[TowerTalk] Guying mast above rotor

[David Gilbert]

Matt didn't say 12 inches above the tower ... he said 12 feet ... and I 
totally disagree with the rest of your comments.  Assuming the tower 
itself is capable of handling the antenna load (taking into account the 
leverage of the mast), it is FAR FAR cheaper to simply use a mast rated 
for the job than it is to install another tower or rotate the existing 
tower.

I have a 70 foot heavy duty freestanding tower with 15 feet of 1/4 inch 
thick 2 inch diameter chromalloy mast sticking out of the top of the 
tower.  The mast holds up an OB16-3 three feet above the tower and an 
OB2-40 about twelve feet above the tower.  Those are decently large 
antennas ... MUCH larger than a 10m monobander.  I regularly (almost 
daily in the spring) get wind gusts on this southern Arizona hillside 
that exceed 80 mph and I've measured them as high as 100 mph (strong 
enough to strip the gears on my Prosistel PST-61D rotator) and the mast 
has held up fine after six years of that ordeal.  A similar mast would 
cost just over $500 last I checked, which is considerably cheaper and 
simpler than what you propose.

Dave   AB7E



On 2/12/2014 1:12 PM, Dan Cisson wrote:
> Matt....an opinion only... You are really not accomplishing much if 
> anything...You say you are guying the mast 12 inches out the top of 
> the tower ?? All you are doing at this point is asking a storm to bend 
> the mast above the guy ring...Long masts are asking for trouble, there 
> is a heck of a lot of leverage on the top of a long mast in high 
> winds...You could possibly be OK with a 6 meter beam atop the mast, or 
> a 2 meter beam, its a gamble !!. But if you put up an antenna that is 
> much bigger than a 10 meter yagi,, you are asking for PROBLEMS !!I 
> have took down too many of them in my days of tower work.  Other 
> alternatives are another tower(probally not an option for most hams).. 
> or fixed antennas down the tower...It is expensive, but you can rotate 
> the complete tower!! I would check with antenna manufactures and see 
> how close you can stack their antenna to other antennas on the same mast.
> It will be interesting to see what other opinions you get here on TT.. 
> Good Luck, and be CAREFUL !! ,,Dan N4GNR
> ----- Original Message ----- From: "Matt" <bluewaterpro at yahoo.com>
> To: <towertalk at contesting.com>
> Sent: Wednesday, February 12, 2014 2:45 PM
> Subject: [TowerTalk] Guying mast above rotor
>
>
>> I know the subject line sounds dumb,, but I have 15' of mast above my 
>> tower and live in South Florida. Read on...
>>
>> Im thinking of putting a guy ring at about 12' above the top of the 
>> tower, and, only in event of a severe storm, attach 3 guy wires, 
>> which would be anchored in concrete, the cables sitting on the 
>> ground, affixing them to the collar in event of storm.
>>
>> I've also thought of having  short guy wires permanently mounted on 
>> the guy ring collar, with the short guy cables running down the mast 
>> to the top of the tower.  Then i could climb up and attach the guy 
>> wires, if needed. No need for a bucket truck.
>>
>> I think this would provide additional survivability to the mast in 
>> heavy wind
>>
>> Any thoughts on this? Good idea, bad?
>>
>> Thanks/73
>>
>> Matt w1mbb