MT-6250B/GRC-206 Program Pacer Speak System Rack
© Brooke Clarke 2008
The GRC-206 Program Pacer Speak is a collection of radios used for
Forward Air Control. This rack holds the radios and related
equipment in a size that's compact and fits a HMMWV
or other military vehicles. I cut the pallet that it was shipped
on in half, leaving the center 2x4. This keeps it up off the
concrete floor and makes it a little higher for ease of access.
When the GRC-206 is mounted in the M998 HMMWV it's called the MRC-144.
The system draws up to 1500 Watts at 24 VDC or 63 Amps. The
MEP-802 diesel gen set is only rated to supply 16 Amps from it's NATO
slave battery charging connector, but is rated for 5,000 Watts on the
60 Hz AC output. The implication is that the M455-1
can convert the AC into 24 VDC to power the system. But the
connectors on the M455-1 are not as large as the input connectors on
the SB-4151 so the use of the M455-1 is unknown.
Variants/Upgrades
The first four versions were
designed at the start. (V)1 and (V)3 have crypto and (V)2 and (V)4 do
not have crypto. The GRC-206 system specific boxes were
designed to allow for optional crypto and/or Have Quick operation.
Some speculation as of Dec 2008
|
(V)1
|
(V)2
|
(V)3
1987
|
(V)3+
|
(V)4
|
(V)5
1999
|
(V)5
|
(V)6
| (V)?
|
HF
|
URC-113
|
URC-113 |
URC-113 |
PRC-138 |
URC-113 |
URC-113 |
URC-113
|
URC-113
| PRC-138
|
VHF-FM
|
RT-246
VRC-46
|
RT-246
VRC-46
|
RT-246
VRC-46
|
|
RT-246
VRC-46 |
SINCGARS
VRC-91A
ANDVT (FAS)
|
SINCGARS
VRC-91A
ANDVT (FAS)
|
SINCGARS
VRC-91A
ANDVT (FAS)
| SINCGARS
VRC-91A
ANDVT (FAS) |
Crypto
|
KY-65
KY-57 (3)
|
No
|
KY-65
KY-57 (3)
|
|
KY-65
KY-57 (3)
|
?
|
No
|
KY-99A
KY-57 (2)
| KY-99A
KY-57 (2)
|
Have Quick
|
No
RT-1319
|
No
RT-1319
|
Yes I
RT-1319B
|
|
Yes I
RT-1319B |
Yes II
RT-1319C
|
Yes II
RT-1319C
|
Yes II
RT-1319C
| Yes II
RT-1319C |
SATCOM
|
No
|
No
|
No
|
|
No |
No
|
No
|
| UHF DAMA (FAS) |
RFO
|
No
|
No
|
Yes
|
|
No
|
Option
|
Option
|
Option
| GPS
|
Weight (lbs)
|
368
|
308
|
418
|
|
|
|
|
|
|
Prime Pwr
|
MEP-025
Gas DC Gen
|
MEP-025
Gas DC Gen |
MEP-025
Gas DC Gen |
|
MEP-025
Gas DC Gen |
MEP-802
Diesel AC Gen |
MEP-802
Diesel AC Gen |
?
|
|
Inverter ?
|
No
|
No
|
No
|
|
No
|
?
|
? |
?
|
|
Rack
|
MT-6250?
MT-6251?
|
MT-6250A
|
MT-6250B
|
MT-6250
|
MT-6250
|
MT-6250E
|
MT-6250E
|
MT-6250E
|
|
? The URC-113A uses the RT-1444A which has ALE
capability. But the AM-7148 does not look like it can handle ALE,
hence the need for the PRC-138.
(V)3 systems were converted into (V)5 systems in Texas by replacing the
VRC-12 radio with SINCGARS radios and replacing the BITE/Audio
Interface box.
The manuals for (V)5 and (V)6 show the same BITE/Audio Interface box
and so far do not show how the remote can select the VHF-FM channel.
