[TowerTalk] ATAS-120

N6KI Dennis Vernacchia n6ki_73 at sbcglobal.net
Mon Feb 5 02:31:34 EST 2007


    First test it manually by applying a Positive voltage to the center 
pin in the antenna base
and the Negative voltage to the thread area ( I screw an SO-239 barrel into
the base of the antenna and then screw on a length of coax that has a 
on one end and the other end you apply the voltage to..

I forget the exact voltages but using a variable supply at some voltage 
over 5 Volts
the antenna normally retracts and at some voltage above 8 or 9 Volts the 
antenna extends
( or vice versa )

DO NOT REVERSE POLARITY TO THE ANTENNA - Always apply a Positive voltage
ONLY  to the center pin or you can blow up the internal circuit !

Anyway, if when manually applying a voltage it extends and retracts
you have a control problem with the rig

If you hear the motor running and antenna  neither extends or retracts,
you may have sheared a small plastic part inside the antenna
while tuning it at High Speeds.
( The plastic part is in the upper part of the antenna )

The ATAS-100 was notorius for snapping that $16 internal plastic piece 
when extending
or retracting the antenna  from 20 to 30 or 40 meters and vice versa 
when driving
at speeds greater than 60 mph
The longer the antenna  extended the more strain it put on that plastic 

I though that that problem was solved with the more rigid design of the 
ATAS-120 but maybe

I have some exploded view drawings I can send you if you think you broke 
the small
plastic internal part and want to replace it yourself. It is not very 
difficult if you
are careful and handy with tools and watch how things come apart.

As I recall when I repaired a friends ATAS-100 to replace that plastic 
part, there were some
small ball bearings inside you want to be careful you don't lose.

73, Dennis N6KI

Bmennell wrote:
> My ATAS-120 Antenna on my truck just stopped working it does not go up or
> down on Tune or Manual.   Rig is the FT-857D.  Have not used it very much at
> all.  I hear it working but is not going anywhere.  Everything still kinda
> new.  Any suggestion on what is wrong.  Thanks,
> Bob Mennell
> Lorne International
> 406 Westwood North Drive
> Magnolia,  Texas 77354
> 936-321-8649 Office
> 936-321-6946 Fax
> bmennell at houston.rr.com
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