Special Report: Wireless Interference Protections

Effect Of Registration

It’s most important to remember a fundamental concept about wireless mic users registering in the databases.

The wireless mic user is not reserving TV channels for his/her exclusive use; rather the registration has the effect of removing a TV channel from the pool of available channels for TVBDs.

Once one wireless mic user registers and reserves a TV channel, any wireless mic user within the protected contour has the protection of that channel. Nearby wireless mic users must still coordinate among themselves to avoid interference just as they’ve always done.

Whether a Part 15 or 74 user, the second point is to know where the venue is located in terms of latitude and longitude coordinates. Google Earth is a useful tool here as well as any GPS unit or GPS equipped phone that can display coordinates of a current location. All of the databases will accept coordinates to identify a location, but not every venue may have an address that accurately reflects the event location; think large parks, golf courses, road races, parades, private or abandoned airports.

Once the coordinates are determined, the user should go to the database of choice, to the query page. Entering the coordinates and the type of device (wireless microphone) will then return pertinent information based on the user’s location: The two reserved channels for wireless mic operations and channels available and unavailable for TVBDs based on type. From this information the user can then determine the optimum channels to use first and which channels (if necessary) to request for reservation.

Site Scan Needed

After the two reserved channels, it will be best to choose channels completely unavailable to TVBDS of all types but which spectrum is in fact quiet enough for use. In other words, the user will still need to perform a site scan of the RF spectrum upon arrival.

Next choice would likely be those channels which permit only 40 mW personal/portable or only fixed TVBDs at less than 3 meters height above average terrain (HAAT) if far enough away. There is currently discussion whether the databases will have the capability to return relevant information on fixed nodes so wireless mic users could determine their interference potential.

Should a Part 74 user determine additional channels are required, they will go directly to the database of choice, go to the registration page and complete the form. They will need to know the call sign of the associated license, provide contact information, a day and time schedule of operations, the coordinates of the event (either a single lat/lon pair or a group of coordinates to create a polygon of protected area) and the channels being reserved. Fields for additional authorized persons to update the registration as well as for the password will also be provided.

Once the registration is submitted, the channel reservation is immediate and all databases should be updated within about 10 minutes, presuming no errors in the submission. Changes, additions and subtractions of channel numbers, schedule, even venue, are permitted any time by any of the authorized persons.