TFT 886 EBS System User manual
www.SteamPoweredRadio.Com
PIN
5004--0886
Revision B
September 7, 1990
Equipment Serial No.
__
_
Shipment
Date
____
_
OPERATION
MANUAL
MODEL
8.
86
AM EBS SYSTEM
MODEL
887
FM
EBS SYSTEM
TFT, Inc.
3D90
Oak.mead Village Drive
P.O. Box 58088
Santa
Clara,
CA
95052-8088
TEL: (408) 727-7272
FAX: (408) 727-5942
www.SteamPoweredRadio.Com
P/NSOOS-
0886/0887
Rev.~
Revision
Date
JUNE
1991
Effectivity
SIN
1100450
TFT
OPERATION
MANUAL
ADDENDUM
MODEL
886/887
MANUAL
P/N
5004·
0886/0887
Rev.
B
IMPORTANT
MANUAL
CHANGES
1.
AH LOOP ANTENNA FOR MODEL
886
EBS AM
RECEIVER
A
tuneable
loop
antenna
for
AM
reception
has
been
tested
by
TFT
and
found
to
be
an
effective
device
for
use
in
conjunction
with
the
TFT
Model
886,
EBS
AM
Receiver.
This
loop
antenna
is
used
indoors
to
optimized
RF
gain
and
selectivity
.
This
antenna
is
also
available
through:
Edmund
Scientific
101
E.
Gloucester
Pike
Barrington,
NJ
08007-1380
(609)
573-6250
Trade
Name:
Super
Select-a-tenna
Part
No. 72147
If
higher
RF
signal
level
to
the
Model
886
is
required
an
outdoor
antenna
can
be
used
.
See
the
diagram
below
for
installation
and
connections.
3
F'T
OR
HIGHER
•
SENSITIVITY
CAN
BE
INCREASa>
BY
USING
A
LONG
w'lRE
ANTENNA
CONNECTED
IN
THE
Fll..l.Dw'ING
MANNER,
SELECT-A-TENNA
CUT
OFT
OUTER
CONDUCTOR
6'
COAXIAL
CAIL£
FROM
TI£
F'
ACTDRY
TF'T
PIN
4750-0827
CENTER
CONDUCTOR
UlNG
w'lRE
ANTENNA
OUTSIDE BUILDING
TFT
MODEL
886
2.
Model
887
FM
Antenna
Installation
a.
Replace
page
2 .5
b.
Add
Fig.
2.3
after
Fig.
2 . 2
TFf
Form No.
S300-01.68C
2-26-90
www.SteamPoweredRadio.Com
AM
and
FM
EBS Systems
h.
For
remote control usage, connect the
REMOTE
ACTIVATION
(ON
AIR
)
terminals, pins 8 (ground) and 9
of
J3
on
the 887
rear
panel, and the
REMOTE
RESET
terminals, pins
10
(ground) and 11
of
13
, to momentary-
to-ground switches. Grounding these lines activates the functions.
1.
If
the
887 will
be
used to activate a station alarm, connect the alarm device
to
the
EBS ALARM RELAY terminals, pins 1 thru 6
of
J1
on the 887
rear
panel. See Figure 2-1, Model 886/887 Wiring Diagram,
at
the back
of
this
section for relay configuration.
j.
Ac power is applied through the
rear
panel ac connector. Connect the line
cord
to
an
appropriate outlet.
The
887 should now
be
on.
2.6 AM Antenna Installation
If
a local AM antenna is not available,
an
end-fed long wire antenna (approximately 250
ft.) can
be
used.
One
end
of
the long wire should
be
connected to
the
ANT
75Q
connec-
tor
.
For
moderately strong signal areas,
an
alternative
to
the long-wire antenna connection
can
be
used. Refer
to
Figure 2-2, AM Antenna Installation Diagram,
at
the back
of
this
section.
2.
7
FM
Antenna Installation
For
indoor and moderate strong
area
,
the
supplied
FM
indoor antenna and 300Q to
75Q
matching transformer can
be
used. Refer to Figure 2-3
FM
antenna matching installation
diagram
at
the
back
of
this section for connection.
2-5
www.SteamPoweredRadio.Com
SECTION!
