User Manual

Table Of Contents
DE
DANIELS
ELECTRONICS
UT-4R400 UHF Project 25
Digital
Transmitter
Instruction
Manual
4-3
separate
control of their
channel
select
lines, so changing
receiver
channels does not
affect
the
transmitter
channel.
Q: Why is the
transmitter
staying on after the
receiver
signal is
removed?
A: The
transmitter
has a hang
timer
that keeps it keyed after the
receiver
signal disappears. This
can be used to keep a chain of
repeate
rs up between transmissions. The delay is
adjustable
from 0
to 3.75
seconds.
Q: What’s that noise at the end of a transmission?
A: The
transmitter
can insert an
audible
“kerchunk”
at the end of a
repeater
transmission. In
Project 25
digital
mode, this
simulates
the
effect
of the squelch noise, which is heard at the end of
an analog
repeater
transmission. In analog systems, the squelch noise is the sound of the
receiver’s
IF noise before it squelches. This is often useful as a
confirmation
to
repeater
users that
they have
“hit”
the repeater. In Project 25
Digital
mode, no noise is heard at the end of a
transmission due to the
all-digital
nature of the system, so an
artificial
noise is added to serve the
same
purpose.
There is a jumper on the
transmit
ter’s microprocessor board to disable the
kerchunk noise.
Q: Why is the Radio Service Software
failing
partway through a read or write of the
receiver?
A: If the
receiver
is squelching and unsquelching
repeatedly
during the read or write operation, the
communications
bus may be too congested. Try changing channels on the receiver, or
disconnect
the RF signal source from the
receiver
during the read or write operation.
Q: Why does the
transmitter
not
transmit
with the
correct
TGID or NAC, or in the wrong mode?
A: In a
typical
repeater, if the
received
signal is digital, the
transmitter
will be keyed from a bank B
channel, NOT from bank A, even though the
receiver
may be
receiving
on a bank A channel.
Make
sure that for each
transmit
channel
number, both the A and B bank are
programmed
with
analog
information
and Project 25 information, respectively.