G8MNY > TECH 07.06.25 09:15z 124 Lines 4815 Bytes #165 (0) @ WW
BID : 34271_GB7CIP
Subj: Rotator 12V /P
Path: ED1ZAC<ED1ZAC<GB7CIP
Sent: 250607/0909Z @:GB7CIP.#32.GBR.EURO #:34271 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (Updated Jun 07)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
This I built from an old Army 24V motor gearbox system & 360ø AC pot, bought
new at rally many years ago. Although the same hardware may not be available
other homebrew solutions may make this information useful.
_______________________ Thread º º tube to fit
³ ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ bolt hole-ºnº inside /P pole
³ ³ edgewise meter ³ ³ __º~º__
³oÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙo³ ³ ³Rotator with
³ Left< o >Right ³ ³ ³geared DC motor
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ 5 Wire Cable ³_______³
with plugs & sockets ³_______³360ø Pot
=========
flat base plate
DIAGRAM
Non locking centre
off change over switch
+12-15V >ÄÄÂÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄo o o-0V
³ ³ \______________________* *____ Rotator
³ 220R ______________________* *____ DC motor
12R ³ /
³ ³ 0V-o o o+12V 5 way
³ ³ Cable
5V ÃÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ* *ÄÄÄÄ¿
Meter _³_ 1K ³
Lamp /_\' ³ .ÄÄÄÄ. ³
³ 9V³ 1K 10K /large \ 5K
³ ³ Preset<ÄÄÄÄCalÄÄÄÂÄ(centre 0)ÄÂÄ* *ÄÄ>Rotator
5V ³ Zero pot Preset ³ \ meter/ ³ Pot
Meter ³ ³ ³ 'ÄÄÄÄ' ³ ³
Lamp ³ 1K(not for a) ÀÄÄÄÄÄÄÄ´ÃÄÄÄÙ ³
³ ³ ³(normal meter) 100uF ³
0V >ÄÄÁÄÄÄÄÁÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ* *ÄÄÄÄÙ
plugs & sockets
MOTOR CONTROL
The simple circuit uses just a non locking change over switch to power the
under run low torque motor & gearbox, clockwise or anti-clockwise.
An under power rotator is useful for /P work as there is less chance of
damaging fouled cables or guys etc. My rotator can be left stalled with no
motor dammage, as it only draws 50mA.
Note, you do not normally need speed for aerial rotation so a well geared down
motor is best!
RF suppression of the motor may also be needed if you want to beam up on weak
signals, try adding caps like 1n, u1, 1u etc. across brushes & to motor chassis
as well as series chokes etc.
10uH
ÄÄÂÄÄ((()ÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄ¿
³ ³ ³ ³
³ u1 === u1 ß ³
=== ÃÄÄÄÄ¿ <MOTOR> === u1
³ u1 === _³_ Ü ³
³ ³ //// ³ ³
ÄÄÁÄÄ((()ÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÙ
10uH
I do not earth the rotator through the control cable so there are no DC loops.
Mast earth is provided by a clip on a flexable lead to a ground stake if
needed.
POSITION INDICATION
My rotator pot was originally a 3 phase AC pot with 2 wipers & 3 pot taps,
which was reconfigured to a straight forward 360ø track pot with no stops.
The pot is powered by a shunt regulated 9V supply. A large sensitive centre
zero meter is used (ñ1mA), but a non centre zero one can also be used.
The meter is damped by a 100uF so that a scratchy rotator pot does not cause
wild readings. The zero preset pot sets the meter zero point (centre or side) &
the cal preset pot sets the full scale indication.
If a rotator is used with stops then a geared down normal pot (e.g. 270ø) can
be used in the rotator & any unused track compensated for by this circuit.
My meter scale is marked.. as my rotator has no stops, so the needle swings
from SOUTH to SOUTH marks quickly on overturn.
S W N E S
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Physical calibration when portable is done by just lifting the rotator & mast
turning whole thing & putting it back down (a brain teaser as to which
direction!). Any tendency for the rotator to spin on the ground is solved
either by a few tent pegs into grass, or placed on a sponge sheet if on tarmac.
MAST CONNECTION
My system for this rotator uses a hole in the mast pole that allows a screw to
be put into a captured nut, in the inside of the smaller rotator tube.
³ Mast ³
³ Pole ³
³ ³
³³Rotator³³
³³ Tube ³³
³³ ³³
³³ nut ³³ Mast
³ÃÄÄÄÄÄÄÄ´³ Hole
³³Wood ³³/
³³ [³==Bolt
³³ nut ³³
ÀÄÄÂÄÂÄÄÙ
/~~~~~~~³ ³~~~~~~~\ Water shed
³~~~~~Rotator~~~~~³ Cover
³ shaft ³
Why Don't U send an interesting Bul?
73 de John G8MNY @ GB7CIP
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