1.1
1.2
1.3
1.4
SECTION 2
2.1
2.2
2.3
2.4
2.5
2.6
Figure 2-1
Figure 2-2
SECTION 3
3.1
3.2
3.3
3.4
Figure 3-1
Figure 3-2
SECTION 4
4.1
4.2
Model 886
AM
EBS System
Model 887 FM EBS System
Table
of
Contents
Page
GENERAL INFORMATION
General
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Spec1f1cat1ons . .
..
.
...........
...
.........................
..
1-2
Warranty
..................
...
...
...
....
...
.
............
...
. 1-5
Claim
for
Damage
in
Shipment
..............
.
...............
1-6
INSTALLATION
Unpacking
and
Inspection
........................
.
....
....
..
2-1
Power
Requirements
............
'.
........................
...
2-1
Pre-installation
DIP
Switch Settings
....
.
..................
.
..
2-2
AM
System Installation
....
. .
..
.....
.
...
.
......
.
............
2-3
FM
System Installation
......................................
2-4
AM
Antenna
Installation
......
.
............
..
...
..
..........
2-5
886/887 Wiring Diagram
AM
Antenna
Installation Diagram
OPERATION
6600-2608
6600-2601
General
Discussion
.....
...
.....................
....
..
.
.....
3-1
Turn-on
and
Warm-up
.................
.
........
. . .
.........
3-1
Controls, Connectors,
and
Indicators .....
.........
.....
......
3-2
System
Operation
....................................
.
...
..
.
3-8
3.4.1
Operation
of
the
AM
Receiver
..
.
..
. . . .
....
..
.
..
.
.....
3-8
3.4.2
Operation
of
the
FM
Receiver
............
..
...........
3-9
3.4.3
Operation
of
the
Two-tone
Generator
(AM
and
FM)
...
. 3-9
Model 886
Front
and
Rear
View Illustration
Model 887
Front
and
Rear
View Illustration
THEORY
OF
OPERATION
6600-2598
6600-2599
General
Discussion (Block Diagram, Figure 6-1)
..
.
...........
4-1
Main
Board
(Figure 6-2)
.......................
. . .
..........
4-4
4.2.1
Tone
Generation
.............................
..
....
. . 4-4
4.2.2 Controls
and
Indicators . .
......
.
....
.
.......
. .
..
...
.
..
4-6
4.2.3
Calendar
Displays
......
.....
..
.....
...
.
.....
.
....
.
...
4-8
4.2.4
Power
Supply Voltages .
..
. . . .
..
...
. .
.......
.
..
..
.
..
...
4-9
11
www.SteamPoweredRadio.Com
AM
and
FM
EBS Systems
4.3
4.4
4.5
SECTION 5
5.1
5.2
5.3
5.4
5.5
5.6
5.7
SECTION 6
Figure No.
6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
6-10
6-
11
Display
Board
(Figure 6-4)
.....
..
.
.....
...
..
................
4-9
AM
Receiver
Board
(Figure
6-6) .
..........
....
. . .
....
...
.
...
4-10
FM
Receiver
Board
(Figure 6-8)
....
.
......
.
...
.
........
..
...
4-11
MAINTENANCE
Periodic Maintenance . .
..
......
...
. .
..
. . .
...
.........
.......
5-1
AM
Receiver Performance Checks
......
...
.....
..........
...
5-1
5.2.1
AM
Receiver Sensitivity
...
........
.
...
.
.......
.....
..
. 5-1
5.2.2
AM
Receiver
AGC
Range
. .
......................
.....
5-2
FM
Receiver Performance Checks .
...
........
.
..
.
......
......
5-2
5.3.1
FM
Receiver Sensitivity .
..
....
...
..
. .
..
. .
....
. . . . .
...
. 5-2
5.3.2
FM
Receiver
AGC
Range
.....
.......
.
...........
...
. . 5-3
Dual-tone
Level Adjust
(AM
and
FM)
....
..
...
.
...
...
..
......
5-3
Calendar
Display Adjust
(AM
and
FM)
...
.
.........
.........
. 5-4
Receiver
Audio
Output
Adjust
..
.
......
,
..
.....
...
....
..
....
. 5-4
5.6.1
AM
Receiver
Audio
Output
Adjust .
