You could model the antenna with the dimensions you have and get a good idea
of how the pattern would look with the antenna "flat" and with the center
higher than the ends. Obviously, the pattern will vary from band to band.
I use two OCFs and one is flat and one is in a slight inverted vee form and
oriented in a different direction. They both work fine but obviously have
different patterns on different bands,
I just switch between the two and choose whichever antenna gives the best
signal from whatever station I am listening to.
There are so many variables to this with all the different stateside and DX
signals that it is (in my opinion) a waste of time to try to obsess
endlessly about the flat or inverted vee form unless you know you want to
concentrate on a certain distance and path on specific bands. .
-------------------
Wes Attaway (N5WA)
(318) 393-3289 - Shreveport, LA
Computer/Cellphone Forensics
AttawayForensics.com
-------------------
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Ron
Young
Sent: Thursday, December 08, 2016 6:30 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] OCF Dipole Questions
Mike, it is a dipole. No matter how it is fed it is a dipole. Where you
place the OCF point (which end is where) is what is most convenient for coax
to shack.
Yes the antenna might work best flat but just get it up as straight and high
as possible. Turn on the radio and have some fun.
The directional properties of a multi band dipole are complex depending on
what band and how high. Again, put it up, open a beer, fire up the rig and
have some fun. In very broad terms, on 80 it is s dipole with max radiation
broadside, minimum off the ends. If inverted bee it is almost
omnidirectional. As you go higher in frequency the broadside lobes start to
split and move more toward the ends. On 20 meters it might look like a
clover leaf birds eye view. As you get up to 10 meters the lobes pull even
more toward the ends of the dipole with lots of sharp lobes off the side.
Buy a copy of the ARRL Antenna Book (any year) and learn about antenna smoke
and mirrors ;-)
73,
Ron W8RJL
62 years of ham radio fun.
Sent from my iPhone
> On Dec 8, 2016, at 5:13 PM, Mike Ryan <mryan001@tampabay.rr.com> wrote:
>
> A local here is about to put an offset center fed dipole up in the air. I
> think this antenna claims to work 10-80m. This is most likely going to be
> in the 40-45ft high range at best. A couple of questions came to mind when
> he mentioned that this was going to go up.
>
> If one end is in a tree, the other off a tower or some other support
> structure such as a tower, WHICH end would be in the tree..the SHORTER
> section or the LONGER section.does it matter?..(should the short end be in
> the tree or the long end?) .again, does it matter?
>
> The manufacturer had recommended the antenna be installed FLAT and not as
an
> inverted vee. At the aforementioned height, should this make a difference?
>
> At the aforementioned height, will the antenna have broadside properties
or
> more unidirectional?
>
> Start the flames.thanks for reading in any event. - Mike
>
> _______________________________________________
>
>
>
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