FREQUENCY COORDINATION

The need for proper RF coordination is becoming more critical by the day. As the FCC continues to sell off UHF spectrum, white space devices
and other low power auxiliary units will become more spectrally

congested with one another. Soon, we will be down to

less than 10% of the radio spectrum that we’ve had since 1962.

Let’s dive into the reasons why proper RF coordination is

important and even mandatory, especially on larger scales.

Avoiding Intermodulation Distortion

Coordinating your transmitters will help avoid intermodulation.

“What causes intermodulation” you may ask? Wireless transmitters interact with one another. When they're too close, they will combine to occupy and create additional frequencies at defined intervals. In a simple form, wireless frequency coordination is a method for calculating these additional frequencies so they may be avoided. Two transmitted frequencies will introduce intermodulation products above

and below their center frequency.

For example:

522.000 MHz to 523.000 MHz

Spacing = 1.000 MHz

Intermodulation products will occur between

521.000 - 524.000. You can see these results below.

TV Stations

It is important to avoid UHF TV bands (currently channel 14 to 51 in the USA and 21 to 59 in Europe). Every location has different occupied channels, and it is imperative to coordinate around these TV stations. This will help you keep your transmitters operating on legal frequencies and avoid signal dropout. When a transmit frequency is placed on top of a DTV frequency, the signal to noise ratio falls considerably and you will likely experience dropouts and erratic performance. Here is a snapshot that shows new DTV activity in their area, causing issues for one of their frequencies. This scenario will become more prevalent as the DTV process and other spectrum sales continue nationwide. All the more reason to continuously monitor spectrum

conditions in your area and stay on top of changes.

Multiple Spectrum Stakeholders

When entering a area with multiple vendors bringing their own

transmitters, it is imperative to communicate with them to avoid

potential interference. A simple email or phone call prior to

arriving at the area can reduce a multitude of issues. Sharing

coordination files, or assigning one person to coordinate for all the

individual vendors are a few safe practices. Be transparent, and

update each other as changes are needed to be made. A lot of wireless

users get by just turning on their receiver to see if it’s on a clear

channel (no RF showing on any other equipment). Often you

can get, by just using this method, a few frequencies for use.

However, by following some simple guidelines and communicating

with other spectrum stakeholders, your results will be much

better in the end. This is especially the case in high channel count

RF projects, like schools or congested population

areas, or high use spectrum conditions.

To check what your spectrum looks like, CLICK HERE and enter your zip code and it will give you a great idea of what is going on in your area.

FOR MORE INFORMATION:

PLEASE EMAIL: [email protected]

526 W MAIN STREET, GALLATIN, TN 37066

(615) 98-0725

AREAS WE SERVE: SAFETY / SECURITY / LE / HOBBYISTS / AMATUER RADIOSISTS / BUSINESS RADIO / SCHOOLS / HIGHER EDUCATION / CLUBS / 501C3'S / SPORTS / AUDIO / VISUAL / THEATRE / CLUBS / MOTORCYCLISTS/ CHURCHES