How can you extend the range of baby monitors?

Answer 1

First, consider an upgrade. Older monitors used 54mhz 5 watt transmitters that had limited range. Newer monitors use the 800-900 mhz band, which have better range, but can run into interference from cordless phones and other wireless devices.

The simplest way to improve the range of radio frequency (RF) devices is to focus and aim the signal. Search YouTube for 'cheap wifi signal booster' and you'll see dozens of tips for creating parabolic and half-cylinder shapes out of foil. These solutions are typically aimed at wifi routers, but the principle will work just as well for baby monitors. If your monitor does not have an external antenna, just place the base in front of the parabola/half cylinder and aim it in the general direction of the receiver.

To get around interference or obstructions like steel framework, block walls, or foil insulation, you could chain two monitors together to get around the obstacle. By chain, I mean place the receiver of the first unit next to the base of the second unit. (This has obvious drawbacks, but it worked for us.)

If you are handy and don't mind voiding your warranty, you could crack open the base unit and extend the antenna. To get the best performance, your antenna will need to be the proper length. You'll need to know the frequency (e.g. 900mhz) in order to determine the length of the antenna. The wavelength of a 900mhz signal is 33cm. Optimal antenna lengths are 1, 1/2 or 1/4 the wavelength. A practical 1/4 wave antenna for a 900mhz baby monitor would be 8.25cm.

The good news is that external 900mhz antennas are common and you can buy one in the $10-$60 range. (I'd go cheap if for this project.) To get around obstructions, you can run a cable between the base and the antenna, but the more cable you use, the greater your loss of signal will be.