[TowerTalk] What rotor should I use

Thu Jun 27 12:41:15 EDT 2013

On 6/27/2013 11:58 AM, Dick Dievendorff wrote:
> Maybe a different rotator controller with a different ramp-down speed
> control could be helpful.  I really like the Green Heron controller that
> came with my K7NV Prop Pitch...
>
> 73 de Dick, K6KR
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Joe
> Nuccio
> Sent: Thursday, June 27, 2013 5:29 AM
> To: Chris Pinholster
> Cc: towertalk at contesting.com
> Subject: Re: [TowerTalk] What rotor should I use
>
> Hi Chris,
>
> Thanks for the input and your experience.
>
>
> The concern seems to that the 36' elements on the SeppIR start 'whipping'
> back and forth while the antenna is being rotated which puts a lot of stress
> on the gears when it comes to a stop. Apparently, this 'whipping' action is
> not of a concern on large beams made out of aluminum.
>

Oscillation is always a concern on large beams. Full size 5 and 6L KLMs 
can put a tremendous strain on the rotator, but nothing compared to full 
size 40 m monobanders.

I think you will find many SteppIRs out there being turned by Ham IVs 
and larger.

Even the 4L only weighs 100#. That's hefty and it is a combination of 
mass and length of arm that determines force.  The 3L with with a 16' 
boom and 51# weight is not massive and within the ratings of many 
rotators including the Ham IV.

The Ham IV has very little torque, BUT it has a wedge brake. With the 
little StepIR, I'd not be concerned about the rotator's capabilities, 
but I would have concern about the antenna for those operators who tend 
to just let go of the rotation control and brake.

There is a fully loaded StepIR  (40 through 6 meters) about two blocks 
from me and I believe he is using either the Ham IV or tail twister.
He monitors this list occasionally and might comment.

I think the direction, or concern on here is mainly misdirected. Both 
rotators are plenty capable of turning any of the StepIRs.  The point 
that needs to be addressed (and has a couple of times) is the effects on 
the antenna.

Add a controller that ramps the speed up and down and comes to a stop 
before engaging the brake and there should be no problem.

Although I use one, as I've said before, I do not like rotators that use 
a wedge brake. When I had the "array" up, the Ham series (including the 
TT) lacked torque and holding power when the brake was disengaged. I 
pressed the brake release and then the direction with only a fraction of 
a second in between. Even then the wind had given the antennas enough 
energy that the rotator could not over come (stop) it and go the other 
direction.

Put a wrench just large enough to be comfortable on either the Ham IV or 
tail twister, release the brake and you can easily spin the thing with 
one hand faster than its normal speed. I tore the guts out of one TT and 
two IVs while waiting for a dual worm gear drive rotator for the array. 
http://www.rogerhalstead.com/ham_files/Tower29.htm

These rotators have far more than enough power to turn and hold even the 
larger StepIR, but the do need to ramp the speed up and down.  How they 
do in the wind might be another story.  I'm not willing to only operate 
when the wind conditions are right.  Be concerned about the antenna, not 
the rotator.

When spending that much money on an antenna, I'd go a little extra for a 
good rotator.

73 and good luck.

>
> 73,  Joe  K4NYY
>
>
>
> ________________________________
>   From: Chris Pinholster <k4win at mac.com>
> To: Joe Nuccio <k4nyy at yahoo.com>
> Cc: "towertalk at contesting.com" <towertalk at contesting.com>
> Sent: Wednesday, June 26, 2013 9:10 PM
> Subject: Re: [TowerTalk] What rotor should I use
>
>
> Joe,
> I have a Force 12C4 on my MA-40 and use a Yaesu 2800 SDX. Works fine for the
> last five years.
> Of course YMMV.
>
> Chris  K4WIN
>
> Sent from my iPad
>
> On Jun 25, 2013, at 12:51 PM, Joe Nuccio <k4nyy at yahoo.com> wrote:
>
>> I have a US Tower MA-40, a MARB and MAF. I also have a SteppIR
>> 3-element
>>
>> beam. What rotor do I need?
>>
>>
>> One knowledgeable person about rotors has suggested thatSteppIR's put
>> a
>>
>> lot of torque back and forth on rotors. He thinks a HAM-IV will
>> getdestroyed and a t2x is marginal for the 3 elSteppIR because of the
>> 16' boom and 36'
>>
>> long elements even when mounted inside a tower on a rotor plate.  He
>> wonders
>>
>> if a t2x can handle the rotation of the MA-40 tower and the SteppIR as
>> well. He knows of many people using the MA-40 rotatable tower as I
>> want to do, but, they aren't adding a SteppIR on top. He suggests abigger
> rotor or smaller antenna.
>>
>> .
>>
>> I know some people who are using a HAM-IV to rotate a MA-40 tower,
>> but, they do have smaller beams. Please let me have your experiences and
> suggestions.
>>
>> 73  Joe  K4NYY
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
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