..
...
.
...
.....
......
5-4
5.6.2
FM
Receiver
Audio
Output
Adjust
...
....
.........
.....
5-5
Receiver
Audio
Signal versus
Dual-tone
Signal
(AM
and
FM)
.
......
.
...
......
..
......
...
.....
.
...
....
...
. . 5-5
DIAGRAMS AND SCHEMATICS
Title
EBS
Block Diagram
Main
Board, Schematic
Main
Board,
PCB
Assy.
Display Board, Schematic
Display
Board
, PCB Assy.
AM
Receiver Board, Schematic
AM
Receiver Board,
PCB
Assy.
FM
Receiver Board, Schematic
FM
Receiver Board, PCB Assy.
Compo
s
ite
Loop
Thru
Board
, Schematic
Composite
Loop
Thru
Board, PCB Assy.
iii
Drawing No.
6600-2591
6601-3638
6608-3638
6601-3636
6608-3636
6601-3635
6608-3635
6601-3637
6608-3637
6601-3734
6608-3734
www.SteamPoweredRadio.Com
SECTION 1
GENERAL INFORMATION
1.1 General Description
AM
and
FM
EBS Systems
The
Models 886
and
887 EBS Systems are designed for broadcasters to
meet
Parts 73.940,
73.941, and 73.942
of
the FCC Rules and Regulations.
The
886 AM Receiver uses a frequency-synthesized local oscillator which is phase-locked
to
a 5
MHz
crystal oscillator.
It
is tunable across the AM broadcast
band
in
10
kHz
increments via a 3-digit front panel pushbutton switch.
The
886 Receiver's stability is
±500
Hz
per
year.
In
addition to broadcast station use,
the
AM
Receiver provides low cost EBS monitoring
for emergency services such as police, fire, hospitals,
and
Civil Defense agencies listening
to
EBS-participating stations during
an
emergency.
The
887
FM
Receiver is a high performance, tunable receiver.
It
uses a 3-digit front
panel pushbutton switch
that
tunes
in
100
kHz
increments. This receiver is ideally suited
to
FM
inter-city relay networks, key links
in
the EBS alerting procedure, thus allowing
pickup
and
rebroadcast
of
emergency programming without degradation
of
signal quality.
Both EBS Systems have a built-in, two-tone decoder for the 853
Hz
and
960
Hz
EBS
signaling tones from demodulated outputs. Stable piezoelectric tuning fork filters are
used
to
achieve a bandwidth
of
±5
Hz
from each tone frequency.
This integral two-tone EBS generator, which uses individual crystal oscillators, produces
the
853
Hz
and
960
Hz
tones
simultaneously, with
an
accuracy
of
±0.25 Hz.
Tone
amplitudes may
be
observed
and
adjusted individually.
Test
and on-air transmission
switches
are
provided
on
the front panel.
There
are two 2-digit
LED
displ
ays
on
the
front panel
of
both
systems.
These
displays
show the
number
of
days
(up
to
12) since EBS
test
transmissions were last received
and/or sent. Two
LED
bar
graph displays are also provided for audio
and
RF
level obser-
vations.
A speaker is provided
on
the front panel for audio monitoring. This speaker works in
conjunction with
the
rear panel volume control, which also adjusts the volume
of
an
exter-
nal speakerwhen connected to a
rear
panel phone jack.
Both receivers are configured
at
the
factory
to
operate from a 117 Vac, 50
Hz
or
60
Hz
power source.
1-1
www.SteamPoweredRadio.Com
AM
and
FM
EBSSystems
1.2 Specifications
AM Receiver
Frequency
Range
.........................................
540
kHz
to
1750
kHz
Local
Oscillator
Stability............................
±500
Hz
per
year
Tuning Method.............................................
Pushbutton
stepswitch
in
10
kHz
incre-
ments
Antenna
Input...............................................
750
nominal,
unbalanced
Sens1t1v1ty.......................................................
30
µ V
for
20
dB
signal-to-noise
at
30%
modulation
Image
Rejection
........................................... 25
dB
AGC
.................................................
..
.............
60
dB
IF
Bandwidth, 6 dB......................................
±5
kHz
Harmonic
Distortion...................................
