From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] ACK ELT trips with COM2 transmit
To: lml
Date: Thu, 13 May 2004 23:01:19 -0400
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Posted for "Dan & Kari Olsen" <olsen25@comcast.net>:

Scott and others,

  

A little more about my setup.

*	COM1 (UPS SL30) connected to Bob Archer SA-008 antenna in the
vertical tail
*	COM2 (UPS GX60 GPS/COM) connected to Bob Archer SA-006 antenna
on right side of fuselage behind baggage area bulkhead.
*	ACK E-01 ELT mounted on left side of fuselage behind baggage
bulkhead.  ELT antenna is copper foil antenna with torroids as per Bob
Nuckolls' AeroElectric Connection.  Antenna mounted on seatback
bulkhead.  ELT remote control in instrument panel and fed with the
supplied telephone wire.
*	No antenna splitters anywhere - each radio has its own dedicated
antenna
*	RG-400 coax everywhere

  

This afternoon I finally got through to the ACK technical support.  As
soon as he heard that I am using the Bob Archer antennas he immediately
focused all blame on them.  I have a EE background but am no RF guy -
however, I think the only thing to blame with the Bob Archer antennas is
that they are very efficient (I measured VSWR of <1.3)  and I think the
ACK ELT does not have appropriate filtering to be able to withstand any
significant RF energy in the area.  The COM is probably radiating a very
good percentage of its energy and my ELT antenna is picking up a very
good bit of it and the ELT cannot handle it.  I'm also quite suspect of
the unshielded phone cord that is run to the remote control panel.  Have
any of you addressed this?  Ferrite beads?  Shielding?

When I told the support guy that I had searched the LML archives and
learned that ACK has modified the remote control for some Lancair
builders to solve the problem he immediately went back to the Bob Archer
antennas and was not interested at all in any mods to help me with his
deficient product.  His suggestion is to tear out the Bob Archer
antennas from the COMs and replace them with external Comant antennas
with 36" ground planes as well as the Nuckolls ELT antenna and replace
it with a whip antenna and ground plane.   Frankly, if I am going to
tear anything out it will be the ELT and replace it with an AmeriKing or
other brand that will actually work!

Any wisdom from you RF guys would be appreciated.

Thanks!

Dan