[TowerTalk] ATTention Tennedyne owners

[Jim Thomson]

Date: Wed, 30 Jan 2019 13:55:41 -0500 (GMT-05:00)
From: Dave Thompson <thompson at mindspring.com>
To: towertalk at contesting.com
Subject: [TowerTalk] ATTention Tennedyne owners


<The beam is mounted about 9 feet below the 2 el 40 Cushcraft .

<The tower guy said with the 20 foot 2" .25 aluminum mast I used that the extra spacing might cause the mast to bend. The 40 meter beam has an overhead strut that uses up almost 4 feet of the mast so 11 feet was the most I could separate the beams. 

<73 Dave K4JRB   


##  so which is it?    Is the Tennedyne   9 feet below the 40m yagi....  or is the Tennedyne  11 feet below the 40m yagi  ?   How much mast is inside the tower ?  How many thrust bearings are used ? 
How far above the top of the tower   is the Tennedyne  mounted ?   What rotor are you using ? 

##  Did  you  run the load on the mast calculator ??   Installing a 40m yagi  9 to  11 feet above the top of the tower is no small windload.   A  2 inch OD  x .25 inch wall  aluminum mast is not strong to start with.
Think of the portion of the mast  above the top of the tower as  a long torque wrench.   Then the  40m yagi ..in a wind, creates  the load.   This is all easily calculated out on mech mast software.  Then at least you will
know the max windload  the mast can handle...before it snaps..just above the  top of the tower. 

Jim   VE7RF