Message 28103 in TECH.WW
From: G8MNY
Date: Mon, 17 Aug 26 06:45:00 Z
Newsgroups: TECH.WW
Subject: Rotator 12V /P
Message-ID: <2472_GB7CIP>
Path: N2NOV|VA2RIZ|VK3AT|VK4OT|VK7AX|GB7CIP
R:260817/0646z @:N2NOV.#RICH.NY.USA.NOAM $:2472_GB7CIP
R:260817/0646Z 5350@VA2RIZ.#LAN.QC.CAN.NOAM LinBPQ6.0.25
R:260817/0646Z 31427@VK3AT.#MEL.VIC.AUS.OC LinBPQ6.0.24
R:260817/0645Z 2607@VK4OT.#NQ.QLD.AUS.AUNZ LinBPQ6.0.25
R:260817/0645Z 15835@VK7AX.#ULV.TAS.AUS.AUNZ LinBPQ6.0.24
R:260817/0645Z @:GB7CIP.#32.GBR.EURO #:2472 [Caterham Surrey GBR] $:2472_GB7CIP
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)
new at rally many years ago. Although the same hardware may not be available
other homebrew solutions may make this information useful.
=========
flat base plate
DIAGRAM
Non locking centre
off change over switch
plugs & sockets
MOTOR CONTROL
The simple circuit uses just a non locking change over switch to power the
under run low torque motor and 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
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 and 3 pot taps,
The pot is powered by a shunt regulated 9V supply. A large sensitive centre
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)
and the cal preset pot sets the full scale indication.
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
Physical calibration when portable is done by just lifting the rotator amd mast
turning whole thing and 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.
Why Don't U send an interesting Bul?
73 de John G8MNY @ GB7CIP
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