This is a multi-part message in MIME format.
------=_NextPart_000_0022_01BE30D9.44057F40
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Part of a previous discussion went as follows:
>
>In a message dated 98-12-25 15:35:37 EST, alsopb@gloryroad.net writes:
>
>> In otherwords, does 15 sq foot rating assumes the antenna is at the =
top?
>
> No. The 15 sq.ft. is the capacity for the WHOLE tower, regardless =
of
>where the load(s) actually is.
>
>> Distributing the loading differently could get you extra capability?
>
> Nope.
>>
>> What failure mode is limiting and how does distributing the load
>> vertically impact it?
>
> It is typically the compression leg capacity that is the limiting
>factor.
>
>Cheers, Steve K7LXC
>
To the contrary, Steve, the elevation points where the antenna loads are
distributed do have a dramatic impact on the overall tower wind-load
capacity.
Just as shown by a simple illustration of, say, having two 10 lb. loads =
at
the end of a 5 ft. lever would be heavier than the same lever having one =
10 lb.
weight at the end and one at the 2 ft. mark, so also this is the same
principle involved with wind-loads near the top of a tower. OK, I know =
you
will not easily suffer my pedagogical attempts at analogies, so I have
something better for you-- much better. By reviewing our engineering
specs, you will not only prove this point mathmatically, but it will =
allow
anyone so inclined to figure the exact wind-load of any antenna array
configuration, so long as the tower section properties of your tower =
configuration
are known (our tower section properties are listed early on in the specs =
page).
The address is www.HeightsTowers.com/engspecs.htm .
By the way, to completely controvert some earlier allegations, however =
ingenuous, made earlier on this reflector as regards to my methods of =
tower engineering, I challenge anyone to find any errors, even clerical, =
in our method of engineering tower loads, as demonstrated on our =
Engineering Spec page. =20
=20
Unfortunately, a couple of the illustrative sketches in section 6.0 of =
the Engineering Specs do not show up that clearly on the browser at this =
time. Although they are not critical in the explanation of the =
formulas, I'll try to repair those soon. Meanwhile, you may find the =
given explanations informative.=20
=20
Happy holidays, y'all,=20
Drake Dimitry
>>visit our site at: www.HeightsTowers.com=20
------=_NextPart_000_0022_01BE30D9.44057F40
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
Part of a previous discussion went as = follows:
>
>In a=20 message dated 98-12-25 15:35:37 EST, alsopb@gloryroad.net=20 writes:
>
>> In otherwords, does 15 sq foot rating = assumes the=20 antenna is at the
top?
>
> No. The = 15 sq.ft.=20 is the capacity for the WHOLE tower,
regardless of
>where the = load(s)=20 actually is.
>
>> Distributing the loading = differently=20 could get you extra =
capability?
>
> =20 Nope.
>>
>> What failure mode is limiting and = how does=20 distributing the load
>> vertically impact=20 it?
>
> It is typically the=20 compression leg capacity that is the=20 limiting
>factor.
>
>Cheers, = Steve =20 K7LXC
>
To the contrary, Steve, the elevation points where = the=20 antenna loads are
distributed do have a dramatic impact on the = overall tower=20 wind-load
capacity.
Just as shown by a simple illustration of, = say,=20 having two 10 lb.
loads at
the end of a 5 ft. lever would be heavier = than the=20 same lever having
one 10 lb.
weight at the end and one at the 2 ft. = mark, so=20 also this is the same
principle involved with wind-loads near the top = of a=20 tower. OK, I
know you
will not easily suffer my pedagogical = attempts at=20 analogies, so I have
something better for you-- much = better. By=20 reviewing our engineering
specs, you will not only prove this point=20 mathmatically, but it will allow
anyone so inclined to figure the = exact=20 wind-load of any antenna array
configuration, so long as the tower = section=20 properties of your tower
configuration
are known (our tower section=20 properties are listed early on in the specs
page).
The address is www.HeightsTowers.com/= engspecs.htm=20 .
By the way, to completely controvert some = earlier=20 allegations, however
ingenuous, made earlier on this reflector as = regards to my=20 methods of
tower engineering, I challenge anyone to find any errors, = even=20
clerical, in our method of engineering tower loads, as demonstrated on =
our=20 Engineering Spec page.
Unfortunately, a couple of the illustrative = sketches in=20 section 6.0 of
the Engineering Specs do not show up that clearly on the = browser=20 at
this time. Although they are not critical in the explanation of = the=20
formulas, I'll try to repair those soon. Meanwhile, you may find = the
given=20 explanations informative.
Happy holidays, y'all,
Drake Dimitry
>>visit our site at: www.HeightsTowers.com
------=_NextPart_000_0022_01BE30D9.44057F40--
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|