[TowerTalk] Prop Pitch Indicator

[ve4xt at mts.net]

Mark the directions on the mast with an indelible marker: point a small video spycam at the markings.

The only way this indication could be off is if the antennas themselves rotate relative to the mast.

YMMV.

73, kelly
ve4xt
> 
> From: "Stan Stockton" <k5go at cox.net>
> Date: 2010/11/11 Thu PM 07:47:30 CST
> To: "Ro Grrr" <rogrrr at hotmail.com>, 
> 	<towertalk at contesting.com>
> Subject: Re: [TowerTalk] Prop Pitch Indicator
> 
> Roger,
> 
> Selsyns work well if they are mounted with a positive connection to 
> matching 1-1 gears.  I know that W3LPL has had a bunch of them in 
> operation that have worked well for him.  Some have had success with a 
> pulley on the selsyn shaft the same diameter as the mast and clamping a 
> small aircraft cable around the mast.
> 
> Other alternatives include setting up a 10 turn low resistance pot with 
> a 8-1 ratio between the pot and the mast so you have an extra turn on 
> either end.  Then you can have the same kind of setup you would see on a 
> Ham M type rotator using a meter.
> 
> I have had both and have had some problems with both - not because of 
> the technology but the implementation.  Currently have two of them that 
> need attention.
> 
> I believe the best solution is to buy a Green Heron Engineering/K7NV 
> control box.  Their indicator system uses a stationary reed switch and a 
> magnet that is on a piece that is mounted to the bottom of the motor 
> shaft.  You set the gear reduction ratio in the rotator box - 9576-1 for 
> a small prop pitch - and as it spins it will count turns and give you a 
> very accurate digital readout.  The point and shoot knob and electronic 
> limiting of rotation are other desirable features.  If you have a big 
> antenna you can also ramp up the motor, ramp it down, and run it full 
> out in between.  The control box is not cheap but in my opinion most 
> antennas that are big enough to require a prop pitch are worth spending 
> the extra money on that control box if you can afford it.  I have one 
> and wish I had two more.
> 
> Stan, K5GO
> 
> 
> ----- Original Message ----- 
> From: "Ro Grrr" <rogrrr at hotmail.com>
> To: <towertalk at contesting.com>
> Sent: Thursday, November 11, 2010 4:55 PM
> Subject: [TowerTalk] Prop Pitch Indicator
> 
> 
> 
> 
> 
> 
> 
> I have a prop pitch rotor I got from another ham but has no
> provisions for direction indication.
> 
> 
> I?ve heard about selsyns but I believe they require gearing to couple
> to the mast. His setup didn?t have anything like that and I don?t want 
> to go
> that route, anyway.
> 
> 
> How do I sense the direction ? I have thought about wrapping the mast 
> with
> something like a bar-code indicator as they do for digital readouts for 
> CNC
> machines but am in the dark there.
> 
> 
> Any suggestions ?
> 
> 
> 
> 
> Roger
> 
> 
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