Installation; Antenna Considerations; Equipment Location - Vertex Standard VXR-7000 Operating Manual

Antenna Considerations

Repeater operation without a duplexer requires that two
antennas be installed, one for receiving and one for
transmitting, so that the receiving antenna does not ab-
sorb energy from the transmitting antenna. There are a
number of ways to do this, depending on the TX/RX
frequency separation, and on the locations available for
antenna mounting. If a duplexer is used, a single an-
tenna suffices for both transmitting and receiving. If
using a reduced-size duplexer, a six-cavity model (mini-
mum) is recommended. Vertex Standard recommends
the use of the duplexer. For further details, contact your
Vertex Standard dealer.
Regardless of the above choice, it is of paramount im-
portance that the antenna(s) be mounted as high and in
the clear as possible, preferably within line-of-sight to
all repeater users. Furthermore, losses in the feedline(s)
must be minimized, so the feedline(s) should be high
quality, and as short as possible. If a long feedline is
necessary, use coaxial "hardline" cable to reduce losses.
Repeater antennas should have an impedance of 50 Ω
at the operating frequency. When separate receive and
transmit antennas are used, high-Q narrow-band types
may serve to minimize interaction. However, when a
single antenna is used with a duplexer, it should be a
low-Q wide-band type.
NEVER TRANSMIT WITHOUT HAVING A
TRANSMIT ANTENNA CONNECTED TO THE
TX ANTENNA JACK OF THE REPEATER.
VXR-7000 FM R
EPEATER
O M
PERATING ANUAL
AC Power Supply Voltage Selection
Each repeater is wired for a particular AC mains volt-
age between 100 and 253 VAC. This should be indicated
by a label near the AC jack on the rear panel. If no label
is present, or if the AC voltage on the label is different
from the local AC line, check the wiring inside the
Switching Regulator Unit of the repeater, and change
the connections (and label) if necessary, as shown next
page.
Changing the AC input voltage wiring also requires
changing the fuse on the FILTER Unit if the voltage is
changed from 100 VAC (100-127 VAC) to 200 VAC (207-
253 VAC), or vice-versa. Use a 5-amp fuse for 100 VAC,
or a 3-amp fuse for the 200 VAC.
DC Power Supply Backup
For uninterrupted operation during power failures, a
12 volt rechargeable type battery (55-Ah or more rec-
ommended) may be connected to the BATT terminal
posts on the rear panel. While the repeater is operating
from the AC source, a slight charging current will main-
tain battery charge. In the event of an AC power out-
age, the automatic power control circuit will automati-
cally switch the repeater to the backup battery, and op-
eration will not be interrupted.
After prolonged operation from the battery, it should
be disconnected from the repeater and recharged sepa-
rately before re-connecting, as the trickle charge is not
sufficient for recharging a completely discharged bat-
tery.
Never reapply AC power to the repeater with a dis-
charged battery connected, as the DC startup current
can damage the repeater and battery.
While operating from a battery or DC supply, the re-
peater requires approximately 7 amperes at 12 Volts dur-
ing transmit.

Equipment Location

While the operating temperature range of the repeater
is quite broad, the best location is one in which the air
temperature does not approach the extremes of the
specified range, and one that does not change rapidly.
Make sure to allow for free air flow around the heatsink
on the rear apron at all times. In warm climates, the re-
peater should not be sealed in a small closed room.
Protect the repeater from wind and rain, and extremes
in temperature or humidity that may shorten the useful
life of the equipment. Try to locate the repeater in an
environment that is also comfortable for service person-
nel, if possible.

Installation

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