[TowerTalk] TH3MKII vs 3 element SteppIR

[Terrence R. Redding Ph.D.]

The biggest problem with bigger is the proximity of my tower layed over near
the house.  I originally laid it out to accommodate a cubical quad.  When
that went away in a hurricane I replaced it with a "storm" antenna, the
TH3MKIV.  Now, five years later I would like more antenna - and the SteppIR
seems like the right choice.  But the TH3MKIV reflectors already brush the
eve of the roof when I lay the tower down, and the SteppIR is considerably
longer in the elements.

That is the main concern.

Terry - W6LMJ


On 7/13/09 9:05 AM, "Mike" <nf4l_NO_SPAM at nf4l.com> wrote:

> Terry -
> I'm not sure if you mean to leave the dipole up or not. Get the 30/40M
> driven element, and do away with the dipole, and add a band.
> 
> Why do you care if it's bigger? Will it extend over your property line?
> If you're worried about Fla. winds, take a look at the pic on the cover
> of the manual.....
> I'm in Jacksonville, and so far my 4L has survived going on 6 years now.
> 
> Check the tower specs for wind load. It looks like the 30/40 element is
> 2 sq. ft. bringing the total to 8.1.
> 
> You could easily assemble it in a day. Be sure to read the manual at
> least 3 times before you start.
> 
> 73,
> Mike NF4L
> 
> Terrence R. Redding Ph.D. wrote:
>> I have a TH3MKII with a 30/17/12 dipole mounted five feet above the beam on
>> a 54 foot Tri-Ex tower.  I am thinking of replacing that with a 3 element
>> StepIR.  I am convinced it will be a step up in all cases.  However, I have
>> never seen a 3 element SteppIR and don't have a feel for whether I am
>> dramatically increasing the amount of stuff I have on top of my tower.
>> 
>> Has anyone done something like this?  I assume many have.  If so, did you
>> have the sense that you were putting more stuff in the air and increasing
>> the risk to the tower coming down in a storm.  Or was you sense that you
>> were reducing the wind profile and actually putting less in the air, and
>> thus reducing the likelihood that it all might come down in the wind?
>> 
>> In the pro vs cons, it appears the SteppIR weighs less and presents less
>> wind load.  However, the antenna is bigger, nearly four feet longer on each
>> side of the boom.
>> 
>>     Weight lb    Length ft    Width ft    Wind Load lbs    turning radius ft
>> TH3MKII    35    14    27.5    4.6/118    15.3
>> Dipole 12/17/30    20        29.56    '1.8/48    16
>>                 
>> StepIR 3 element    51    16    36    6.1    19.7
>>                 
>> I am also curious to know how long assembly takes.  I would hope I could
>> build the antenna during the week, and then drop the tower and install with
>> all cables and be back on the air on a Saturday.  Is that reasonable for one
>> guy?
>> 
>> Terry - W6LMJ West Palm Beach, Florida
>> 
>> 
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