Subject: Re: Topband: dipole height
RDF is the key point to improve signal noise, not gain. Vertical or low
dipole has very or none directivity, so low RDF or directivity does not
improve signal noise.
In general, this is the case, but it is not always true.
Since I started using RDF, let me
James Wolf wrote:
In general, this is the case, but it is not always true. Consider that you
can have an antenna with a high RDF number, but at the same time has a
pattern where rear lobe positions favor the optimum elevation angles for
arriving propagated atmospheric noise. If you look at
K4SAV wrote:
Compare that to a 1 wavelength Beverage which is about 7.9 dB.
Sorry, I gave the number for a 1/2 wavelength Beverage not a one
wavelength. The one wavelength Beverage is 8.6 dB and the 1/2
wavelength Beverage is 7.9 dB.
Jerry, K4SAV
That's very true. Consider the K9AY. The RDF is about 7.7. Compare that
to a 1 wavelength Beverage which is about 7.9 dB. The K9AY has a deep
null in the 180 degree direction at the right elevation angle, but 45
degrees off that rear direction the signal is down only 10 dB. The RDF
number
I guess it's too early in the morning. I also misquoted the 1/2
wavelength Beverage RDF number. W8JI has a table with RDF numbers here:
http://www.w8ji.com/receiving.htm
Another example of surprising numbers happens to be my EWE array. The
RDF number is 11.3 dB. The front to back is 17 dB.
There is a third figure of merit name for small receiving arrays that came
out of Syracuse University Research Corporation in 1967. It was
called SNIF for Signal to Noise Improvement Factor. A term apparently
coined by the author, Dr Martin Fournier. His report uses this term
to describe the
ZR wrote:
15 and 60M and run comparisons for awhile. In areas where countries are
tightly packed a dipole may be a good choice.
Carl
KM1H
I had full size 160M dipoles (not inverted vees) up at 9 meters and
18 meters for about six months and did a lot of A/B'ing of them.
On receive, there was
Hi Rick
I had full size 160M dipoles (not inverted vees) up at 9 meters and
18 meters for about six months and did a lot of A/B'ing of them.
On receive, there was never any difference in audible S/N ratio.
This result is 100% sure to happen. Any time you have more than one resonant
antenna,
Hi it's an interesting discussion about the dipoles. I want to put up an
inverted vee dipole for 160. I can put the apex at 15,30,45 or 60m and have
90 degree apex angle. The ground is very good and I am right on the
magnetic equator.
I'm sure what works here is different for you, but I
N4IS wrote:
Hi Rick
I had full size 160M dipoles (not inverted vees) up at 9 meters and
18 meters for about six months and did a lot of A/B'ing of them.
On receive, there was never any difference in audible S/N ratio.
This result is 100% sure to happen. Any time you have more than one
RDF is the key point to improve signal noise, not gain. Vertical or low
dipole has very or none directivity, so low RDF or directivity does not
improve signal noise.
In general, this is the case, but it is not always true. Consider that you
can have an antenna with a high RDF number, but at
RDF is the key point to improve signal noise, not gain. Vertical or low
dipole has very or none directivity, so low RDF or directivity does not
improve signal noise.
In general, this is the case, but it is not always true.
Since I started using RDF, let me explain what it really is.
RDF is
Jim
high RDF number with significant lobes off the back that are only 10 dB down
from the main signal
There is no high RDF with lobes 10 db down, or one or another, not both at
the same time.
Regards
JCarlos
N4IS
___
Topband reflector -
15 and 60M and run comparisons for awhile. In areas where countries are
tightly packed a dipole may be a good choice.
Carl
KM1H
- Original Message -
From: Bob Kupps n...@yahoo.com
To: topband topband@contesting.com
Sent: Monday, October 29, 2012 5:38 AM
Subject: Topband: dipole
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