Field Report: Broadcast Electronics FXi 60

For several years we have been preparing our Class C, country music station for digital operation. Broadcast Electronics' new digital exciter was on the list of equipment needed to complete WIBW-FM's digital audio chain — someday. Our reliable, ever-ready Broadcast Electronics FX-50 analog exciter had many years left of service and we were in no rush to replace it. Then, we received notice that a new station in Lee's Summit, MO, was willing to pay us to relocate WIBW-FM to a new frequency.

With a frequency change on the horizon, we were suddenly anxious to find out how fast we could get the new Broadcast Electronics FXi 60W exciter and how it would benefit the station.

Performance at a glance
Direct-to-channel modulation
Multiple input options
Smart buttons
Large screen display
On-screen troubleshooting
IBOC upgradeable
RBDS and SCA generators
Internal audio processing

Would it give us the same reliability as our trusty analog Broadcast Electronics exciter, only with the benefits of digital? In an effort to get WIBW to stand out and to get listeners to stop at its new position on the dial, the station's priority became audio improvement. Just about any digital exciter we chose would give us marginal improvement in the quality of the audio by eliminating the analog-to-digital conversion between our existing analog exciter and a digital STL receiver. The FXi, however, promised to give us something extra. Available in 60W and 250W, the FXi is a direct-to-channel digital FM exciter that converts the digital signal to the carrier frequency directly. Analog up-conversion (stepping through a series of oscillators and mixing to generate a desired frequency) doesn't exist in this exciter, which can only mean less noise, fewer spurious emissions and virtually no filtering artifacts.

My immediate concern was getting the unit by Sept. 17, when WIBW would move down the dial from 97.3MHz to 94.5MHz. We not only received the unit in time for the switchover, but we also received a visit from a Broadcast Electronics technician who came out to retune our existing Broadcast Electronics FM-35T transmitter and FX-50 exciter for backup.

Installation of the FXi 60 at our transmitter site went well, which was a pleasant surprise given that the unit we received was one of the first off the factory floor. The unit offered a smorgasbord of input options, which was extremely helpful in the short term because we were still operating off of our analog STL system but anticipating installing a new digital STL system in the coming months. The FXi 60 accepts AES/EBU, wired or optical, left and right analog, balanced and unbalanced composite or mono inputs. And, it can switch from a primary input to a backup input automatically. For the time being, we fed it a composite analog signal from our existing analog STL receiver. When the time comes to install a digital STL, we'll set up the exciter to take digital audio from the main STL and analog audio from the backup STL unit. That way, if the main digital STL receiver fails, the FXi 60 will automatically switch to analog audio input for the analog backup STL with no loss of service.

A Swiss Army knife

Once we got the unit installed and running, we checked the spectrum with a spectrum analyzer and everything checked out legal. Next, we decided to push a few buttons. This exciter has a lot more features than I'd come to expect of an exciter. The 4RU box includes an exciter, stereo generator, RBDS encoder, two SCA generators and audio processing — a broadcaster's Swiss Army knife. We plan to put all those functions to good use, with the possible exception of the stereo generator because we already have a stereo generator at the studio. We set up the two SCA channels for queuing purposes, and will set up the RBDS port at a later date.

I was curious how Broadcast Electronics solved the inevitable user-control overload for all the functions of the unit. The company earned major points from us in this regard. A good-sized screen display on the front of the unit offers several menu options selectable according to “smart buttons.” The smart buttons, along the bottom and side of the 640×480 display, change function from screen-to-screen so although there was ample user control, there was little confusion. This unit also has an on-screen troubleshooting guide that comes about as close as anything to automating the chief engineer. Once, when I was conducting modulation measurements of the main carrier, a pop-up box appeared on the unit's menu display reminding me that I needed to turn off an SCA channel first.

Overall, I found this unit to be user friendly and, more important, spectrally clean. (S/N ratio: 90dB below rated power reference carrier with 100 percent FM modulation at 400Hz, 75µsec de-emphasis with no FM modulation present.) If the station's stereo generator goes out, I can simply pull the FXi 60 offline as an exciter, plug in the backup FX 50 exciter and use the FXi 60 as a stereo generator. Because the FXi 60 can be upgraded to transmit IBOC with the addition of a card, we'll already have the exciter we need when the day comes to add IBOC to our facility.

O'Donnell is chief engineer of WIBW-FM/AM, Topeka, KS.

Broadcast Electronics

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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