This description of the varients might be wrong or incomplete
GRC-206(V)1. Includes provisions for user-supplied
COMSEC devices.
GRC-206(V)2. Does not include these provisions, but
space is available for other user-selected components.
GRC-206(V)3. Is identical to the (V)1 except that
electronic counter-countermeasures (ECCM) are provided within the UHF radio
set.
GRC-204(V)4. Combined with the Meteorological
Measuring System and ancillary equipment, this model is installed in a HMMWV to
form the TSQ-198 Tactical Terminal Control System (TTCS) for the US Army.
PSN-11 GPS capability is also provided.
GRC-206(V)5. Modifies the (V)3 to incorporate the
SINCGARS radio and the USC-43(V) Advanced Narrowband Digital Voice Terminal
(ANDVT). Built-In Test (BIT) functions were also enhanced.
GRC-206(V) P3I. As part of preplanned
product improvements, the GRC-203(V) can accommodate a PSC‑5 enhanced
man-pack UHF transceiver, either as an addition or by replacing an existing
component (such as the RT-1319). Improvements include UHF/FM SATCOM and DAMA,
8.3 kHz channel spacing in VHF/AM for ICAO air traffic control in Europe, TDMA
in VHF/AM for US civil (Federal Aviation Administration) air traffic control,
SATURN ECCM in UHF/AM for NATO, expansion of the UHF band to 512 MHz for civil
command and control, and video compression imagery.
While reading FM 3-52.3 (learning about bedwindow gingerbread
procedures) it mentiones that the AN/TSQ-198 is a HMMWV mounted ATC
system consisting of the:
- VRC-83 - VHF AM low and UHF AM aircraft bands
- VRC-90F - VHF low FM
- ARC-220 HF (Ground version is the VRC-100) from FAS this is a Nap-Of-The-Earth HF system:
The AN/ARC-220(V) and its ground version, the AN/VRC-100(V) will
replace the
AN/ARC-199(V) and AN/VRC-86(V) respectively. Secure communications will
be achieved through the use of the KY-100 Crypto Set. The
AN/ARC-220(V)1 consists of three line replaceable units; a
Receiver-Transmitter (RT), a Power Amplifier Coupler (PAC), and Control
Display Unit (CDU). The AN/ARC-220(V)2 is for bussed (1553) aircraft
and consists of just the RT and PAC. The AN/VRC-100(V)1 consists of the
three LRU's housed in a metal casing along with a power supply and
speaker.
The AN/VRC-100(V)2 is the AN/VRC-100(V)1 mounted on a HMMWV along with
associated brackets and antennas. The AN/VRC-100(V)3 is for Echelons
Above Corps and consists of the AN/VRC-100(V)1 with the AS-3791/G
Broadband Antenna.
Timetable
|
|
1981
|
Magnavox
awarded production contract
|
|
Late
|
1983
|
First
units delivered
|
|
Mar
|
1991
|
Last
production contract awarded for US Air Force
|
|
Sep
|
1993
|
Contract
awarded for retrofit/upgrade to (V)5 standard
|
|
|
1994
|
GRC-206(V)4
selected for US Army TTCS program
|
|
|
1995
|
Corporate
acquisition transferred GRC-206(V) business to Hughes
|
|
|
1997
|
Hughes
absorbed into Raytheon Systems Company
|
|
Sep
|
1999
|
Raytheon
received US$25 million contract for Foreign Military Sale of GRC‑206(V)
to Greece |
New Old Stock
This rack was New Old Stock. The packing bag label:
FSCM 37695 P/N 812084-803
1 EA EQPT MTG RACK
s/n AH0036
INCLUDING:
1 EA P/N B812132-801 FM BITE
s/n AH0039
1 EA P/N 5810-01-050-7184
KY-65 MOUNT
1 EA P/N 5820-00-893-1323
VH-FM MOUNT (MT-1209/VRC)
The standard four foot square pallet gives some idea of size.
