 The Bank of America Tower in downtown Atlanta |
Our primary site is located at an
elevation of approximately 2000 feet above sea level atop the Bank of
America tower in downtown Atlanta, tallest building in the city. This
site is home to the 146.820-, 224.340-, and 444.825+ repeaters. We would
like to thank Cousins Properties for providing the continued use of this
site to us.
Until November 2000, our antennas has to stay inside the gridwork of aluminum at the roof of the building which caused weak reception at times. We finally won approval to move our antennas out to the base of the obelisk near the peak. Our performance from this location is outstandidng! On 27 December 2000, the ARC installed a brand new, top of the line repeater system at our Bank of America site. A diagram of the new system is available here (Adobe PDF format). The new system runs a Vertex VXR-5000 repeater, controlled by a Link Communications RLC-3 controller. The system uses a Doug Hall Voter to receive signals directly from our remote receive sites and choose which signal to retransmit. The Voter is capable of switching audio between two or more receive sites mid-transmission without any noticable change in the output audio. It allows for a maximum of 32 remote receive sites. |
The RLC-3 controller allows us to connect up to 8 radio cards, each of which can operate as an independent repeater. Currently, the primary 146.820- repeater runs in slot 1. Autopatch capabilities are provided by an autopatch module. Linking to the 440 repeater is now possible. Links to the 220 repeater, as well as the repeaters located at the WFOX site, are currently planned.
The repeater is capable of linking to the Skywarn linked repeater system via the network's hub, 444.675. At times when there is severe weather in the area, the Skywarn link will be activated and the repeater will sound just like the 444.675 repeater. Don't be surprised if you hear unfamilar people carrying on conversations or the courtesy tone/squelch tail is different.
The system utilizes a DVR, or Digital Voice Recorder, for providing voice mail capabilities. Some repeater IDs and tail messages are also stored on the DVR.
Remote Receivers and Voting
 220 receiving antenna at the Bank Tower |
The remotes accept input on 146.22Mhz and require a 146.2Hz PL (CTCSS) tone to open the squelch. Received signals are transmitted directly to the bank tower via the 220 or 440 band using horizontally polarized Yagi antennas. These signals are received at the bank tower and fed into the system's Voter, which automatically selects the strongest signal to use as output audio. The Voter is capable of switching the audio between receive sites mid-transmission without any noticable change in output audio. |
Currently, only one remote receive site has been deployed. It is located atop Sweat Mountain, north of metro Atlanta. Additional remotes are planned for the future.
Antennas and Feed Lines
| There are many antennas
currently running into the system. Most antennas are connected using
ultra low loss hardline, which is absolutely necessary since some of our
antennas are located almost 300 feet above the roof where the
transmitter is located. Antenna feed lines are now color-coded at all
points in the tower for easy identification from a distance.
Our primary antenna for two meters is now located outside of the aluminum gridwork, at the base of the "spire" near the building's peak. From this location our antenna has a virtually unrestricted line of sight to most of metro Atlanta. |
 Color-coded antanna hardline |
Link Communications RLC-3 Controller
 Radio cards in RLC3 controller |
The repeater utilizes a state
of the art RLC-3 digital repeater controller from Link Communications.
The RLC-3 is the largest and most capable controller available anywhere.
It has slots for up to eight radio cards and two Input/Output cards. We
currently use six of the radio card ports and both of the I/O ports.
Each radio card controls input and output for the three repeaters
located at the site, as well as all links. Each card can operate as an
independent repeater. In addition to these critical functions, the RLC-3
also provides synthesized voice capabilities for repeater messages
generated on-the-fly.
More information about this controller is available directly from Link Communications. |
Old Repeater System
Photographs and and information regarding
the old repeater system is available by following this link. Some gear from the old
system is being used in the new repeater system.
Photograph Credits
Photos by Chris Hutton, KF4YDF, unless
otherwise specified. Some photos courtesy Dennis Baggett, KF4MHW and Jack
Yeazel, N4TEB.