Less
than
3%
at
75%
modulation
Noise............................................................... 45
dB
or
greater
below
75%
modulation
with
10
mV
/meter
RF
signal level
Audio
Outputs
(6000).................................
Balanced:
+
8
dBm
Unbalanced:
1
Vrms
Carrier-off
Output........................................ Active
pull-up
to
10 V, 10
mA
FM Receiver
Frequency
Range......................................... 88
MHz
to
108
MHz
Tuning
Method.............................................
Pushbutton
stepswitch
in
100
kHz
incre-
ments
Antenna
Input...............................................
750
nominal,
unbalanced
1-2
www.SteamPoweredRadio.Com
AM
and
FM
EBS
Systems
Sens1t1v1ty........................................................ 2 µV
for
20
dB
quieting
IF
Bandwidth, 6 dB.......
...
............................ ± 150 kHz
Image Rejection............................................
40
dB
AGC................................................................. 80
dB
Audio Frequency
Response...............
...
....................................... ± 1 dB,
50
Hz
to
15 kHz
Harmonic
Distortion.................................... 1%
at
33%
modulation
Signal-to-noise
Ratio
(SNR)..............................................................
60
dB
or
greater below 100% modulation
at
50
1-i
V
RF
input
De-emphasis.................................................. 75 ,,sec
Audio Outputs
(6000)
................................. Balanced:
+8
dBm
Unbalanced: 1 Vrms
Carrier-off
Output
........................................ Active pull-up to 10 V, 10
mA
Decoder (AM and FM)
Decoder
Input
Level.................................... 100 mV into
6000
Bandwidth.......................................................
:t:5
Hz
Frequency Stability.......................................
±0
.25 Hz, crystal-controlled
Audio
Output
Level..................................... 250 mW, internal speaker
Generator
Output
Level
(
6000)
....................................................
...
....... Balanced: +8 dBm
Unbalanced:
1
Vrms
1-3
www.SteamPoweredRadio.Com
AM
and
FM
EBS Systems
Harmonic Distortion.......................
....
...
..
.
..
Less than
2%
Tone Duration
..
.
....
........................
..
.
..
...
...
.
...
6, 12, or
24
seconds, adjustable
Tone Level Adjust......................................
..
Internal
Time Delay for De-muting......................... Adjustable
to
2,
4,
or
8 seconds
External Alarm Contacts......................
......
SPDT relay contacts
to
rear panel strip
Front Panel
Day Display ............................
.....
.................. Two 12-day digital displays
to
record num-
ber
of days since last transmission and/or
reception
of
two-tone transmission. Auto-
matic reset.
ON/STANDBY Switch...........
....
...
..
............ 3-position, spring-loaded toggle switch.
In
the
ON
mode, the speaker is demuted. In
the STAND
BY
mode, the speaker is
muted until
an
EBS alert
is
received.
RESET Switch.......................
..
........
..
........... Resets (mutes) the speaker after receipt
of
BBS transmission.
TEST/RESET Switch.........
....
..................... 3-position, spring-loaded toggle switch. In
the TEST
po
sition, the 886/887 performs a
self-test
of
the decoder.
In
the RESET
position,
it
interrupts on-air transmission
or
a self-tes
t.
ON
AIR Switches..................
..
...........
..
........ Two 3-position, spring-loaded toggle
switches. Must be held in opposing posi-
tions. Used
to
prevent accidental test
transmission.
853 Hz/960
Hz
OPERATE Switch.......
..
....
.......................... 3-position, spring-loaded toggle switch.
Tests individual tones and connects both
tones
to
an
output for test operations.
1-4
www.SteamPoweredRadio.Com
AM andFM
EBS
Systems
Mechanical
and
Environmental
Receiver
Input
Power........................
..
........ 117
Vac
, ± 15%,
50
Hz
or
60 Hz, 20 W
maximum
Operating
Temperature
..............................
0°C
to
+
50°C
(32°F
to
122°
F)
Dimensions.............
...
..
................................... 1 3/4" (4.4 cm) H x 19" (48.3 cm) W x 10"
(25.4 cm) D
Weight............................................................. 6
lbs
.
