Guys,
There is another issue here.
That is :
Just because ones antenna pattern is inferior to an optimum one by 5 or
even 20 db at the best arrival angle, that doesn't mean there is zero
energy at the most important arrival angles. It just means there is less.
QRPers often work the same stations as QRO guys. You see it all the time
in contests. Likewise guys with high radiation angle antennas do work
DX. Maybe just not always the really rare ones, or as many or as quickly.
---------------------------------------------------------------------
It might be more interesting to discuss something like $/db to get to
closer to optimum. Going from low dipole to a higher one might cost
zero to a couple hundred and gain 3 db at about $10-$100/db. Going from
that higher dipole to something directive that picks up 4 db more might
cost a couple kilobucks - $200-500/db. Going from this directive array
to something that picks up another 3 db might cost 5 to 10 kilobucks.
Now you're at > $1000/db. Diminishing returns can happen quickly.
Desktop dB are near the cheapest. One can pickup 10 db (from 100 w) for
about $100-200/db by buying a used amp. Desktop dB can be easier to
keep "in the air" too.
--------------------------------------
So what is that extra db worth to you? Real world constrains besides
money often limit what's possible too.
Paper and electricity is cheaper than hardware. Learn how to use EZNEC
or another antenna modeling program. Spend pennies/per bad new antenna
design rather than big bucks. Go after the cheap dB first. Debunk the
myths about magic or folklore antennas that waste time and money.
Don't forget feedline loss. One example was a local who was trying to
work satellites using 50' of RG58 feedline. Switching him over to
LMR-400 doubled his uplink radiated power and improved reception by even
more.
Read all you can. For example, K9YC's paper referenced in this thread
illustrates how difficult it is to make a vertical work as well as even
reasonable height dipole on the higher frequency bands. The ground
reflection gain of a horizontal antenna (event a zig zag one) is hard to
overcome.
73 de Brian/K3KO
On 7/15/2016 18:02 PM, Jim Brown wrote:
On Fri,7/15/2016 10:07 AM, Wes Stewart wrote:
shows an example where IONCAP says there is no (usable) path between
two stations, yet QSOs are made.
Wes,
There are exceptions to every generalization, even when the
generalization is good most of the time. I recall some well known person
who had come up poor but was no longer saying "I've been poor and I've
been rich, and rich is better." :)
Sure, there are times when a higher angle path is better than a low
angle path (or exists when the low angle path is not present). But
N6BV's statistical data for paths to various locations shows low angle
paths to be better far more often than higher angle paths. It also shows
high angle paths some smaller percentage of the time.
The HUGE problem with using the concept of "takeoff angle," and ONLY the
takeoff angle to describe and evaluate antenna performance is that by
looking at only one curve at a time, it fails to compare one antenna or
mounting height to another. Again, my work looking at the effects of
antenna height in a "flatland" QTH have all plotted the complete
vertical pattern ON THE SAME GRAPH, which clearly shows that for the
range of vertical angles where we can use the ionosphere, higher is
better! N6BV presents this quite well as a "figure of merit" for the
plots of his elevation studies in HFTA, while also showing the complete
vertical data.
73, Jim K9YC
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