RT-246 Military VHF Low Band Vehicle Radio, VRC-12 Family
© Brooke Clarke 2009 - 2010
Background
Spares
Test Equipment
VRM-1
Links
Background
This is one of the VRC-12 series
Military VHF low band vehicle radios. The others are the
RT-524 ( very similar to the RT-246 but w/o the pushbutton tuning
and w/speaker) and the R-442 receiver. It interoperated with
the
PRC-25,
PRC-77,
PRC-68,
PRC-68A,
PRC-68B,
PRC-126
and the low band version of the
PRC-128.
It
also
has
provision
for
communications
security be adding an external
KY-38
or
KY-57.
I got this radio for the
GRC-206
system which was designed to allow remote channel selection.
It fits into the lower right corner of the
MT-6250
equipment rack.
This radio is in the
VRC-12 family
and works with the Vehicle Inter Communication (
VIC) equipment
Spares
These parts came from an RT-524 and
many of them are common to the RT-246.
Note: The
RT-823/ARC131
uses some of the same modules as the RT-246. I expect the
R-442 and RT-524 also have common modules, i.e. most of the VRC-12
family.
Test Equipment
AN/VRM-1 NSN: 6625-00-892-5542
Major Components:
TS-1777 Test set
MX-7899 "Y" cable
The probe contains an AC coupled RF amplifier and a choke isolated
DC line so can be used for both types of testing. All solid
state construction.
|
TS-1777/VRM-1
|
|
Notice the spare lamp and
probe tip in the upper left corner.
The instructions are divided into sections:
- Generalized Test Procedures
- Audio Assy A5000
- IF Assy A4000
- Crystal Ref System A3000
- Modulator Assy A8000
The switch position determins the type of measurement and
test limits.
Where the probe is placed determines what gets measured.
So for a given assembly there may be multiple tests with the
same switch
position on different test points.
|
|
VRM-1 Y Cable
The large MCM block connector plugs into the back of the
radio.
The large round connector plugs into the three sockets on
the right of the MT-1029
MCM block connector. (Note the large round connector
can be plugged into the MCM block connector (A, B & C)
on the cable. the the mating terminals are wired
1:1) B&C on the large MCM connector are tied
toghther and to to either pin B on the small circular
connector.
Pin A on the large MCM block goes to either pin A on the
samll cir conn.
MCM
Block
|
MCM
Cir
|
Small
Cir |
Function
|
A
|
A
|
A
|
Ground
|
B
& C
|
B
& C
|
B
|
+24
VDC
|
The small circular connector plugs into the VRM-1.
|
VRM-1 Manuals
TM 11-6625-496-12
TM 11-6625-496-20P
TM 11-6625-496-45 Field & Depot Maint (w/schematics)
TB 11-6625-496-35 Cal Procedure for Radio Test Sets, 12 pgs
U.S. Army Training Film
Links
Pvt Jar Head - RT-246
eBay - spare parts
Fair Radio Sales - VRM-1
Back to Brooke's Products for Sale,
Military Information, PRC-68 Family of Squad Radios, U229 Audio Accessories, Audio Connectors, Electronics,
Home page
page created 14 June 2009.
