Ramsey Electronics COM 3 User Manual

occur every 1 MHz throughout the range of the
Com 3, for example, 450.0000,451.0000,
452.0000, 453.0000 etc. This does not present
a problem however, as the level of the fourth
harmonic is only approximately 10 uv. An
incoming signal of 20-30 uv will easily over come
this. ሸ you have selected a frequency under
these conditions please be aware that the
squelch will open up and a weak carrier will be
heard. This should be of no concern and is
considered normal.
3.16 Leakage
Leakage from the Com 3 is virtually
unmeasurable.
If
you
are
using
the
Com
3
witha
coax cable connecting your transceiver to the
RF OUT jack, you will probably never have to be
concerned wiih leakage.Most mobile and base
tranceivers have plenty of shielding in their front
ends,
they
will
not
normally
receive
any
minute
radiated
emissions.
However,
in
the
event
that
you
are
making
a
sensitivity
measurement
ona
handheld
unit
or
a
pager
utilizing
a
direct
cable
connection,
shielding
caps
should
be
placed
on
all
unused
connectors
and
the
test
set-up
should
be
positioned
away
from
the
com
3.
Handheld
units
and
pagers
are
designed
to
pick
up
radiated
emissions
directly
through
antennas
mounted
either
on
them
or
in
them,thus
they
have
little
use
for
expensive
front
end
shielding.True
ㆍ
radiated
emission
—
(uv/cm")
testing
of
a
pager
or
a
handheld
tranceiver
can
only
be
accomplished
using
an
RF
shielded
test
box
.This
is
especially
true
in
RF
congested
areas.Keep
in
mind
that
all
generators
even
the
most
expensive
models
radiate
some
amount
of
RF
especially
at
UHF.
You
may
be
able
to
sniff
out
some
RF
from
your
(6010
using
a
handheld
“
Or
a
pager
but
this
is
normal.
RF
shielded
boxes
and
rooms
are
widely
available
although
expensive.
3.17 Audio Count Off Air
To
measure
audio
frequencies
off
the
air,
set
the
Com
3
up
for
receive
on
the
channel
frequency
desired,
then
touch
the
COUNT
AF
key.
Select
the
approximate
deviation
range
of
the
tone
by
touching
the
DEVIATION
key
(
ranges
are
+
1.5,
+
7.0
KHz).
High
deviation
tones,
21.5
KHz
or
greater,
should
be
read
in
while
in
the
+
7
KHz
range,
while
low
deviation
tones,
such
as
CTS,
in
the
+
1.5
KHz
range.
The
display
will
now
indicate
the
audio
frequency.
8.18 Audio Count External
Connect
the
audio
source
to
the
external
IN
jack,
then
touch
the
GENERATE
RF
key
and
the
COUNTAF
key
in
that
order.
The
external
light
will
automatically
come
on,
and
the
display
will
indicate
the
audio
frequency.
The
input
level
must
be
at
least
50
mv,
but
should
not
exceed
5
v.
3.19 RF Count
To
count
RF
frequencies
connect
the
whip
antenna
to
the
RF
IN
jack,
then
touch
the
COUNT
RF
key,
the
display
will
indicate
the
frequency
in
-
MHz.
The
range
is
10
MHz
to
999.999
MHz,
resolution is 1 KHz.
WARNING:
Do
not
transmit
into
the
RF
IN
jack,
this
will
cause
serious
damage
to
your
Com
3.
This
jack
is
for
whip
antenna
connections
only.
Transceivérs
should
be
connected
to
the
RF
OUT
jack,
inputs
over500
mW
will
be
switched
to
the
rear
panel
mounted
BNC
connector.

Ramsey Electronics COM 3 Specifications

General

Brand	Ramsey Electronics
Model	COM 3
Category	Monitor
Language	English