[TowerTalk] Which Vertical is More Robust ?

[Gedas]

Hi Rick es HNY !

TU for that advice. I need to look up the weight of the heavier duty 
fence pipe. As these are going to be elevated verticals which I "pivot" 
into place by myself I need to look at what the total weight will be. I 
have about 8' of 6x6 set in the ground then use a wooden frame that 
cradles around the 6x6 and pivots the verticals into place. Kinda hard 
to explain but it will put the feedpoint at around 10' off the ground, 
then of course the length of the vertical. So I should be able to walk 
it up into place. Will check it out TU.

But let me ask my question again, is it better to go with a larger dia 
pipe (even if it has a greater wind load) or better to go with a smaller 
dia tubing with less wind load? Assuming the wall thickness is the same 
for all the members.

Gedas, W8BYA

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.

On 1/1/2020 12:23 PM, Richard (Rick) Karlquist wrote:
> Recommend that you consider chain link fence "top rail" instead
> of EMT.  Get the "1 7/8 inch" OD variety.  It is the same
> diameter as "1 1/2 inch" water pipe.  It is actually intended
> to be structural.  There is also a "1 3/8 inch" OD variety than
> you can telescope.  It is the same diameter as "1 inch"
> water pipe.
>
> Rick N6RK
>
> On 1/1/2020 8:13 AM, Gedas wrote:
>> HNY to all !
>>
>> I cannot think of a better time to start a new 40m phased vertical 
>> project then the dead of winter with snow on the ground (as usual I 
>> could not get to it during the summer or fall).
>>
>> Anyway, I have drawn up two possibilities for a pair of 33' self 
>> supporting verticals. Both start out with a 10' length of EMT but one 
>> choice starts out with a larger dia then the other before I switch 
>> over to tapering aluminum sections.
>>
>> A) Starts out with a 10' length of 1-1/4" EMT followed by tapering 5' 
>> sections of aluminum tubing (4' long exposed, 1' inside the previous 
>> lower section) until the very top length section which will be 3/4" 
>> OD dia. These will be standard DX engineering aluminum tubes.
>>
>> B) Starts out with a 10' length of 1-1/2" EMT, then a 5' length of 
>> 1-1/4" dia of EMT (4' long exposed, 1' inside the previous section of 
>> EMT) then followed by tapering 5' sections of aluminum tubing as 
>> above. The only difference being this choice would end up using 1" 
>> aluminum tubing as the very top piece.
>>
>> So the obvious difference between the two are that choice A) uses 
>> just one length of thinner EMT and overall thinner aluminum tubing 
>> sections to the top while choice B) uses 2 lengths of larger dia EMT 
>> and then larger dia aluminum tubing to the very top.
>>
>> I do not have the software to analyze choice A) vs. choice B) in a 
>> high wind situation. I am uncertain if the stronger, larger dia 
>> tubing with it's higher wind load will be a plus or a minus in the 
>> end to it's overall strength. Any thoughts or comments on which one 
>> will survive better during heavy wind conditions? TU
>>
>> Gedas, W8BYA
>>
>> Gallery at http://w8bya.com
>> Light travels faster than sound....
>> This is why some people appear bright until you hear them speak.
>>
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