I'm glad you found something useful in the actual experience stories.
..."I see some of the self declared techie types are concerned about my
motives for asking the question in the first place. So be it."...
That would be me. I could not imagine anything that experience could
show that modeling could not on simple antennas like these.
..."When you are talking a gain of 2 or less DB and modeled front/back
to side nulls of about the same value, actual experience helps."...
I would think it would be very difficult to actually measure this small
difference given all the variations of each installation.
...."If the antennas I was considering had modeled gains and F/B ratios
from 4-6, and 15-20 DB, either antenna would probably be worth a try."....
Neither of these antennas have any F/B. They are bi-directional.
..."At modeled values in the 2 or less DB range, I was simply trying to
find out if actual experience justified the effort of a loop over a
dipole."...
Modeling should show zero F/B, unless it is influenced by other objects
in the vicinity (which also have to be included in the model). If
actual measurements show a non-zero F/B then the results are probably
also affected by other objects, or simply measurement errors.
If you model these antennas you can go thru a lot of configurations in a
lot less time than it takes to build one and try to evaluate it. You
will see that performance changes with the shape of the loop, with
orientation (if it is not circular), with feedpoint location, and with
height above ground. The effect of some of these is minor, but some
variations have a major effect on performance. You can also optimize
all these parameters to produce a loop best suited for your purposes.
You can't do that by obtaining testimonials, with the exception that
experimental data should be able to notice some change due variation of
the major contributors (like feedpoint location and height above ground).
Jerry, K4SAV
fraz1 wrote:
>I see some of the self declared techie types are concerned about my motives
>for asking the question in the first place. So be it. I suggest that many of
>the answers posted are of benefit to others reading the "reflector".
>
>Yes, I am aware of physics and science, and ( geesh) even have experience in
>modeling antennas. When you are talking a gain of 2 or less DB and modeled
>front/back to side nulls of about the same value, actual experience helps. If
>the antennas I was considering had modeled gains and F/B ratios from 4-6, and
>15-20 DB, either antenna would probably be worth a try. At modeled values in
>the 2 or less DB range, I was simply trying to find out if actual experience
>justified the effort of a loop over a dipole.
>
> I received input from guys using both antennas for short haul rag chewing and
> from guys using it for DX only, and some for both. They usually tell how it
> is configured. I find it all useful information. As some noted, my
> question was specific to use on 40 and 20 meters.
>
>I now have some additional info to use in making a decision on which antenna
>and configuration to experiment with. Thanks to those who kindly shared their
>experience. For those who want to carry the thread forward.....great.
>
>73 John K4NP (only licensed for 47 years with all current DXCC entities
>worked)
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