©1994 Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. Revised: 1/31/00
- Page 2 -
module in a Hamtronics REP-200 Re-
peater is on the rear panel of the en-
closure near the receive coax
connector. This is convenient for con-
nections to the feedthrough capacitors
on the partition, and it allows easy ac-
cess to the pots for adjustment. The
module is designed to be mounted with
the pots at the top, just below the up-
per edge of the box. To locate the
mounting holes, draw a line one inch
below the top of the box. Then, mark
the two mounting holes 1-7/8 inches
apart on the line, with the first hole
about 1 inch from the side partition.
Attach the module with 4-40 screws
and standoffs or spacers as desired.
HOW TO MAKE
CONNECTIONS.
Connections are made with the
hookup wires previously soldered to
the terminal pads on the module. Be
sure to read the discussions below if
you have not installed a TD-3 before.
B+ for the unit is connected to the
red wire on E4. The negative supply
normally is connected through the
mounting hardware to the chassis.
Since an 8 volt regulator is used in the
TD-3, B+ can be anything from 10 to
15Vdc.
The most convenient place to pick
up B+ and COS lines is at the feed-
through capacitors on the partition.
The discriminator connection must be
made at the discriminator terminal on
the receiver, since this line is not
available at any of the feedthrough ca-
pacitors. If you wish to use touch-
tone control to disable the tone de-
coder, you will need to add another ft
capacitor to the receiver partition and
a wire from the other side of the ft cap
to the auxiliary control output of a
touch-tone controller.
TABLE 3. NORMAL HAMTRONICS
REPEATER CONNECTIONS.
TD-3 E1
(orn)
to rcvr disc term
TD-3 E2
(blu)
to rcvr COS term
TD-3 E4
(red)
to rcvr B+ term
TD-3 E3
(brn)
to control board aux
function via new ft cap.
AUDIO INPUT.
Audio from the receiver normally
should be picked up from the dis-
criminator for connection to E1. Some
later model receivers have a terminal
pin on the receiver for the discrimina-
tor audio. On earlier models which do
not have a dedicated terminal, the dis-
criminator audio is accessible at the
resistor/capacitor junction of the de-
emphasis network as follows.
In earlier model R144 Receivers,
connect to the right hand lead of R23,
at the junction of C38. In the original
R451 Receiver, connect to the right
hand lead of R29, at the junction of
C45. In the R76 Receiver, connect to
the junction of R20 and C34.
Input transistor Q1 normally gets
its bias from the discriminator in
Hamtronics receivers; so there is no
bias resistor in the Q1 base circuit. If
you are operating from a receiver other
than ours, it is necessary to provide a
680K bias resistor from E1 to the 8
Vdc supply line in the TD-3 and to
connect a blocking capacitor of 0.1 uF
or larger in series with the audio input
so the external circuit is does not pro-
vide a dc path.
OUTPUT CIRCUIT.
Output terminal E2 is connected to
the receiver circuit being switched.
Normally, the unit is used to inhibit
the repeater by grounding the COS
signal from the receiver to the COR
board in the repeater. The easiest
place to connect is at the COS terminal
on the right side of the receiver.
OPTION FOR RECEIVER
AUDIO MUTING.
If the unit is used in a transceiver
system to mute the audio instead of in-
hibiting the transmitter, then E2 can be
connected to short the audio to ground
somewhere in the path from the dis-
criminator to the output stage. There
must be a fairly large series resistor
(larger than 10K) in the audio path be-
fore the connection from E2. Be care-
ful not to connect the shorting output
of E2 in such a way that it shorts the
source of tone signal to the TD-3. In
such installations, the tone should be
taken close to the discriminator, and
the shorting connection should be ap-
plied later in the signal path after a
large resistance. It may be necessary
to add this resistor to the audio path.
OPTION TO CONTROL
TD-3 ON/OFF WITH
TOUCH-TONES.
If a our COR-5 Computerized Re-
peater Controller or the TD-2 (or
similar) DTMF Decoder/Controller
Module is used to turn the subaudible
tone feature on and off remotely, or if
a front panel switch is required to dis-
able the subaudible tone function,
merely connect it to ground E3 on the
TD-3 when you want to disable the
tone squelch function. When a ground
is applied to E3, output transistor Q2
is inhibited from generating a ground.
This option requires an extra feed-
through capacitor to be installed on the
repeater's receiver enclosure. If the
TD-2 DTMF module is used, the re-
peater will default with the subaudible
tone function enabled.
OPTION TO TRANSMIT
ENCODED TONE.
In most repeaters, it is unnecessary
to retransmit the subaudible tone; it is
only necessary to inhibit the repeater if
a station is heard without the proper
tone. If you wish to have your re-
peater retransmit the tone, do the fol-
lowing.
a. Add an extra feedthrough ca-
pacitor on the receiver enclosure be-
hind the others, and add an extra
feedthrough capacitor on the exciter
enclosure about in line with the devia-
tion pot on the exciter.
b. Connect a hookup wire from E5
on the TD-3 to the added feedthrough
capacitor on the inside of the receiver
compartment. Continue with a wire
from the ft cap on the outside of the
receiver compartment over to the ft
cap at the outside of the exciter com-
partment.
c. The connection to the exciter
depends on which exciter you have.
For the TA51 (vhf) Exciter, run a
short hookup wire from the ft cap on
the inside of the compartment over to
the loop at the top of R22. This in-
jects the audio directly into the low
pass filter at the input of the modula-
tor. For the TA451 (uhf) Exciter,
connect a 47K resistor from the ft cap
on the inside of the compartment over
to the lead of C11 closest to deviation
pot R15. This also injects the tone
into the modulator, but the 47K resis-
tor prevents loading of the circuit in
the uhf exciter.
d. If you are using your transmit-
ter for an application other than a re-
peater, you probably do not need the
