There are a variety of security systems available on the market today, starting with the more traditional types that are more intrusion alarm-oriented and consisting of alarms and sensors rather than video cameras and monitors.

Combining more common intrusion alarm systems with video camera-based systems can be the best of both worlds.

There are even ways to view what the cameras are seeing through the use of "RF" signals sent by the cameras to a TV.

RF is nothing more than an abbreviation for "radio frequency," and most such systems make use of an RF modulator and also an RF splitter and combiner.

The modulator is the device by which the images seen by the camera can be decoded and then viewed through the television. The signal needs to be corrected, or "modulated," of course and then either split or combined into usable chunks for the benefit of the television.

As a way of seeing everything that's going on out in front of the cameras from the comfort of one's own living room and TV, an RF-equipped camera and a television can be a very elegant solution to the issue of needing a separate monitor and digital video recorder (DVR) in some instances.

RF can be an effective means of quickly establishing a linkup between cameras and their display accessories.

For those who don't know, RF is the means by which all kinds of wireless technologies communicate. This includes GPS, cordless phones, and radio and TV broadcasting.

Even Bluetooth and cell phones operate off RF technology. We know that radio waves move at the speed of light and we are completely surrounded by them at all times.

But frequency is a different story with RF.

This refers to the actual radio waves in RF, and they move slower than the light that's visible to the human eye, which means they'll be invisible, fortunately. If they weren't they'd most likely completely obscure everything because they'd be so numerous.

RF is measured by wavelength and is from 100km down to 1mm, which can yield a frequency of from 3 KHz (Kilohertz) up to 300 GHz (Gigahertz). Think of your favorite radio station and its place on the dial (maybe FM 88.7 MHz, or Megahertz).

That's the frequency (based on the wavelength broadcast by the station's transmitters) that one will "dial" into.

A security camera will broadcast on a specific wavelength frequency that its receiver at the other end will pick up, decode and then render an image from.

RF signals depend for their strength on their modulation boost. An RF camera sends a relatively week signal which is normally only received, at most, out to 1,000 feet (most can only reliably broadcast out to 100 feet).

For those systems that use wires to send that signal along, they must be of sufficient signal strength to overcome resistance present in the cable and because of having to move along a medium.

Radio interference in an RF system can be overcome by increasing the signal strength sent from the camera to the TV device equipped with a modulator and a splitter and combiner.

Those thinking of using RF cameras so that they can use their TVs as a monitoring device (on a channel the RF modulator will set up) should always make sure signal strength is sufficient to overcome distance or any spillover radio interference from other broadcast devices in the area.