On 11/18/2010 8:43 AM, Alex Malyava wrote:
> That's my point exactly.
> Whole project is to put up 30' of Rohn 25 bracketed to the (roof/ceiling
> joints) house at 20' level - that's it.
> My only plan was to put some little foundation to prevent it from sinking in
> dirt.
> No big antennas on it. MQ-26 for now which might become MA5B in some very
> distant future. The tower itself might become 40' - also in distant
> future... I have only 6+ feet between back of my house and fence, so there
> is not too much space for full-size turning radius beams hanging over my
> neighbor's house.
>
> It suppose to be "poor man beam on short tower" project, not "lets put a ton
> of concrete into a base" :)
Don't forget to properly drain the legs of the base.
Water trapped in the legs can cause premature failure due to rust and in
the climate up here the water will freeze and split the legs. That was
one of the reasons I chose to weld up a base using solid rod.
73
Roger (K8RI)
> Alex K2BB
>
>
> On Wed, Nov 17, 2010 at 8:08 PM, Roger (sub1)<sub1@rogerhalstead.com>wrote:
>
>> On 11/17/2010 4:17 PM, J.Gordon Beattie, Jr., W2TTT wrote:
>>> Ed,
>>> Do what the manufacturer requires and you won't have trouble.
>> Remember the ROHN "dirt base". I'm planning on 50' of 25G, bracketed to
>> the end of the shop at roughly 18'. There will be a Force 12 C19XR at
>> 50' and a WARC-7 at 60'. I'm using a 6' long, dirt base constructed out
>> of 1" solid rod with 6" X 10" X 1/8" steel face plates. The tower will
>> be guyed at roughly the 48' level using either 1200# test Phillystran or
>> 3/16 800# test braided poly rope. I have no qualms about climbing said
>> tower
>>> Ask yourself who is climbing this thing and do you want to save a couple
>> of
>>> dollars on concrete
>> At 30'?
>>> and then have to address an issue should there be a
>>> failure? There might be VHF and UHF antennas today and BIG YAGIS
>> TOMORROW.
>> In my case, if I go with larger antennas I'd replace the tower at that
>> time. However I have used 40' of 25G on a dirt base holding a 5L KLM 20
>> meter monobander, guyed at roughly the 38' level. It withstood nearly 70
>> mph winds plus a monster ice storm that took out over half a mile of
>> power line, Behind the house the power line had such a load of ice it
>> was only about 4' off the ground.
>>
>> However, I don't have room to swing the larger antennas on the small
>> tower any way so it's a moot point. Any thing big goes on the 45G
>> system which is guyed at 3 levels. The bottom two use 4000# test
>> Phillystran while the top tier uses 6000# test Philliystran. Guy
>> anchors are about 17,000# each.
>>> Don't take the risk.
>> Risk is relative and also depends on how risk tolerant the individual
>> is. I tend to be a risk taker with investments, but am quite
>> conservative when it comes to antennas, towers, and climbing.
>>
>> 73
>>
>> Roger (K8RI)
>>> Thanks& 73,
>>> Gordon Beattie, W2TTT
>>> 201.314.6964
>>>
>>>
>>> -----Original Message-----
>>> From: towertalk-bounces@contesting.com
>>> [mailto:towertalk-bounces@contesting.com] On Behalf Of Ed Swiderski,
>> KU4BP
>>> Sent: Wednesday, November 17, 2010 9:09 PM
>>> To: TowerTalk@contesting.com
>>> Subject: [TowerTalk] Short tower base question
>>>
>>>
>>> All,
>>>
>>> I have a couple full pieces and one cut piece of Rohn 25 that I'd like
>> put
>>> up against the house with a couple VHF antennas on it. (2m-16el and
>>> 432-18el) I plan on using a house bracket at about 3/4 of the height was
>>> wondering if a full size base is neccessary? I have been told by a good
>>> friend who used to work at installing towers that I can get away with a
>>> smaller than spec base in this situation.
>>>
>>> Thank you,
>>> Ed KU4BP
>>>
>>>
>>> _______________________________________________
>>>
>>>
>>>
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