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Re: [TowerTalk] What rotor should I use

To: towertalk@contesting.com
Subject: Re: [TowerTalk] What rotor should I use
From: K8RI <K8RI-on-TowerTalk@tm.net>
Date: Thu, 27 Jun 2013 12:41:15 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
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@contesting.com] On Behalf Of Joe
Nuccio
Sent: Thursday, June 27, 2013 5:29 AM
To: Chris Pinholster
Cc: towertalk@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@mac.com>
To: Joe Nuccio <k4nyy@yahoo.com>
Cc: "towertalk@contesting.com" <towertalk@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@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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