User Manual

Exalt Communications, Inc.
Exalt i-Series Installation and Management Guide
5000001 107
2007-06-25
DC Coupler for Antenna Alignment
One challenge associated with an all-indoor radio construction is the alignment of the
antennas. It can sometimes be challenging to place the radio near the antenna alignment
personnel, and can also be challenging to run a separate set of wires for the voltmeter to
be in view of the alignment personnel. If any of the conventional methods mentioned in
the manual are difficult to achieve, one of the simplest methods to use is to employ the
use of a DC coupling system as a temporary test configuration exclusively for the
purpose of aligning the antennas.
This type of system simply couples the DC voltage associated with RSL measurement at
the radio location, over the RF transmission line, up to the antenna port.
Warning: Remove all DC-blocked lightning arrestors in the
transmission system prior to applying the DC coupler system.
Failure to do so can result in electric shock and/or damage to the
lightning arrestors and/or other equipment.
Required Items
The following items are needed for the DC coupling system, per radio end (double the
quantities of these items for a complete link for simultaneous use at both ends):
• 2ea DC couplers: mini-circuits ZNBT-60-1W
• 1ea BNC male-male extension cable: Pomona 2249
• 1ea BNC female-to-mini Bantam (stackable Pin-tip plugs): Pomona 3221
• 1ea BNC female-to-banana male: Pomona 5268*
• 1ea digital volt meter
*This type of plug is typical for most professional hand-held digital volt meters (DVMs).
However, verify that your DVM can accept this type of Bantam connector. If not, a
different part number or adapter may be required to connect to the DVM.
Interconnections
Connect the items as shown in Figure 42. For the coupler installation, ensure that the DC
side of the coupler is facing away from the radio and away from the antenna – towards
the RF transmission line system. Using the BNC adapters and cables, attach the radio end
DC coupler to the RSL port on the radio, and the antenna end DC coupler to the DVM
that the antenna alignment personnel will use.
The DC voltage from the RSL port is now coupled to the transmission line system
between the radio and the antenna, and is available at the antenna location. This allows
the antenna alignment personnel to view the DVM output directly while adjusting the
antenna.