The issue of 800 MHz interference continues to plague public-safety communications users — as it has for more than a decade — even as we enter a new year with fresh optimism. In addition to 800 MHz rebanding, which many public-safety agencies across the country are still addressing, new cellular rules proposed in 2014 threaten to bring more interference problems for public safety.

Here’s a quick summary. In November 2014, the FCC suggested amending its rules for cellular services. Specifically, the FCC proposed to supplement its existing effective radiated power (ERP) limits for the cellular service with alternative limits based on power spectral density (PSD).

The FCC requested comment last year but has not ruled on whether to officially adopt the PSD model. In the meantime, some public-safety agencies have experienced interference with commercial providers that are rolling out Long Term Evolution (LTE) technology.

This has spurred several ex parte filings with the FCC detailing the issues. The filings are from commercial providers, as well as the Association of Public-Safety Communications Officials (APCO) International, at least one public-safety communications official and an industry engineer. Sources said filings from several more public-safety users are expected soon. Click here for details on the filings.

As often happens, part of the problem seems to be different metrics and language used by the commercial industry vs. the public-safety communications community. PSD is not used as a measure of power output in the LMR industry, for example, and comparing apples to apples to address the interference issues is difficult in this situation.

With different suggested industry remedies and cellular carriers pushing forward with LTE deployments, 800 MHz interference is one headache that is not likely to go away in the new year. Let us know if you have 800 MHz interference issues and your thoughts on the proposals filed with the FCC in our comments section below.

---

Sandra Wendelken is editor of MissionCritical Communications and RadioResource International magazines. Contact her at swendelken@RRMediaGroup.com.