(2
.7 kg)
1.3 Warranty
TFT,
Inc., warrants each
of
its manufactured instruments
to
meet
the
specifications
when
delivered
to
the
BUYER
and
to
be
free
from
defects
in
material
and
workmanship.
TFT
will
repair
or
replace,
at
its expense,
for
a
period
of
one
year
from
the
date
of
delivery
of
equipment, all
parts
which
are
defective
from
faulty material
or
poor
workmanship.
Instruments found
to
be
defective during
the
warranty
period
shall
be
returned
to
the
factory with transportation charges
prepaid
by
the
BUYER.
It
is expressly
agreed
that
replacement
and
repair
shall
be
the
sole remedy
of
BUYER with
respect
to
any non-con-
forming
equipment
and
parts
thereof
,
and
shall
be
in
lieu
of
any
other
remedy available
by applicable law. All returns
to
the
factory
must
be
authorized
by
the
SELLER
prior
to
such returns.
Upon
examination by
the
factory, if any
instrument
is
found
to
be
defective,
the
unit
will
be
repaired
and
returned
to
the
BUYER, with transportation charges
prepaid
by
the
SELLER.
Transportation charges
for
instruments found
to
be
defective within
the
first
30
days
of
the
warranty
period
will
be
paid
both
ways by
the
SELLER.
Transportation
charges
for
warranty
returns
wherein
failure is found
not
to
be
the
fault
of
the
SELLER
shall be paid both
ways
by
the
BUYER.
NO
OTHER
WARRANTY
IS
EXPRESSED
OR
IMPLIED
.
TFT
IS
NOT
LIABLE
FOR
CONSEQUENTIAL
DAMAGES.
1-5
www.SteamPoweredRadio.Com
AM
and
FM
EBSSystems
1.4 Claim for Damage in Shipment
Your instrument should be inspected and tested
as
soon as
it
is
received. The instrument
is insured for safe delivery.
If
the instrument is damaged in any way
or
fails to operate
properly
due
to
transportation
damage, file a claim with
the
carrier
or, if insured
separately, with the insurance company.
WE SINCERELY PLEDGE
OUR
IMMEDIATE AND FULLEST COOPERATION
TO
ALLUSERS
OF
OUR
PRECISION ELECTRONIC INSTRUMENTS.
PLEASE ADVISE
US
IF
WE CAN ASSIST
YOU
IN ANY MANNER.
TFT, Inc.
3090 Oakmead Village Drive
P.O. Box 58088
Santa Clara, CA 95052-8088
(408) 727-7272
TWX
910-338-0584
FAX
(408) 727-5942
1-6
www.SteamPoweredRadio.Com
SECTION 2
INSTALLATION
2.1 Unpacking and Inspection
AM
and
FM
EBS
Systems
Upon receiving the instrument, inspect the packing box and instrument for signs
of
pos-
sible shipping damage. After installation, operate
the
instrument in accordance with
the
procedures in Part A, Section 3, Operation,
of
this manual.
If
the instrument is damaged
or
fails
to
operate properly due
to
transportation damage, file a claim with the transporta-
tion company or, if insured separately, with
the
insurance company.
2.2 Power Requirements
Both AM and FM EBS Systems are factory-wired
to
operate from 117 Vac. The line
frequency must be either 50
Hz
or
60 Hz.
To
select either 50
Hz
or
60 Hz, jumpers
(supplied) must
be
placed at the appropriate pins at both
Pl
and P2
on
the
Main Board.
For
50
Hz
, pins 3 and 4 must
be
jumpered; for 60
Hz
, pins 1 and 2 must
be
jumpered.
Refer to
the
exploded view
of
Pl
and P2 below for pin locations. Maximum power re-
quired is 20 watts.
Tl
Pl
POWER
TRANSFORMER
°'
:::
en
..,
tli
·~·
"'
Q.
-
'r
r21ooool
4 3 2 1
SWlO
IU1f
11
EBS Main Board
Front Panel
Model 886/887
Note
:
Pin
1
of
Pl
and
P2
is
the
squared
hole
.
From
the
front
panel
view
,
the
pins
are
numbered 1-4 from right to left.
