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Re: [TowerTalk] SteppIR problem

To: "James C. Garland" <>,<>
Subject: Re: [TowerTalk] SteppIR problem
From: "Mark Robinson" <>
Date: Sun, 10 Jun 2007 17:31:01 -0400
List-post: <>
I am wondering if you are having problems because you have a long run of 
control cable. Paralleling the control cable might be a useful experiment. 
If your voltage at the motor is really low will the motor take excessive 
current and trip out the power supply current limit.

I presume that you are not running a transmitter and coupling rf into the 
control cable in the long conduit run.

I know that these are off the wall suggestions but something is causing your 
problem and it may not be an obvious thing.


----- Original Message ----- 
From: "James C. Garland" <>
To: <>
Sent: Sunday, 10 June, 2007 5:12 PM
Subject: Re: [TowerTalk] SteppIR problem

> Bill, that's quite an interesting mystery! Evidently, you're overloading 
> the
> power supply and it's shutting down, so I agree with Jerry's assessment.
> However, from what I understand, the stepper motors are current driven, 
> not
> voltage driven. That means that even a short circuit in a pair of wires to
> one of the stepper motor windings shouldn't overload the power supply. And
> if you've checked all the resistances between pairs and they'r okay, and 
> if
> there's no resistance across pairs, then that pretty much rules out any
> problem with the antenna. If there was an antenna problem, then the 
> shutdown
> would occur always when the same motor was energized. But that's not what
> you're seeing.
> Did you check to make sure there's no resistance between any of the 
> control
> cable pairs and the control cable shield?
> Have you checked your AC line voltage? Your symptom could be explained if
> the voltage is too low. Also, by any chance is your power supply plugged
> into a GFI, UPS, or surge-protected circuit? One simple test would be to
> measure your AC line voltage when you power up the controller and see if 
> the
> voltage sags.  Also, if the power supply is plugged into an outlet strip,
> then you could try changing it: it might be a faulty surge suprressor or
> switch in the outlet switch with some resistance that's dropping your line
> voltage.
> Let us know what you learn, and good luck!
> Jim W8ZR
> -----Original Message-----
> From:
> [] On Behalf Of Bill Carnett
> Sent: Sunday, June 10, 2007 9:42 AM
> To:
> Subject: [TowerTalk] SteppIR problem
> Greetings to all Tower Talkers,
> A very wise man and fellow TT (K7LXC) suggested I post
> my challenge here to the group...maybe somebody will
> have a new idea that I've not explored.
> Last week we put up a new 4L SteppIR with a 40/30
> dipole.  The antenna is approximately 500 feet from
> the shack.  SteppIR control line is used, continously
> without any accessories inserted, running through 3
> inch conduit (not that that makes any difference).
> Prior to lifting it in the air I found that a problem
> existed.  When attempts were made to change bands or
> even frequency on the same band, the control box went
> dead.  Simultaneously, as the box died, the "on"
> indicator light on the pwr supply went out.  A second
> later the pwr light came back on; the led "lights" on
> the control box flashed once but the box remained off.
> The box could be turned back on, but the same
> sequence occurred if a band/freq change was attempted.
> Immediately all of the wiring and continuity was
> checked with the antenna...all ok.  Spoke with Jerry
> at SteppIR and we proceeded to change first control
> box....before I realized the pwr supply was
> change.
> The next step was to attempt to run each motor
> individually and in groups.  Each motor ran
> individually without problem.  Adding the 2nd and 3rd
> motor caused no problems....the yagi functioned fine.
> The addition of the 4th motor (didn't matter which
> sequence), consistently killed the antenna. On
> occassion it would all seem to work for a couple of
> band changes but never more than 1 or 2 minutes - with
> all 4 motors running. So, with up to 3 motors
> running...all ok, with all 4, no go.  However, this is
> a 4 element yagi.  After speaking again with Jerry, I
> was reassured that the problem was simply a power
> supply and all will work fine....thus the long
> scheduled antenna raising event went forward as
> scheduled.  Needless-to-say, the replacement power
> supply did not correct the problem.
> Prior to erecting the yagi I extended the elements to
> 14150 so it can be used as a monobander...but that
> will only bring temporary happiness.  A power supply
> (3rd) was "hand picked" by the SteppIR engineers,
> sent, and tested this morning.  Basically the same
> problem.  It did seem to work briefly then shut
> down....exactly the same as before.
> So, I'm looking for ideas that have been overlooked.
> Yes, I should have listened to my gut, rather than the
> "experts" and canceled the raising until all problems
> were fixed, but that can't be undone.  If this beast
> must be lowered, I'm a bit reluctant to put it back up
> after this experience.  Yes, all antennas have
> problems but it would be less $$ to replace it at the
> time of lowering rather then taking down, bring the
> crane back and forth, etc.
> Sorry for the long-windedness of this but any and all
> thoughts are appreciated!
> 73, Bill
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