Hi Erich,
I am using the Ameri-King ELT also and spoke with Jim Thursby who was kind
enough to loan me pictures of his ELT setup. I copied parts of his and did
some things my way, as I'm sure you will too. Don't know if there is a
commonly used solution, it seems to be left up to the builders.
The ELT antenna is located just forward of the pitch containment structure
and a few inches toward port, clear of the rudder cable. (Most everything in
the back is located on the port side to allow me to lay on the stbd side
since I'm right handed -- if you're left handed you'll have to adjust
appropriately.) The antenna is mounted on a "U" of aluminum with little
flaps at the end to allow bonding. The height of the U allows the antenna
BNC plus a right angle BNC adapter (Radio Shack) to clear the fuselage.
Instead of a full ground plane, I used 4 copper strips 1/2 inch wide and the
suggested length as the ground; these are attached to the aluminum U with
6-32 screws. Two strips go forward and two aft, each pair forming a rough "V".
The antenna tilts to stbd based on the angle of the fuselage where it is
attached. The antenna can be bent slightly if necessary to clear the top of
the fuselage. Also, if it tends to rattle against things, drill a hole in the
pitch containment plywood and attach the upper end of the antenna to it with
a ty-wrap. Avoid conflict with the pitch bob weight, of course.
The TXP antenna ground plane is a 5.2 inch aluminum disk mounted just forward
of the ELT antenna, angled so it is horizontal when the fuselage is level.
This antenna is between the legs of the forward V for the ELT antenna - a bit
crowded in this area.
I mounted the ELT on the port side, well aft of the antenna, just forward of
the point where the fuselage seam angles upward toward the fin. It was
mounted here based on expected CG and may be moved in the future if necessary
- not flying yet, still painting.... In the Europa crashes so far, the rear
of the fuselage has separated just aft of the baggage bulkhead so this setup
may tend to keep the antenna and ELT together if the worst should happen.
(Of course, if the fuselage flexes a lot on impact the copper tape may break,
so adding a couple of regular wires as ground plane adjuncts could help.) A
small foam wedge was micro'ed in place under the ELT bracket prior to
glassing it in place, thus aligning the axis of the ELT with the aircraft.
Jim mounted his non-Ameri-King ELT just aft of the baggage bulkhead, between
the rudder cables - he is building an XS while mine is a classic, so he has
the battery in the back while mine is in the engine compartment. Different
ways to handle the CG for the two models. I assume I won't need to put the
battery in the back since I also have the original engine mount and cowl.
As a matter of philosophy, everything that pulses has its wiring on the port
side: transponder coax, strobes, trim. Comunication coax and wire to the ELT
are on the stbd side - the ELT wire passes across at the aft end to arrive at
the ELT. Conceptually, this should help to minimize noise pickup in the
radio. Time will tell.
Happy Building, John A044
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