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MaxxCasting Solves WIIL’s Milwaukee Problem

Getting the most out of your contour

MaxxCasting antennas can be mounted on cellphone towers.

Recently, Alpha Media’s WIIL(FM) in southern Wisconsin experimented with GeoBroadcast Solutions’ MaxxCasting Technology to solve the problem of improving its signal penetration into Milwaukee. We talked with

Bert Goldman, president of Goldman Engineering Management, the contract engineering firm that took on the task.

Radio World: Set the scene on what the problem was.
Bert Goldman: With respect to MaxxCasting, the problem is that especially in urban environments, many stations have difficulty covering their entire service area with a solid listenable signal. There are many reasons for this. Some markets have areas where terrain or urban canyons block an area which is within the protected contour, and some simply have signal strength problems at the edge of their coverage area. This is particularly true of Class B stations in crowded urban markets. The challenge has been to develop a system by which the coverage can be augmented to allow mobile signal improvement and in-building coverage where the signal from the main transmitter is poor without causing objectionable interference which could negate the improvement.

Specifically, with respect to WIIL’s signal in Milwaukee, the most populated downtown areas of Milwaukee are at the very edge of the 54 dBu contour. The station had marginal mobile signal quality and virtually no in-building signal.

RW: What criteria were considered — e.g. costs, labor, equipment, time, etc.?
Goldman: The costs can vary significantly depending on what equipment is used. At its most basic, each MaxxCasting node uses a GatesAir Intraplex IP Link 200 with built-in Intraplex SynchroCast technology, and a GatesAir Flexiva transmitter with (typically) a custom log-periodic antenna from Shively. In addition, there are lease costs for the tower site(s), as well as high-speed data required at each site either via landline or microwave for the data containing programming. To develop the system, it takes many hours of field measurement and propagation analysis, IP network design, FCC allocation and licensing work, antenna design, timing design, final installation and adjustment. The development and installation can far exceed the costs of the hardware, however, the development costs and often the hardware, installation, data, and tower lease costs are all rolled into a monthly licensing fee thus minimizing capital outlay.

The GatesAir IP Link and Flexiva transmitters for a MaxxCasting node.

RW: Did the MaxxCasting system solve the problem?
Goldman: Based upon my evaluation of the signal, which I evaluated both inside buildings and in an automobile, the MaxxCasting implementation in Milwaukee provided significant improvement not only in the downtown area, but also along the highly traveled I-94 corridor. While I could sense a transition (mostly by watching the RDS change on the radio) it was as seamless as I could imagine. There was no location where I would expect a listener would abandon the station. Ironically, as good as this was, the system was actually designed to test the GeoBroadcast Solutions ZoneCasting system, so the node placement and antenna design was not optimized for MaxxCasting. Still, the execution was excellent and the signal in the southern Milwaukee area was drastically improved.

RW: How did it solve the problem/perform as expected?
Goldman: The consensus, not just from me but from the staff at WIIL, was that there was a significant audience increase as reported by Nielsen. As important as general listenership is the fact that increased signal strength provides improved PPM response and that translates into better ratings. Performance was excellent. I personally listened to the difference in both an automobile and inside a building. Where there was no listenable in-building signal prior to the MaxxCasting node operation, the signal penetration was excellent after the node was turned on. Even in an automobile, where the signal was spotty and multipath-laden prior to the MaxxCasting system operation, when the node was turned on, the signal became solid. The automobile signal which appeared to be blended to mono on the automobile receiver prior to the MaxxCasting system was clearly in full stereo when the system was engaged.

RW: What was required to install/build each node?
Goldman: In most applications, it is necessary to license each MaxxCasting node as a booster with the FCC. In the case of the WIIL system, the MaxxCasting system is a subset of the ZoneCasting system. WIIL has Special Temporary Authorization from the FCC to operate the ZoneCasting system. When not splitting into zones, the MaxxCasting system is operating. It is expected that after the STA is complete, we will be modifying the nodes and filing for permanent boosters with the FCC.

As I mentioned, before we can install the first node, a significant amount of modeling, site acquisition, IP network design and installation must take place. After the infrastructure is in place, the actual construction is relatively straightforward. It consists primarily of an Intraplex IP Link codec with SynchroCast, a directional antenna designed by modeling with GBS’ software algorithms, and a Flexiva transmitter, the size of which is dependent on the node size and allocation criteria. Typically, to tightly control the signal and manage the interference area, the maximum signal ERP for MaxxCasting is under 1 kW. Once the hardware is in place, the node must be set-up, synchronizing modulation, timing and other parameters. Finally, there is a somewhat tedious process of fine-tuning the system to maximize the quality and minimize any interference effects. This takes at least one to two days per node and can take longer.

MaxxCasting antennas here are placed on an urban rooftop.

RW: Are there any downsides?
Goldman: It is inevitable that there are some areas where the real-time synchronization cannot be perfectly aligned. This is because we are trying to synchronize FM signals that are propagating at the speed of light, and aligning signals identically over the entire coverage area is contrary to the laws of physics. That being said, however, by tightly predicting and controlling where the signal goes and refining the synchronization of the parameters that we can control, huge strides have been taken in the last couple years in minimizing any negative effect on receivers in the field.

RW: Does this system require any monitoring or modifications or is it set-and-forget?
Goldman: We’re not sure exactly why, but it appears that the systems needs periodic monitoring and possible adjustment. I would say that in addition to simply monitoring the parameters to insure that the levels and timing are consistent, about once a year, it’s a good idea to go through the fine-tuning process to make sure that nothing has changed in the environment to adversely affect the operation.

RW: Will more nodes be built for the station in any other problem areas?
Goldman: While we will likely re-engineer the system for full-time MaxxCasting operation, I doubt that additional nodes will be necessary to cover the areas now receiving benefit from the MaxxCasting system, however, it may be advisable to move one or two. We haven’t focused on other areas yet.