Heavy
Duty
Feed
Strut
________________________
We
have
developed
a
new
feed
strut
and
collar
for
the
heavier
4
Port
Seavey
feed
assembly.
This
utilizes
the
rectangular
aluminum
tube
for
the
feed
strut.
Figure
#12
right
shows
the
sketch
of
this
feed
assembly;
it
is
very
simple
to
install.
Each
strut
has
2
‐
5/16
x
2
1/4”
bolts
to
attach
to
the
feed
collar.
Now
attach
one
of
the
angle
brackets
(2"
x
2")
to
the
antenna
with
the
1/2"
x
3"
bolts.
Notice
that
angle
bracket
has
two
holes.
You
will
use
the
bottom
hole.
The
top
hole
is
for
an
optional
Chaparral
type
feed.
Next,
attach
the
base
of
the
strut
to
the
angle
brackets
with
the
5/16
x
1
1/2"
bolts
supplied.
Align
the
feed
to
point
directly
at
the
center
of
the
antenna.
Now
measure
the
focal
length
to
the
front
of
the
scalar
rings.
(
Seavey
recommends
f/l
is
measured
to
front
of
scalar
ring.
)
Ku
Band
Feed
Assembly
-----------------------------
When
using
the
Ku
only
feeds,
you
will
be
using
the
C14F
feed
plate
and
tri
‐
collar.
See
Figure
#13.
First,
attach
the
flat
tri
‐
collar
to
the
feedhorn
as
follows:
attach
the
first
two
pieces
by
using
the
8
‐
32
x
1"
screws
provided.
Now
slide
the
collar
onto
the
feedhorn
and
add
the
third
piece;
tighten
evenly.
Attach
the
tri
‐
collar
to
the
larger
horseshoe
collar
by
the
8
‐
32
x
¾”
bolts
and
nuts;
tighten
down.
You
can
adjust
polarity
by
loosening
these
nuts
and
rotating
feed.
Finish
by
assembling
the
struts
to
the
feed
collar
as
shown
in
Figure
14.
(Fig#14
shows
single
Ku
feed
inserted
in
collar)
Figure
#13
Figure
#14
Fine
Tuning
the
Antenna
--------------------------------
After
the
assembly
is
complete,
we
recommend
you
"string
the
antenna."
Simply
run
a
string
from
a
back
brace
across
the
front
of
the
antenna
to
the
brace
180
degrees
apart.
Now
do
this
with
each
brace.
If
the
strings
all
meet
in
the
middle
and
no
pressure
is
on
any
of
them,
the
antenna
is
perfect
and
no
further
work
needs
be
done.
If
one
of
the
strings
is
not
close
to
the
others,
then
step
back
and
sight
across
the
dish
and
see
where
you
will
have
to
push
with
the
back
braces.
Only
make
small
adjustments
at
a
time
and
remember
to
start
with
all
braces
loose.
After
you
are
sure
the
antenna
surface
is
flat,
you
should
double
check
to
see
that
the
feedhorn
is
set
at
the
proper
distance,
then
check
to
see
that
it
is
pointed
at
the
center
of
the
antenna.
In
our
years
of
setting
up
antennas,
these
three
items
seem
to
cover
over
98%
of
all
problems
of
picture
quality.
PAGE
11
Feed
Strut
Length
2.4m
&
2.7m
with
a
39”
mount
is
36
5/8”
3.0m
with
a
48”
mount
is
41
3/4”
Figure
#12
½” x 3” Bolts