As Received
Front View
In the photo at left it can be seen that the MT-6250B rack comes with all the equipment mounts and a lot of the system cabling.
Top Left VRC-83: 5 connectors
Top Center: O-1814: 2 connectors
Top Right: URC-113: 4 connectors
Middle Left: two KY-57: 3 connectors each
Middle Center: KY-65: 2 connectors
Middle Right: SDU: 6 Conn & PDU: 5 conn + rear input
Lower Left VRC-83: 5 conn
FM Bite/Audio Interface box: AS-1729, VHF-FM, SDU
third KY-57: 2 conn.
Lower Right: VHF-FM: 4 conn.
Back View
At
the middle elevation left side is a box that connects to the back of
the Power Distribution Unit (PDU) and has vehicle DC power cables for
each of the system boxes.
37 7/8" wide x 16 1/8" deep x 30 3/8" hi.
There are two folding handles on the left side and two more on the
right side. I think that's for four men to each have a handle if
the rack was loaded, or a two man carry empty. The two man empty
carry is because of bulk more than weight.
The HF radio sits in the upper left corner of this back view.
There is a cable clamp on the back of the rack just below where the
AM-7148 power cable connects (just above the PDU location).
The box at the left center is behind the SB-4151 PDU and the cables out
the back are the DC power cables feeding most of the rack
equipment. The exception is the front panel cable to the RFO.
Remote Mount p/n 812805-801
System 9 Jan 2009
There are two Remotes, but only one FO cable so the second one can not be connected.
The Power Supply is maintaining the Cyclon back up batteries inside the
RFO. The green lamp above the power switch is on and the third
lamp to it's left (under the cable) is Red indicating SET CLOCK.
Two HYP-57 Wire Line Adapters are filling the KY-57 slots for the aircraft radios.
Upper left has a couple of battery boxes from the HYP-57s, too long to leave on.
KY-57 filling the slot for the VHF-FM radio.
SINCGARS VRC-87 sitting in the VHF-FM radio slot, but it will not
operate unless the MT-1029 is removed. But the AM-2060 with a
PRC-77 would fit the MT-1029 and you could connect the BITE/Audio
Interface and the audio so the remote would work with it.
Although there is only one channel.
The M455-1 is just sitting at the lower left corner. It's a little shorter than the RT-1319.
Bite Audio Interface
NSN: 5895-01-192-1190
p/n: 812132-801
|
|
MT-6250B Bite Audio Interface Front
|
MT-6250B Bite Audio Interface Back
|
The FM Bite box marking AS-1729 suggests that this rack was designed to hold a VRC-12 series radio instead of a SINCGARS radio.
Also the mount in the lower right corner looks like the
MT-1029 which would hold a
VRC-12
series receiver like the RT-524 w/speaker or RT-246 with 10 remote
controled channels. There is no J-3513 in the MT-1029 like in
normal VRC-12 series radios with the KY-57 so it's function must be
done in the BITE/Audio Interface.
It's looking like the RT-246 that has 10 channels that can be selected
remotely is what went into this rack. That means that the SDU
and/or BITE/Audio Interface contain circuitry that allows serial
control (since it must be done over the fiber optic link) of the
channel. This serial protocol may match the SINCGARS serial
channel selection protocol?
Why the BITE/Audio Interface has the VHF-FM antenna connection is also a mystery.
Connectors
J#
|
Label
|
Function
|
J1
|
AS-1729
|
RF to/from AS-1729 Antenna
|
J2
|
VHF-FM
|
RF to/from radio
|
J3
|
SDU
|
"Y" cable to SDU and REMOTE on radio
|
J4
|
VHF-FM |
X-Mode & (ReTrans or Audio) on rradio
|
J5
|
KY-57
|
KY-57 RADIO connector
|
In a crypto system the handset is
connected to the KY-57 and so the PTT for the radio comes from the
KY-57, through the BAI box then to the radio.
When no crypto the VHF-FM audio cable from the SDU is connected to the Retransmission connector on the radio.
