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@cox.net>
> Date: 2010/11/11 Thu PM 07:47:30 CST
> To: "Ro Grrr" <rogrrr@hotmail.com>,
> <towertalk@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@hotmail.com>
> To: <towertalk@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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