Operating Hardwired and Wireless Burglar and Fire Alarm systems In areas with high RF Power fields It can be done successfully

Operating Hardwired and Wireless Burglar and Fire Alarm systems

In areas with high RF Power fields

It can be done successfully

By Nick Markowitz Jr.

 

In our modern world it is getting tougher to operate with out having glitches and gremlins messing with electronic equipment do to the massive amount of RF –Radio Frequency signals in the air even the commercial office building is becoming a high RF usage area.

But electronic systems can work together and not bump into each other when proper precautions are taken to prevent them when doing the initial install.

In this article I will present two facilities I handle were very high RF fields are present and

How I have been able to allow systems to work together even wireless ones.

Case no 1# involves the 5000 Watt Praise 910 AM radio station I work at in Apollo Pa.

In this facility RF is always pounding, as our studios are located next to our transmitting towers .Yet a Wireless burglar alarm works with out problems as does the Phone system and other electronic systems in the building. The wireless burglar alarm even works outside the station building were it is protecting the tower gear buildings

At the base of the 2 towers from theft and vandalism.

It starts first with proper grounding and surge protection and using good quality equipment I chose the Ademco/Honeywell Vista 15P Panel which gives us a logging capability to know who is coming and going at the station to which I added various hardwired smoke and heat sensors for fire and motions glass break and door contacts.

I also added wireless receiver to pick up glass breakage in areas were it is almost impossible to get a wire in the station I continued by adding wireless shock and vibration sensor and door contacts on to the transmitter huts which are on a 24 hour loop so we know any time any one is messing around near the towers.

All wiring to the burg/fire panel at the station is done with Cat 5e wiring to help knock RFI out of the wiring and were the wiring enters the panel a AM filter check is snapped around the wiring bundle. Ac power o the panel is on a direct wired 20 amp circuit which also serves the phone system at the main breaker panel Delta Lightning Products and Wiremold industrial strength Surge /Lightning protection is installed and a Ditek plug in surge protector is used were the transformer provides power to the phone and alarm panel

Next the phone system and alarm are tied to a 10# solid copper ground which attaches directly to the grounding buss of the 400 amp service and a AM filter choke is also installed over the ground to prevent RF from entering the panels the panels are mounted directly to the concrete wall to also help ground them better and from building up a capacitive coupling effect from the RF onto the panels. The system operates well and only false alarms we had was when a 360-degree motion from Visonic failed. All of the

Motions and glass breaks etc were purchased based on their RFI resistance.

Which included Ademco/Honeywell, Visonic, System sensor and Intellesense Products.

Careful attention was also placed on the phone line as well by using Cat 5e wire and Ditek Phone Surge. As the alarm is also used to monitor various problems with the transmitting system such as tower lights out overheating transmitter etc. Which are sent to ATC Monitoring in Wheatland Pa. And directly to my Alpha Pager as well from the panel which gives me separate and distinct code info.

 

Case 2# Cloverleaf Tower Apartments.

One of my bigger customers purchased this group of 5 apartment buildings, in 1999 that includes 4 low rise and 1- 6-story tower building in Baldwin twp. Pa.

The 6 story apartment tower is unique in that it is one of the highest peaks in the south hills and many wireless users wanted to lease space on the roof for there repeaters and transmitters. XM Radio has a repeater on the roof along with Duquesne Light company who has a repeater on the roof which picks up signals from there clients electric meters which send usage amounts thru the air. And 3 cellular phone company's have there equipment on the roof as well which means in the basement of the building there are rooms filled with heavy duty electrical switch gear and massive amounts of digital phone line control units. All able to cause massive amounts of RFI, EMI interference.

So maintaining a Fire alarm in the building can be tricky when my friend bought the building it had an older Fire-lite Sensiscan 1000 fire panel in it with 24 volt dc bells and Detection Systems/ Bosch smoke detectors and as Radio equipment was added to the building problems stated developing with falses. To make matters worse the building has many elderly residents So not only did my customer want the falses stopped he wanted the building monitored. I started out by switching out the old Firelite panel with a new 5208 Silent Knight Fire Panel and then removing the old bells and installing a Faraday horn strobe on each floor I also switched out the old Edwards pull stations to easier to use Faraday pull stations as well and the old style Bosch smokes were replaced with ones from System sensor. Again extra precautions with solid grounding, surge protection and dedicated power line were followed along with phone line protection. The vast majority of the fire wiring is either in conduit or twisted pair fire wiring to keep RF transients at a minimum and the system has performed well. The silent knight panel had to be switched over from SK 4/2 format to Ademco Contact ID to overcome noise on the phone line when it was switched from standard electronic switching to digital but that has been the only major problem The 5208 also solved another problem as well because the fire dept can now get instant answers to the location of the alarm and silence and reset the panel from the lobby remote keypad station unlike the old system were they always had to make a trip to the basement maintenance room. I often get questions from phone company techs as to how my system is operating with out false alarms as they have seen many in other buildings were they have there wireless gear.

In both cases proper attention to grounding ,surge protection and using High FRI resistant equipment has paid off in the long run.