Tuesday, July 24, 2012

Is military's communications system interfering with garage doors?

Blog Editor Note: This has been a very common occurence since DoD stood up their 380-399.9 MHz LMR subband. Back in 2003, I first documented the garage door interefence vs DoD trunk LMR system in my Monitoring Times Milcom column at Eglin AFB, Fl. When I called the PAO at Eglin and asked about what was causing the problem, they released a statement to me that they had just stood up a new 380-399.9 trunked radio system on their base. In my June 2004 Milcom column, I finally uncovered the paper trail on these new DoD LMR system:

"In a Deputy Secretary of Defense memorandum date August 1, 2001, the various military departments were given specific guidance regarding the purchase of equipment for Land Mobile Radio (LMR) Systems. This memo addressed the existing mandates set down in the NTIA Redbook regarding the change to narrowband technologies between 2005-2008 (see our April 2004 Milcom column in MT).

"But there was also an interesting mention of another LMR allocation in the 225-400 MHz band.

“In addition, new LMR radios or services procured after the promulgation date of this memorandum (1 Aug 2001-LVH) that operate in the 380-399.9 MHz band (which is not subject to the NTIA mandate) shall nevertheless be designed for narrowband (12.5 kHz) operation in order to make efficient use of the available spectrum.”

"So apparently what we have here is a hidden LMR band that has been created by the Department of Defense for use by the military only."

So the hits keep on coming as illustrated in the article below from the Stars and Stripes website. Story By Jennifer McDermott, The Day, New London, Conn.

MONTVILLE, Conn. — Sondra Tuchman used to open her garage door from halfway down the block. Now she has to get out of her car, stand in front of the door and press the remote. Sometimes she gives up and just walks through a side door.

On Thursday, Tuchman and a neighbor in the Hillcrest senior retirement community collected the signatures of about 50 people in their Uncasville neighborhood who said their garage doors also weren't working.

Tuchman said a salesman from Overhead Door Company of Norwich, Inc. told her the company had received similar complaints from customers in Groton, New London, Waterford, Montville and Gales Ferry. The company referred questions about the problem to the corporate office, saying that its equipment was not defective.

Rather, a new radio system operating at the Naval Submarine Base in Groton may be to blame. Known as Enterprise Land Mobile Radio, the communications system is being used at most U.S. military installations to connect military personnel and civilian first responders over a wide area, and it "may interfere with nearby garage door openers in the surrounding community," said base spokesman Chris Zendan.

The base began using the system in July 2011. ELMR uses radio frequencies between 380 and 399.9 megahertz, which have been reserved for the Department of Defense since World War II for air and ground communications but have been underutilized until now.

Some radio-controlled garage door openers operate legally at very low power on the same frequencies but are not licensed to do so. Because they are unlicensed devices, the owner/operator has no right to protection from interference.

"In response to the increased needs of homeland security, the Department of Defense now must make more use of these frequencies to deploy new mobile radio systems on and around certain military bases," the Federal Communications Commission said in a public notice. "Some consumers near these bases may experience interference to their garage door openers that can reduce operating range or cause the remote control to cease functioning."

Residents in communities near military bases across the country, from Eglin Air Force Base in Florida to the Marine Corps Base Quantico in Virginia and Naval Station Newport in Rhode Island, have reported jammed garage doors. The Providence Journal reported in May 2011 that a public relations consultant for Warwick's Overhead Door Co. said the company ordered replacement parts and will install them for free.

The commander of the Groton submarine base can't modify the system because of complaints from local residents or offer any compensation to those affected, Zendan said. The base has only heard from one other person complaining of a possible interference issue — in December 2011, he added.

Tuchman said she was told by Overhead Door Company she would have to pay about $300 to change her system to another frequency. A manager at the company told a reporter that replacing the equipment is "not our responsibility" because "it all has to do with homeland security."