It is often said that Cartersville, GA, is 45 miles north and 100 years away from the hustle and bustle of Atlanta. So it is understandable that a community that has been cited as one of the 100 Best Small Towns in America would want to protect the appearances of its historical area.

Because of this, the not-for-profit station WBHF-AM (1450) was faced with some challenges when it moved its studio in 2003 from a corporate location outside of town to the bucolic historical district. The community fathers were all for a station that is big on the prep sports scene and local news, but they weren't too keen about the prospect of multiple four-foot-high satellite dishes being placed on top of the studio's building.

A combination of Digigram's off-the-shelf Ethersound audio bridges ES8in/ES8out and existing Ethernet that runs the four miles between the old facility and the new studio allowed the radio station to keep its dishes in place and keep the historical-minded community happy. Plus, the station saved costs by not installing the satellite dishes at the new site.

Performance at a glance

High-quality audio distribution Integrates into existing Ethernet Infrastructure Low latency: 125msec at 48kHz sampling rate 24-bit, 48kHz audio performance Reduces cabling needs Easy configuration

A tricky situation

We investigated several methods to carry the audio from the old location to the new studios, but each either required a higher ongoing cost or did not provide the reliability that we wanted. Because we had fiber running between the corporate building and the new station, we were able to install Digigram's Ethersound ES8in and ES8out using the existing Ethernet. We set up a virtual LAN, which dedicated 100Mb/s of bandwidth on the network. The five satellite dishes at the corporate office travel as streams through the system and break out on the studio end.

Ethersound ES8in injects eight analog balanced audio signals into an Ethersound network, while the Ethersound ES8out extracts eight analog audio signals out of an Ethersound network. The network set-up is as easy as plugging in an Ethernet cable. System set-up, control and re-configuration are operated remotely via straightforward PC software. No specific IT expertise is required. Applications include synchronous high-quality audio distribution in broadcast facilities, fixed installations and live sound.

One hitch I encountered is that Ethersound requires a dedicated network with the same bandwidth at all times. The Ethersound devices' identity is indicated by their MAC address, and a dedicated control software (EScontrol) is used to address, manage and control them. In our installation, we placed the terminals in an isolated portion of our network by creating a VLAN.

The way it is configured now, the system occupies 100Mb/s at all times, regardless of actual usage. It would be ideal if the system would dynamically occupy bandwidth as it is needed instead of holding a continuous chunk of the network. The advantages of the current method are the extremely low latency and that the bandwitdh is always available to Ethersound. There is no danger of the network being too busy to accomodate the audio demand when it arises.

And as WBHF AM-1450 found out, using Ethersound ES8in/ES8out and existing Ethernet kept our architecturally-minded neighbors pleased as well.

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Digigram
P F W E	703-875-9100 703-875-9161 www.digigram.com input@digigram.com

Ruzumna is chief engineer of WBHF.

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Editor's note: Field Reports are an exclusive Radio magazine feature for radio broadcasters. Each report is prepared by well-qualified staff at a radio station, production facility or consulting company.

These reports are performed by the industry, for the industry. Manufacturer support is limited to providing loan equipment and to aiding the author if requested.

It is the responsibility of Radio magazine to publish the results of any device tested, positive or negative. No report should be considered an endorsement or disapproval by Radio magazine.

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