Sequoia Aircraft Corporation F.8L Falco, Construction Manual

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F.8L Falco Construction Manual 14–8 Revision 4, March 1, 2002
The antenna coupler may be installed either vertically or horizontally. The coupler may be
installed in several places. The most convenient place is inside the access door for the rudder
cable pulley.
Figure 2
See Drawing No. 410, Section A-A, for the installation of the antenna coupler. To install the
coupler at this location, it would be easiest to install it very early; however, the antenna coupler is
not sold separately from the Loran receiver. Since the coupler can be installed through the access
door, it can be installed after the airplane is completed, but you should run the antenna wire and
the coaxial cable during the construction of the Falco.
As previously stated, the antenna wire should run up the forward or aft face of the main fin beam.
Unlike the other antennas in the Falco the Loran antenna may be next to other pieces of metal,
and this does not affect its reception. We did inquire if it might make sense to use the upper
rudder hinges as part of the antenna by joining the antenna wire to the hinges. The answer was
that it would probably not help, and might well detract from, the reception. It does not matter if
the antenna wire is run around the hinges or up-and-over the ribs. You will find that you will
have to snake the antenna wire around things, and this does not affect the reception.
The coaxial cable from the antenna coupler should be run along the upper right side longeron to
frame No. 7, then to the center console area, then forward to frame No. 3 and up to the radio.
You will have to install BNC connectors at frame No. 8. In addition, you may want to install
BNC connectors below the instrument panel so that you can easily disconnect the antenna
coaxial cable for removal of the instrument panel.
You will notice that the top of the Loran antenna is close to the upper tip of the No. 1 COM
antenna. This is an unavoidable compromise, and it will cause an aft null in the COM antenna’s
pattern, but the null will be narrow (5 degrees or so) and so shallow (say, 15 dB) that it will not
materially affect the communication transceiver’s performance.
We did consider the possibility of installing the Loran antenna in the rudder, but this would put
the coupler in the rudder. It might be possible to locate the coupler in the leading edge of the
rudder, but we think this would be a difficult installation. Installing the coupler aft of the rudder
hinge line would be an invitation to flutter.