Antenna Strap Mounts on Poles, Chimneys 1

[Jackcsh]

Many antennas are now straped to poles, chimneys and other structures. Friction seems to be the major supporting force. How are these mounts analyzed to take into account friction? Finite element analysis,conservative assumptions, etc?

 

[csd72]

Jackcsh,

Like many things in this world I doubt that there is any engineering involved in these.

 

[Jackcsh]

CSD72,

Thanks for the quick response. It seems to me that it would be a rather complex problem with wind loads in many directions, dead loads, moments, etc. There are a lot of these out there. I haven't heard of any comming down. As engineers do we just take the supplier's word that they function as described in the catalogs?

 

[csd72]

This is just one of a number of things that would be hard to justify with numbers.

But because they work there has been no issues with them going without engineering.

 

[Robertmet]

Many small antennas are put on chimneys without engineering and have no structural problems. Larger antennas are sometimes installed without engineering and some of these have guy wires . But these larger antennas put loads on the chimney that were not meant to be !The other problem is RF. Typical houses today have so many electronic gadgets that are sources of RFI, that house mounted antennas are a bad idea.One source suggests at least 5m from the house to eliminate this. As a Ham and engineer I say except for the smallest ones , keep antennas of the chimney and off the roof !!!