2-1
www.SteamPoweredRadio.Com
AM
and
FM
EBS
Systems
2.3 Pre-installation DIP Switch Settings
There are
two
DIP
switches located on the Main Board. They can be used to set the
duration for the dual-tone signal and to set the
de
-muting time delay. These switches
are
shown
in
the figure for Paragraph 2.2 above.
SW9 is used
to
set the
tone
duration for the dual-tone signal for either
6,
12,
or
24
seconds. This switch is
set
for 24 seconds at the factory.
SWlO is used
to
set
the time delay for the de-muting circuit. It can
be
set for either 2, 4,
or 8 seconds. SWlO is set for 8 seconds
at
the factory .
To
change these DIP switches for
other
than
the
times
set
at
the factory, perform the
following:
a. Remove the EBS top cover.
b.
To
change the dual-tone duration, depress the switch position
on
SW9 for
the desired time according to
the
following list.
The
remaining switch posi-
tions should
be
in the OPEN position.
Position 2 = 6 seconds
Position 3 = 12 seconds
Position 4 =
24
seconds
Position 1 = Unused and should be
in
the OPEN position
c.
To
change the time delay, depress the switch position
on
SWlO for the
desired time according to the following list.
The
remaining switch positions
should
be
in
the
OPEN position.
Posron
2 = 2 seconds
Position 3 = 4 seconds
Position 4 = 8 seconds
Position 1 = Unused and should be
in
the
OPEN position
d. Replace the EBS top cover and continue with the installation procedure
below.
2-2
www.SteamPoweredRadio.Com
AM
and
FM
EBSSystems
2.4 AM System Installation
The
Model 886 is calibrated and ready for installation into an equipment rack for imme-
diate use. Ensure proper environmental conditions exist as specified
in
Section
1,
Para-
graph 1.2
of
this manual.
The
operating temperature for this unit is between 0°C and
50°C (32°F and 122°F).
To
install the 886, perform the following:
a. Mount the Model
886
in
the equipment rack and secure.
b.
If
an
AM receiver is installed, connect a
75Q
coaxial cable from the antenna
to
the ANT
75Q
connector on the rear panel
of
the 886. Ifa
75Q
coaxial
cable
is
unavailable, an alternative antenna can
be
used. See Paragraph 2.6
below for further installationinstructions.
c.
If
desired, the
RX
AUDIO UNBALANCED terminals, pins 9 (ground) and
10 of
J1
on
the rear panel
of
the 886, can
be
connected
to
a monitor
or
other external device.
d.
The
RX
AUDIO BALANCED terminals at
Jl
, pins
11
and 12
on
the rear
panel
of
the 886, can
be
connected to a monitor
or
other external device.
The
output
at
these terminals is +8 dBm into
600Q
.
e.
If
a remote indication ofcarrier failure is
to
be
provided, connect the CAR-
RIER
FAIL terminals, pins 7 (ground) and 8
of
Jl
on
the rear panel
of
the
886,
to
the remote indicator.
The
output 10
Vat
10
mA
for carrier loss.
f. Connect the program output
to
the AUDIO LOOP
THRU
RIGHT
CH
BALANCED INPUT terminals, pins 4 and 5
of
J2
on
the 886 rear panel.
Connect the monaural program output line
to
the AUDIO LOOP
THRU
RIGHT
CH
BALANCED OUTPUT terminals, pins 1 and 2
of
J2
on
the
886 rear panel.
g.
For
remote control usage, connect the REMOTEACTIVATION (ON AIR)
terminals, pins 8 (ground) and 9 ofJ3, and the REMOTE RESET ter-
minals, pins
10
(ground) and
11
of
J3,
to
momentary-to-ground switches.
Grounding these lines activates the functions.
h.
If
the 886 will be used
to
activate a station alarm, connect the alarm device
to
the EBS ALARM RELAY terminals, pins 1 thru 6
of
J1
on
the
886
rear
panel. See Figure 2-, Model 886/887 Wiring Diagram,
at
the back of this
section for relay configuration.
1. Ac power is applied through the rear panel ac connector. Connect the line
cord
to
an appropriate outlet.
The
886 should now be on.
2-3
www.SteamPoweredRadio.Com
AM
and
FM
EBS Systems
2.5 FM System Installation
The Model 887 is calibrated and ready for installation into
an
equipment rack for imme-
diate use. Ensure proper environmental conditions exist
as
specified
in
Section
1,
Para-
graph 1.2 of this manual.
