you are happy to give up db's.  I urge all for all my
> pile-up competitors doing the same. 
> 
> Please go back to school, read or do something to get your facts
> straight.  It's all in the hard engineering, not in your perceived
> facts.  Yes, you pay to get each db of gain, energy in the right
> direction (azimuthally and altitudinally) and minimize loss.  Yes, 
> you
> have to consider F/B ratio when you contest. (Ask yourself why do
> contest stations have multiple antennas/band, stacks et al and can
> choose which is best at the flick of a switch?)
> 
> Is it worth it?  It depends upon your sense of values.  For what 
> it's
> worth there are quite a few $50K+ stations out there who think it 
> is.
> The want to be first in a pile up not call for hours with a Raibeam
> fed with lossy feedline.
> 
> 73 de Brian/K3KO
> 
> 
> wa4dou@juno.com wrote:
> > 
> > Hi Again,
> >   There are a variety of circumstances where front to back ratio 
> is
> > important. There are also a variety of circumstances where a high 
> F/B
> > ratio will guarantee you miss contacts. An example might be where 
> one is
> > a contester and has only one tower and yagi. A high F/B ratio 
> gives one a
> > sense of great directionality. Yet the antenna that produces that 
> high
> > F/B has only 1-2 db more gain than a smaller yagi or quad. Look at 
> the
> > yagi boom lengths for example. 2 element yagi requires a boom 
> length of
> > .15-.2 wavelengths. 3 element yagi requires a boomlength of .3-.4
> > wavelengths. 4 and 5 element yagis require booms in the 1/2-3/4
> > wavelengths range. Beyond this is generally impractical in the 
> 14-30 mhz.
> > range. Look how the weight and windloading grow as the boom and 
> element
> > count grows. All for 1-3 or 4 db. Look how the cost of the tower 
> and
> > antenna grows ,very disproportionately to the actual and real 
> benefit of
> > the gain.
> >   Example: Compare the gain figures for the Force 12 C3SS, C3, 
> C3E,C3S.
> > Despite the boom length differences of 12 versus 18 ft. and the 
> fact that
> > one antenna is linear loaded on 20 meters while another is full 
> sized,
> > and while the c3E has 3 elements on one band and just 2 on both of 
> the
> > others, these well designed, honestly rated antennas are 
> essentially the
> > same in gain, front to back, etc. Actually the C3SS is probably 
> the
> > better antenna by virtue of the fact that its already rated at 100 
> mph
> > wind rateing while the others are 80 mph. Now go on to compare 
> these gain
> > and front to back ratio figures to the Force 12 C19XR, C31XR and 
> C51XR. I
> > hope i recalled those model numbers accurately. Do you see any 
> real
> > tangeable gain differences? No, because the law of diminishing 
> returns is
> > already at work. Compare the gain and front to back ratios and the 
> boom
> > lengths and the windloading and the weight and the tower 
> requirements and
> > the costs and etc. , and its quite apparent that you'll pay 
> heavily for
> > continuing to hold on to the idea that that great front to back
> > difference and gain difference is worth so much to you. Meanwhile
> > qrp'ers, with many db less sophistication in their stations, will
> > continue working lots of dx, and moving right on up to the honor 
> roll.
> >   Its time for hams to start learning the difference between 
> reality and
> > illusion , fact and sales hype, db's and what they really mean and 
> are
> > worth. When you are talking 2, 3, 4 db, you are not talking about 
> a lot
> > of gain or signal strength difference. The same applies to other 
> brands
> > of antennas and even comparing monoband yagis to multiband 
> antennas.
> >   My tower is built to withstand hurricane force wind, it cost me 
> too
> > much to risk its failure by overloading it with double or triple 
> the
> > windloading for the sake of 1-2 db. Propagation determines whether 
> you
> > have a satisfactory path to dx. Not the extra db.The extra db 
> affords you
> > the luxury of thinking you got something worthwhile for your gain
> > dollars. Yes, i know, races are won in hundredths of a second, but 
> really
> > ,who are you raceing with? I worked Clipperton with qrp on 3 
> bands, and 5
> > with 80 watts. I had excellent propagation. Without that, even 
> 10-20 more
> > db would have been of little value. BTW, my C3SS is fed with 
> Andrews !/2"
> > LDF Hardline.
> >

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