There is no connection to the radio AUDIO connector in the system.
The RT-246 or RT-524 has the internal crypto switch left in the plain
text position for both unsecured and secured coms.
When the BAI box is connected to the radio it makes the same connection
that the internal switch would have made. That way it's easy to
unplug the BITE box to get back to plain text transmissions without
opening up the radio.
BAI J2
Pin
|
Signal
|
SDU-J11
|
A
|
Ground
|
U
|
B
|
CT or PT
|
Z
|
C
|
BITE
|
Y
|
D
|
+12 V
|
X
|
E
|
DC Rtn
|
W
|
F
|
Spare
|
/E
|
BAI J4
Pin
|
BAI Signal
|
RT-246
|
|
X-Mode
|
Audio
|
A
|
ground
|
F
|
-
|
B
|
TR Relay
|
K
|
-
|
C
|
X-Mode to Tx
|
G
|
-
|
D
|
PT in from Tx
|
E
|
-
|
E
|
PT out to Rx
|
C
|
-
|
F
|
X-Mode in from Rx
|
A
|
-
|
G
|
Tone K401-5
|
D
|
-
|
H
|
Tone Mode
|
J
|
|
J
|
Mic Audio
|
-
|
D
|
K
|
Un Muted Audio
|
-
|
B
|
L
|
ground
|
-
|
A
|
BAI J5
Pin
|
Signal
|
KY-57 RADIO
|
A
|
PT Out
|
K
|
B
|
Squelch Control
|
T
|
C
|
CT In
|
D
|
D
|
CTOIP
|
E
|
E
|
PT In
|
M
|
F
|
Rx PT
|
C
|
G
|
Rx CT
|
A
|
H
|
PTT
|
S
|
J
|
PTO Rtn
|
L
|
K
|
ground
|
G
|
The BAI replaces the J-3513 and by sampling the RF during Tx generates a bit of BITE.
Prime Power
System versions (V)1 through (V)4 were powered by the MEP-025A 1.5 kw gas DC generator. It weighs 121 pounds dry.
Later versions use the
MEP-802A 5 kw 60 Hz AC diesel generator
skid mounted tatical quiet It weight 800 pounds dry. Since the DC
output from this generator intended for battery charging can not supply
enough current for the GRC-206 system an inverter is needed. The
M455-1
accepts either DC or AC inputs and provides 28 VDC output as one of
it's outputs. But the connector contacts look too small for the
50 Amps needed by the GRC-206. So it's not clear how the MEP-802A
can power the GRC-206?
Vehicles
System versions (V)1 through (V)4 were intended for mounting on either the M151 Jeep, M113 Armored Personel Carrier.
The Generator and it's fuel tank would be on the 1/4 Ton M-416 trailer.
Later systems are typically mounted on the M998
HMMWV.
First Power
Main Power Input
The main input connectors has a 24-22 Insert and pins that are 0.144" diameter.
The cap is marked 8544 Cannon CA121003-908.
Pin A is +24 Volts and pins B & C are ground. Maybe pin D is
also hot? That way the two top pins would be hot and the bottom pins
ground.
SB-4151 PDU
When 30 volts is applied to A and D the RFO receives power no matter
how the SB-4151 switches are set. Notice that J3 is not in the
box with the lower switch, J1 & J2, i.e. it's hot all the time.
But the green power light does not turn on when the mode switch is at
M-G or Vehicle, but only in Vehicle Override as shown at left.
The power connector on the back of the AM-7148 is only hot when in the Vehicle Override position.
The input voltage in the photo is 29.8 yet the voltmeter on the PDU is
reading about 20. When the mode is switched from Vehicle Override
to Vehicle the green lamp slowly (maybe 5 seconds) dies out like there
was a big capacitor discharging.
Maybe this PDU is defective?
The row of aux pwr banana jacks are switched on or off independent of the Master reset switch.
Jacks J1 & J2 switch on or off independent of the master power switch.
The current on the power supply is caused by charging the batteries in the RFO.
