[TowerTalk] Homebrew Rotators

[VE6JY Don Moman]

Direction readout on HB rotors:

The video camera is the way to go.  I had several up for 3 years outside in
the weather down to -40 degrees with no problems.  They are normally left on
24/7 and they generate a fair bit of heat and that may help in the colder
weather and prevent condensation issues.  They function fine in the midst of
multi-multi contest level RF too.

I have one camera at the bottom of each of the towers with stacks on them,
allowing me to see all the yagis and their positions, and letting me align
them precisely.  Night vision is minimal but a spotlight will let me
determine what is pointing where, as long it is not snowing or raining hard.
As progress comes, I will add more cameras nearer the tops of the stack.

On the other towers I have the cameras pointed at the mast, maybe 4 to 6"
away and focused on a part of the mast that has a 0-360 scale attached (just
handwritten with a Pentel white-out marker - these are superb for outdoor
marking on coax and the like, BYW).  One or two I/R leds near the camera
provide plenty of illumination for the camera - all these b/w LCD cameras
have good infrared response.

I'm using a variety of cameras purchased quite cheaply at Dayton. Typically
they cost in the 35 to 45$ US area.  12 volts at a bit over 100ma keeps most
of them happy.  The picture quality (baseband video) even over 800 feet or
more of coax is just fine.  RF modulators / wireless video senders are an
alternative if no coax exists.

I have used pots, 10 turn and instrumentation kind, rotary switches,
selsyns, and thought of other schemes but they all have more problems than
the video camera route.  And nothing beats seeing the antennas turning and
watching the progress (or lack thereof) of your homebrew rotor.  If the
camera is positioned so it can both see the mast and the mechanical section
of the rotor, it can sure aid in the diagnostic process too.  These little
cameras have a pretty wide angle lens and can see quite a bit.

Putting the cameras along the boom would give a nice scenic view but I sure
wouldn't want to check direction with them. Motion sickness is one thing
that comes to mind.  And out here, one tree kinda looks like the next
anyway.   And any guest ops are sure to have problems.

73 Don
VE6JY



>
> I donot know how things would perform in the outsied environment, but.  I
> understand some of the video comeras for computers are very inexpensive,
> say about US$25 or so?  I like the suggestion to put the camera along the
> boom, that way you will"see" what way the boom is pointing rather than at
> eh base looking at the boom.
>
> Just a comment, Chris opr VE7HCB
>
>
> At 09:34 AM 2001-11-02 -0500, Bill Coleman wrote:
>
> >On 11/2/01 3:51 AM, Zoltan.Pitman@libertel.nl at
> >Zoltan.Pitman@libertel.nl wrote:
> >
> > >Closed circuit TV camera for heading indication ?!?
> >
> >Yes, why not? Such a system isn't incredibly expensive. Black and White
> >cameras are available for less than $100 US dollars.
> >
> >It has the advantage that you always know which direction your beam is
> >pointed -- even if the mast slips in the rotator.
>


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