If this is a temporary operation why not guy to vehicle, tree, telephone,
building or the like?
Ray, N6VR
On Thu, Jul 11, 2013 at 11:32 PM, K8RI <K8RI-on-TowerTalk@tm.net> wrote:
> On 7/12/2013 12:31 AM, Grant Saviers wrote:
>
>> "with guys of course", the only limit is the spring rate of the trailer
>> and the load rating of the tires. The guy down force can be
>> substantial, so you might need to block the trailer so the load is not
>> on the tires/springs. Finding something to tie the guys to will be a
>> huge problem.
>>
>> I have a Will-Burt 42' pneumatic mast guyed into a trailer or the bed of
>> my 3/4T truck. The mast is rated for 10 sq ft antenna, 140lb weight, at
>> 60mph fully extended. My calcs show this load will tip over my 3/4T 8'
>> bed extended cab 4WD truck (5000#). For the hydraulic dump 10K# GVW
>> dual axle trailer, which weighs 2300#, I have 40" long outriggers at
>> each corner of the 6'x10' bed and 3500lb trailer jacks at the end of
>> each outrigger. The outrigger beams are not sized for the max tower
>> load/wind speed and enable the trailer to be leveled so the tower is
>> vertical. My plan is to not have the mast up in more than 35mph winds
>> which is the max load for the beam section/cantilever length I used for
>> the outriggers. Otherwise, the outriggers need to be long and heavy and
>> probably need to be made as a truss.
>>
>> This mast on the trailer played well at Field Day with a CC A4S at the
>> top. btw the air pressure was only 12psi for full mast extension with
>> the A4S and Yaesu rotator.
>>
>> There are pickup pulled boat trailers from 500# to 20,000# capacity, so
>> you need to do some calcs to size the max tower loads. Generally, since
>> the legal max width without oversize permits is 8'6", outriggers will be
>> needed and that is another structural design problem.
>>
>> Trailer mounted crank ups and pneumatic masts that go to 100' are
>> mounted on trailers, but at that height they are guyed. I can only
>> guess at how one would install the "temporary" guy anchors. Of course
>> these are purpose built heavy duty trailers with truss outriggers, plus
>> the guys. I checked out a trailer mounted 100 footer at a surplus
>> auction last fall. A beautiful piece of engineering was reduced to
>> scrap aluminum when a hoist cable failed.
>>
>>
> I agree with Grant, but would use a simple base with rods driven in at
> each corner. The plate would support it and the rods would supply lateral
> stability. If put up in the conventional manner and liberal use of strong
> temporary guys. I use Phillystran.
>
> The guy anchors are a serious problem. If they are going to hold much,
> I'd use at least 3/4" steel rod with at least 4" wide plates welded on the
> sides. I'd use an air hammer to drive the rods in at a 90 degree angle to
> the guys. Getting them out is another problem.
>
> Better yet a crane would be handy for setting it, but I'm assuming one is
> not available. With good guys and anchors plus good nerves, it's as strong
> as a permanent tower.
>
> Just make sure the guys are tensioned before putting up the next section
> and those anchors are well seated in solis soil. Sand won't do it!
>
> 73
>
> Roger (K8RI)
>
>
> Grant KZ1W
>>
>>
>> On 7/11/2013 6:44 PM, Eric Cary wrote:
>>
>>> I have been talking with some friends about setting up a temporary
>>> tower on a trailer something like a boat trailer.
>>>
>>> Something like this:
>>>
>>> http://home.comcast.net/~k8cc/**images/100_0137.JPG<http://home.comcast.net/~k8cc/images/100_0137.JPG>
>>>
>>> http://home.comcast.net/~k8cc/**images/100_0816.JPG<http://home.comcast.net/~k8cc/images/100_0816.JPG>
>>>
>>> What is the highest you would go with a Rohn 25 or 45 tower with guys
>>> of course?
>>>
>>> 73, Eric N3TD "Touch Down!!!"
>>> ______________________________**_________________
>>>
>>>
>>>
>>> ______________________________**_________________
>>> TowerTalk mailing list
>>> TowerTalk@contesting.com
>>> http://lists.contesting.com/**mailman/listinfo/towertalk<http://lists.contesting.com/mailman/listinfo/towertalk>
>>>
>>>
>> ______________________________**_________________
>>
>>
>>
>> ______________________________**_________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/**mailman/listinfo/towertalk<http://lists.contesting.com/mailman/listinfo/towertalk>
>>
>
>
> ______________________________**_________________
>
>
>
> ______________________________**_________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/**mailman/listinfo/towertalk<http://lists.contesting.com/mailman/listinfo/towertalk>
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|
