Radio Shack Simplex Repeater Controller (19-345)
Conversion for use with Military radios with U-229 Connectors
© Brooke Clarke 2000 - 2007
General Information
This product may not longer be offered by Radio Shack. For info
on Simplex Repeaters see the Simplex
Repeater web page and there's also a Yahoo Group for them.
This unit is made up of a 30 second digital voice recorder and some
circuitry
to turn on the recorder when audio is present and to play back the
message
when the audio stops. By connecting to a single
Receiver-Transmitter
the combination becomes a Simplex Repeater.
The interface to the radio consists of only three wires:
- Ground
- Microphone
- Earphone
It is not clear to me how this keys the transmit function in a Family
Radio
Service (FRS) for which this unit was designed. Although I
have heard that it will work with the Radio Shack 2 meter radios.
In order to get it to work with the PRC-68B and PRC-126 I added a
4.7
K Ohm resistor (RS 271-1330) and a 2N2222A (RS276-2009) transistor plus
a cable with a U-183 AUDIO connector. A standard U-229 type cable
could be used since the center pin is not functional in this
setup.
The cable was from eBay and is sold as a KG-99 to PRC-104 Crypto-Audio
cable. The 26 pin connector (MS3126E16-26P) was wired with the
pin
letters matching the pin letters on the UG-183 (A to A...F to F).
It is wired as follows:
- AUDIO A = Black = Ground = printed circuit board ground
- AUDIO B = Red = Earphone = solder pad for ear
- AUDIO C = Orange = PUSH TO TALK = collector of 2N2222A
- AUDIO D = Blue = Microphone = solder pad for mic
- AUDIO E = Green = External Power = center solder pad next to
power
connector
- AUDIO F = White = FILL = not used here
- no connection = Brown = no connection
By wiring the AUDIO E wire to the external power supply pin on the
19-345
the external 12 VDC power adapter (RS-273-1662 w/ + to tip) will also
power
the PRC-126 or PRC-68B radio but NOT the PRC-68. The 19-345
may control the PRC-68 and supply power if the switch on the PRC-68 is
set to OFF! In this position the radio runs from the AUDIO pin E
power supply. The 300 mA transformer shown n this page does not
have
enough current to drive the 19-345 and the PRC-68 so a 500 mA wall wart
is needed.
Note that the volume control of the RT being used as the repeater
must
be adjusted for best sound quality. If it is set all the way down
the 19-345 will not hear the audio.
Photo of component side of stock
printed
circuit board showing the voice chip and what may be an 8 pin PIC
microcontroller.
Pin 3 on the microcontroller is the high = play pin.
 |
 |
Before Mod
|
After Mod
|
Here is another way to make the conversion to mil radio use by Federico
Torres, KP4KSL Annotated Photo.bmp
-
P.H.S.Ltd
-2-Way
Radio Range Extender -
Back to Brooke's Military Audio
Accessories,
U-229 Audio Accessories,
Military
Audio, Products for Sale, Squad
Radio, Military Information,
Home
This is the 06408 hits since May 04 2007 time
this
page has been accessed since since 20 Dec 2000.
