Mailing List lml@lancaironline.net Message #2084
From: Brock Brinkerhoff <brockbr@mindspring.com>
Subject: LC20 - COM Antenna Location VHF-5T
Date: Mon, 22 Mar 1999 16:38:28 -0600
To: <lancair.list@olsusa.com>
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Ok - I'll quit lurking and ask the question I've had for some time now.



I have a 235 with an O-290-D2.  It had an antenna mounted in the aft

fuse, but every time I keyed the mic I would get tons of interference on

all of the electrical engine gauges  (tach would peg, oil temp would

read 30 higher and so on.)  I removed the antenna from the fuse, and by

accident found out that if I attached a wire, about 24 inches long to

the antenna's ground plane (which after the fact I learned was MISERABLY

too small), it worked fine, and without interference - but - It would

only work this way if the wire was pulled back towards to panel (I know

this sounds crazy, but it's true).



So, I shopped around for an antenna and found one that Aircraft Spruce

has in their catalogue (VHF-5T).  It is meant to be placed inside the

aft fuse, mounted flat.  The antenna itself resembles a strip of

fiberglass about 1 inch wide by 30 inches.  The nice thing about it was

that it did not require a ground plane, but (little did I know) it

needed to be mounted as close to vertical (or a max of 45 degrees from

vertical) to be most effective.  Of course (using hindsight) using the

vertical positioning makes sense, but since the airplane is already

complete, I cannot think of a single place to stick this antenna to get

the required mounting position for it to be effective.



Now, I'm not completely stuck with mounting this antenna, as I would

take anything that worked right and did not cause RF interference with

the gauges.



Any suggestions?



Brock Brinkerhoff

290DM
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