The
operating temperature for this unit is between 0°C and
50°C (32°F and 122°F).
To
install the 887, perform
the
following:
a. Mount the Model 887
in
the equipment rack and secure.
b.
If
an
FM receiver is installed, connect a
75Q
coaxial cable from the antenna
to the ANT
75Q
connector on the rear panel
of
the 887.
If
a local
FM
an
-
tenna is not available, a conventional
FM
or
TV
antenna is satisfactory.
c.
If
desired, the
RX
AUDIO UNBALANCED terminals, pins 9 (ground) and
10
of
J1
on
the rear panel
of
the 887, can
be
connected to a monitor or
other external device.
d.
The
RX
AUDIO BALANCED terminals
at
Jl
, pins
11
and
12
on
the rear
panel
of
the 887, can be connected to a monitor
or
other external device.
The
output
at
these terminals is +8 dBm into
600Q
.
e.
If
a remote indication ofcarrier failure is
to
be
provided, connect the CAR-
RIER
FAIL terminals, pins 7 (ground) and 8
of
Jl
on
the rear panel ofthe
887, to the remote indicator.
The
output is
10
Vat
10
mA
for carrier loss.
f.
To
connect the right channel loop thru configuration, connect the program
right channel balanced output to the
AUDIO
LOOP
TIIRU
RIGHT
CH
BALANCED INPUT terminals, pins 4 and 5
of
J2
on
the
887 rear panel.
Connect the stereo generator right channel input line to the AUDIO LOOP
THRU
RIGHT
CH
BALANCED OUTPUT terminals, pins 1 and 2
of
JZ
on
the 887 rear panel. See the wiring diagram for these connections, Fig-
ure
2-1
(Model 886/887 Wiring Diagram), at the back
of
this section.
To
connect the left channel loop thru configuration, connect the program left
channel balanced output to the AUDIO LOOP
THRU
LEFT
CH
BALANCED INPUT terminals, pins 9 and
10
ofJ2
on
the 887 rear panel.
Connect the stereo generator left channel input line to the AUDIO LOOP
THRU
LEFf
CH BALANCED OUTPUT terminals, pins 6 and 7
of
J2
on
the 887 rear panel. See Figure 2-1, Model 886/887 Wiring Diagram,
at
the
back of this section.
g.
To
use the composite loop thru configuration, connect the stereo generator
output
or
composite output to the COMPOSITE LOOP
THRU
IN connec-
tor. Connect the COMPOSITE LOOP
THRU
OUT
connector to the ex-
citer modulation input. See Figure
2-1,
Model 886/887 Wiring Diagram,
at
the back
of
this section for wiring connections.
2-4
www.SteamPoweredRadio.Com
AM and FM
EBS
Systems
h.
For
remote control usage, connect
the
REMOTE
ACTIVATION
(ON
AIR)
terminals, pins 8 (ground)
and
9
of
J3
on
the
887
rear
panel,
and
the
REMOTE
RESET
terminals, pins 10 (ground)
and
11
of
J3,
to
momentary-
to-ground switches. Grounding these lines activates
the
functions.
i.
If
the 887 will
be
used
to
activate a station alarm, connect
the
alarm device
to
the BBS
ALARM
RELAY terminals, pins 1
thru
6
of
J1
on
the
887
rear
panel.
See
Figure 2-1, Model 886/887 Wiring Diagram,
at
the back
of
this
section for relay configuration.
J.
Ac power is applied through the
rear
panel
ac connector. Connect the line
cord
to
an
appropriate outlet.
The
887 should now
be
on.
2.6
AM
Antenna Installation
If a local
AM
antenna
is
not
available,
an
end-fed long wire
antenna
(approximately 250
ft.) can
be
used.
One
end
of
the
long wire should
be
connected to the
ANT
750
connec-
tor.
For
moderately strong signal areas,
an
alternative
to
the
long-wire
antenna
connection
can
be
used.
Refer
to
Figure 2-2,
AM
Antenna Installation Diagram,
at
the back
of
this
section.
2-5
This manual suits for next models
1
Table of contents
Other TFT Receiver manuals
