
CHAPTER
7
ANTENNA
SETUPS
Revised: 15 Feb 2017
7-1
ESTeem Models 195MHC
ESTeem
offers
different
types
of
antennas
ranging
from
¼
wave
to
5/8
wave
in
physical
size.
The
user
choice
is
dependent
on
the
application.
Communications
in
the
VHF
and
UHF
bands
are
normally
over
"Line
of
Sight
(LOS)"
.
Looking
from
the
antenna
of
one
wireless
modem
you
must
be
able
to
see
the
antenna
of
the
wireless
modem
you
wish
to
communicate
with.
If
a
large
object
obstructs
the
line
of
sight
view
it
is
unlikely
that
satisfactory
communications
will
result.
This
means
you
must
relocate
the
antennas
or
use
the
repeating
freature
and
a
second
modem
to
go
over
or
around
the
object.
The
Model
195C,
195M
and
195H
products
are
allowed
by
the
FCC
to
use
high
gain
directional
antennas.
It
is
noted
that
a
¼
wave
antenna
that
does
not
have
ground
plane
radials
requires
a
ground
plane
to
operate
at
maximum
efficiency.
This
can
simply
be
a
conducting
surface
under
the
antenna
that
is
a
¼
wavelength
in
diameter.
For
the
Model
195C
(450
‐
470
MHz)
this
is
approximately
6.5
inches.
A
conducting
surface
can
be
anything
from
the
rooftop
of
an
automobile
to
a
file
cabinet.
Coax
Cables
To
minimize
signal
loss,
the
overall
length
of
the
coaxial
cable
should
be
as
short
as
possible.
To
avoid
corrosion
select
coaxial
cable
manufacturers
with
tinned
copper
braid,
where
possible.
Listed
below
are
representative
cable
losses
in
db/100ft
at
the
VHF
and
UHF
frequencies:
Frequency
(MHz)
RG
‐
58u
LMR
195
RG
‐
8
(solid)
LMR600
1/2"
Heliax
150
‐
174
‐
3.8
‐
4.4
‐
1.2
‐
0.964
‐
0.88
217
‐
220
‐
5.4
‐
5.4
‐
1.7
‐
1.4
‐
0.95
402
‐
420
‐
7.9
‐
7.8
‐
2.4
‐
1.72
‐
1.36
450
‐
470
‐
9
‐
7.8
‐
3
‐
1.72
‐
1.45
In
a
severe
noise
environment
it
may
be
desirable
to
use
a
double
shield
type
of
coax
cable
such
as
RG
‐
214/U.
Note:
Pre
‐
made
coax
cables
can
be
purchased
from
the
factory.
A
‐
3
dB
loss
means
you
have
lost
1/2
of
your
signal.
A
+3
dB
gain
means
you
have
doubled
(x2)
your
signal.
Keep
the
antenna
feedline
as
short
as
possible
to
minimize
losses.
Extreme
care
must
be
taken
when
attaching
coax
connectors
to
the
antenna
feedlines.
If
there
is
any
error
in
making
this
connection
the
output
of
the
transmitter
will
be
greatly
reduced.
Summary of Contents for 195C
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