×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Antenna Deflection Requirement

Antenna Deflection Requirement

Antenna Deflection Requirement

(OP)
Hello-

I wonder if some of you RISA Tower users or other experts can help me understand a requirement. The requirement states "maximum sway of 0.4 degrees from the top or 2% of the height, whichever is less". I can certainly calculate the deflection due to wind and compare to 2% of height. I am asking about the meaning of sway in degrees from the top. Is that the calculated slope of the deflected shape? I see that RISA calculates a "tilt", but I don't know physically what that means (not a user). Perhaps it's the same thing?

Thanks

rd78

RE: Antenna Deflection Requirement

Just take the deflection of the two top most nodes and calculate the deflection angle from that.  

RE: Antenna Deflection Requirement

TIA-222-G defines sway as the angular rotation of an antenna beam path in the local vertical plane of the antenna from the no load position.  It is normally measured at service load condition rather than an extreme load condition.  So it has to do with slope rather than deflection.

The 0.4 degrees would be a sway limit, but the 2% would be a deflection limit.

According to the RISA TOWER manual, they call sway "tilt".

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources