Gedas,
DXE has .120 wall aluminum tubing in the larger sizes that skips every other
1/8" OD size when telescoping.
I would start with 3 feet of 2 inch X .120, then 6 foot pieces of 1.75, 1.5 and
1.25 (all .120 wall) and then 3 foot pieces of every size they have starting
with 1 inch down to 3/8. You won't be using 3 feet of the 3/8". This is good
for about 80 mph and will end up weighing about 18 pounds.
Less expensive and even lighter weight would be to start with a smaller size
and use longer lengths of smaller diameter stuff at the top. How strong do you
want it to be? If the wind speed is more than about 65 MPH at that low height
through the trees you probably have bigger problems than a bent 40m vertical.
73... Stan, K5GO
> On Jan 1, 2020, at 10:13 AM, Gedas <w8bya@mchsi.com> 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.
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|