[TowerTalk] A couple of 18HT questions

Fri Dec 19 18:17:59 EST 2014

The original Hy-Tower installations had NO concrete ... the aluminum  
legs were bolted into a corrugated steel casing that was cylindrical  
in shape and that was buried in compacted soil at the base.

Installed four Hy-Towers with that configuration over the years ..  
(NONE at my QTH) ... but think that would still work fine.

73
Don
N8DE

Quoting Gary Schafer <garyschafer at largeriver.net>:

> Hi Patrick,
>
> No I don't think that I misunderstood your meaning but maybe you
> misunderstood mine. :>)
> The old rumor about aerodynamic engineers claiming that the bumble bee
> shouldn't be able to fly, is just that- a rumor. No aerodynamic engineer
> with any credibility ever made that claim that I know of. But I don't doubt
> that some not so well informed people many years ago started that rumor and
> it has persisted to this day and some people still hang their hat on that as
> an indication that "science is not always right".
>
> As far as no towers falling down because of aluminum imbedded into concrete,
> I don't know about that.
> But I can tell you that I don't have any elephant repellant around my house
> and I have never been attacked by one so it must be working.
>
> "Fact trumps theory" is another good one. The answer to that is if fact and
> theory do not agree then one of them is wrong.
>
> I don't know of any aluminum towers with their legs planted in concrete but
> then I haven't necessarily seen everything.
> I did work for Motorola for a few years issuing sub contracts for tower
> installations for new systems. Never did I see aluminum in concrete.
>
> If you talk to any concrete engineer I am sure that they would tell you all
> about concrete and aluminum.
>
> No, you are not poking pins into my balloon as I don't have one. :>)
>
> Yes I understand what you are saying about some of these tubes holding up
> 18HT's for a long time.
> All I am saying is I wouldn't put anything aluminum into concrete.
> If you or others feel comfortable doing so it's ok with me.
>
> I am interested in how well the hytower works on the metal roof. I have one
> laying around that I was thinking about trying, mounting it on another tower
> section on the ground and the base of the hytower at roof level connected to
> it as a ground plane.
>
> 73
> Gary K4FMX
>
>> -----Original Message-----
>> From: Patrick Greenlee [mailto:patrick_g at windstream.net]
>> Sent: Friday, December 19, 2014 2:56 PM
>> To: Gary Schafer; towertalk at contesting.com
>> Subject: Re: [TowerTalk] A couple of 18HT questions
>>
>> 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.
>> >>>
>> >>> _______________________________________________
>> >>>
>> >>>
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>
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