[TowerTalk] Parts for AEA Isoloop

[Eric Gustafson]

>From: "Dennis Utley" <AF7Y@msn.com>
>Date: Sun, 9 Aug 1998 15:43:20 -0700
>
>I believe AEA is out of business.
>
>Does anyone know if someone is selling parts for the AEA Isoloop
>10-30?
>
>I haven't used mine in two years, but recently opened it up to
>check on its condition.  I found a broken part that connects the
>stepper motor worm drive to the large capacitor. (gear and
>plastic insert that goes inside the large capacitor)
>
>Any suggestions would be appreciated
>
>Dennis Utley, AF7Y


Dennis,

If you find a source for this part, please post it here on the
reflector.  I have been involved in troubleshooting problems with
5 of these loops now here in the Tucson area.  All of the
problems were ultimately traced to a failure of the part you
describe.  Fortunately, this all happened while we could still
get replacements from AEA.

This part is obviously underdesigned for its intended
application.  Of the 5 loops we repaired here, 2 failed to
survive shipping.  They didn't work when tested on the ground
right out of the box.  One more didn't survive installation
(worked on the ground but not once up in the air).  The other two
failed during relocation.  We are pretty sure that these loops
were bumped from the side during handling as a part of the
relocation process.  We know for sure that one of them was
temporarily placed on the roof in the vertical orientation.  The
owner lost his hold of the top of it and it tipped over about 12
inches until it hit the chimney that it was next to.  This was
not a tremendous shock.  But it was in exactly the wrong plane
for stressing this part.


Anyone owning one of these antennas: 

Be EXTREMELY careful to prevent shocks from being delivered to
the loop case from a direction perpendicular to the plane of the
loop.  In fact, handle the thing like it was an expensive piece
of crystal or china.  The plastic coupling that connects the
stepper motor to the capacitor rotor (a fairly massive assembly)
is the only source of mechanical support for the motor end of the
rotor.  This piece of plastic is not designed to be able to
withstand the loads it is exposed to when the antenna is
subjected to any sudden acceleration.  Even normal shipping and
handling stresses are sufficient to cause failure of this part.
The first sign of failure (prior to complete failure) is
excessive (and increasing) backlash in the tuning mechanism.

73, Eric  N7CL

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