[TowerTalk] A couple of 18HT questions

Patrick Greenlee patrick_g at windstream.net
Fri Dec 19 15:56:17 EST 2014


Gary, You misunderstand my meaning.  Another try... Hy-Gain has sold 
Hy-Towers since the 50's and I know of no failures due to corrosion of 
those tubes.  Has there been one?  Anyway, those telling us of the the 
dangers caused by "chemistry" are like the aerodynamics types claiming 
the bumble bee couldn't fly.  The bee flies and the tower doesn't fall 
down due to corrosion of the aluminum due to concrete contact.  Ground 
truth trumps speculation however informed.

Oh, by the way, I did take that physics class and a bunch of others and 
was a physicist before finding true religion (computers) and getting a 
BSCS and MS softwarre engineering.

I'm the guy who pokes pins in others balloons, recommending 
(allegorically) that rather than pontificate and guestimate at the
number of angels dancing on the head of a pin, get a lens and count the 
little buggers!  Fact trumps theory.  I don't deny that the concrete 
corrodes the aluminum but given the facts related to the number of 
towers failing, apparently the corrosion isn't significant. There are 
towers out there with aluminum legs in concrete for over 60 years.  If 
corrosion was a significant issue you'd think there would be eHam 
postings mentioning that.

Patrick     NJ5G




On 12/17/2014 9:13 PM, Gary Schafer wrote:
> You should have taken the physics course too. :>) The old "bumble bee
> shouldn't be able to fly" is an old wives tale that has been around for
> ages.
>
> 73
> Gary  K4FMX
>
>> -----Original Message-----
>> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
>> Patrick Greenlee
>> Sent: Wednesday, December 17, 2014 8:00 PM
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] A couple of 18HT questions
>>
>> Yeah, I had the requisite year of freshman chemistry too but lets get
>> real.  Hy-Gain has been making these antennas for how long? They have
>> been putting aluminum into concrete for how long?  Anyone ever here of a
>> failure due to corrosion of the aluminum?  I don't have a dog in this
>> fight as I replaced the thick walled aluminum tubes with solid steel
>> bars as in mounting on the roof of my barn I wanted to weld the three
>> "posts" to some of my custom base components (steel) and I'm not good at
>> welding steel to aluminum.  I still have the aluminum tubes awaiting a
>> use to present itself.
>>
>> Somehow I am reminded of the old story of the bumble bee and the
>> aerodynamicists. :-) ;-) :-D
>>
>> Patrick   NJ5G
>>
>>
>> On 12/17/2014 3:36 PM, L L bahr wrote:
>>> I have had my 18HT up for 30 years with aluminum tubes in the
>> concrete. I see no signs of deterioration.  That's good enough for me.
>>> Lee, w0vt
>>>
>>>
>>>
>>>
>>>
>>>    > You do not want concrete in contact with aluminum! It will eat up
>> the
>>>> aluminum. Even aluminum windows come with a warning to not let the
>> brick
>>>> mortar come in contact with the aluminum frame when installing.
>>>> After the concrete is set and dried it may be ok then, not sure.
>>>>
>>>> 73
>>> Yes indeed.. Aluminum is readily attacked by most acids and bases: the
>>> surface oxide helps a lot, and, of course, a chemical conversion
>> coating
>>> (anodize, alodine) would too. BUT, a scratch in the coating provides a
>>> nice surface to be attacked.
>>>
>>> ALuminum is attacked by most basic hydroxides (e.g. sodium hydroxide,
>>> lye, is used to etch aluminum panels).. It is a way to make hydrogen
>>> gas, in fact.
>>>
>>> Mortar is a mixture of quicklime (CaO) and sand, for the most part,
>> and
>>> when you add water to it (slaking the lime) it forms Calcium Hydroxide
>>> (Ca (OH)2).
>>>
>>> Concrete has similar chemistry.
>>>
>>> So, yes.. keep your aluminum out of the concrete footing.
>>>
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>



More information about the TowerTalk mailing list