AM-7148 URC-113
The RT-1444 is not yet installed so the remote control cable is laying
in front of the AM-7148. The RT-1209 is installed. But when
the mode switch is set to STATUS or MODULE TEST nothing happens, as if
it was not getting any power.
Remote
Both the PWR and FO cables are connected, and there's one internal
battery, but when the BATTERY switch is turned ON the red lamp comes
on, the fault tone is heard and the status display shows Cable
Fault. It's as if it was not working.
Second Power
After opening up the SB-4151 it was
discovered that J4 the Vehicle input jack MUST have pin D grounded in
order for the contactor in the SB-4151 to actuate turning on the system.
Once that's done then the AM-7148 does the module test and the Remote
no longer shows the cable fault error. Also the remote allows
keyboard entries, like setting a frequency, but since there's no radios
now connected gives an error beep when you try to enter the frequency.
16 Jun 2009 Photo
The RT-1319 is in the upper left UHF AM military air band position. But the RF amp is still missing.
The RT-246 is in the lower right VHF FM military ground and air position.
All three KY-57 slots have been filled, but need to add internal jumpers to pass clear text.
The M455-1 needs some unknown front panel jumper or wiring to get it to turn on.
Have a linear power supply that should be able to power one radio and cable with plug to fit SB-4151.
Related Web Pages
GRC-206 Program Pacer Speak
C-11166 Universal Remote System Control URSC
C-11169 Signal Distribution Unit SDU
SB-4151 Power Distribution Unit PDU
O-1814 Reference Frequency Oscillator RFO
PRC-104 Manpack HF radio
RT-246 VHF FM Radio
RT-1319 VHF AM Aircraft Radio
RT-1444 Remote Control adapter for the RT-1209 (PRC-104)
KY-57 Transmission Security Device for VHF and UHF radios
KY-65 Narrowband Secure Voice Unit for HF radios
GRC-206 Cables
VRC-83 Vehicle version of PRC-113 with RF Amp Aircraft radio covering VHF-AM and UHF-AM bands
There are three versions of the
RT-1319, the first did not use "Have Quick", the second used the first
version of Have Quick and the third used Have Quick II.
The RFO is in this system specifically to supply the RT-1319 with TOD
for Have Quick, so this system uses either of the Have Quick versions
of the radio.
HMMWV Hummer 1 ¼-Ton, 4X4
military vehicle - M998 used for MRC-144
AT-1011 HF Whip Antenna
AS-2259 HF NVIS Antenna
AS-1729 VHF-FM Ant
UHF-AM antenna?
VHF-AM antenna?
MT-1029 (lower right mount for VHF-FM)
VRC-12 Series Radios
RT-246 VHF-FM Radio
M455-1/GRC-206 Power Source (but pins are only 0.063" dia)
EMCU 116 12 VDC Input 24 VDC Output - The
pins on this supply are the same size as the GRC-206 input pins and so
may be more suitable to power it.
(V)5 Systems replace the VRC-12 series radio with SINCGARS & Replace the KY-65 with a KY-99A
SINCGARS VHF FM tactical radio,
RT-1439
KY-99 Advanced Narrowband Digital Voice Terminal (ANDVT) Family
(
FAS web site)
Sources of GRC-206 Items
Mike Murphy
eBay seller lonym
eBay seller
art-in-part
eBay search for GRC-206, URC-113, VRC-83, VRC-87, RT-1319, VRC-89,
Columbia Electronics - Paul Keys has many of the system parts and supports it to government buyers
William Perry - good source for connectors
Links
A Close Call - "Airmen like Senior Airman Courtney Hinson, a terminal
attack controller, are entrusted with an MRC-144 weapons system —
a half-million dollars in communications equipment housed within a Humvee.
As part of the 18th Air Support Operations Group, supporting 18th Airborne
Corps, Hinson and his comrades are responsible for keeping their systems
and the mission running. And testing frequencies is part of knowing the
system."
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