LPFM Checklist: Antenna Structures
In LPFM, our antenna sites can vary from rooftops, backyard towers, even in trees all the way to the large commercial leased sites and mountain sites. While you may not necessarily own the structure that your station’s antenna is mounted on, all stations should review these guidelines. Some may not apply to your specific situation but let’s go through them.
Antenna Structure Registration
Most antenna structures that are higher than 200 feet (60.96 meters) above ground level or that may interfere with the flight path of a nearby airport must be studied by the FAA and the FCC. Owners are required to register their non-exempt tower structures with the FCC. All proposed and altered antenna structures must be registered before a new construction permit or license modification involving the tower or antenna is granted.
Licensees should be familiar with the painting and lighting specifications shown on their station authorization. In the event the structure owner is unable to maintain the prescribed painting and lighting e.g. in cases including but not limited to abandonment, negligence or bankruptcy, the FCC requires each tenant licensee on the structure undertake efforts to maintain painting and/or lighting. Additionally, if the licensee has reason to believe the structure is not in compliance or that the owner is not carrying out its responsibility to maintain the structure, the licensee must immediately notify the owner, notify the site management company (if applicable), notify the FCC, and make a diligent effort to ensure that the antenna structure is brought into compliance.
Once a tower is registered, a registration number is to be displayed in a conspicuous place that is readily visible near the base of the antenna structure. When the tower is located where the number cannot be seen without access to the property on which it is located, then the number should also be placed on the gate or fence leading to the tower where an outside observer can see it. Materials used to display the registration number must be weather-resistant and of sufficient size to be easily seen.
The FCC Antenna Structure Registration system can be found at http://wireless.fcc.gov/antenna/.
The construction permit, station license or other instrument of authorization provides authority for the station to operate under a specific set of operating parameters. The licensee must thoroughly review the current station authorization, and, where applicable, the structure registration, to compare the listed specifications to the location, height, etc. that is actually used by the station. All LPFM stations may utilize non-directional antennas with horizontal, vertical, circular or elliptical polarization. Directional antennas will only be authorized to eligible public safety and transportation licensees in connection with a travelers information service or when necessary, in connection with a waiver of the second-adjacent channel spacing requirements.
Tower Light Observations
The lighting on tower structures is to be observed at least once every 24 hours either visually or by observing an automatic indicating device; or alternatively, the licensee/tower owner may provide and maintain an automatic alarm system to constantly monitor the lighting on a structure. All automatic or mechanical control devices, indicators and alarm systems are required to be inspected at intervals not the exceed 3 months.
The station authorization and/or tower registration specifies the painting and lighting requirements for an antenna structure. This is shown as a set of numbers or letters which correspond to paragraphs found on FCC Form 715 (Numbers – For towers with red beacons and side lights) or Form 715A (Letters – For towers with strobed lighting), or the most current FAA Advisory Circular (which is currently AC 70/7460-1L Obstruction Marking and Lighting). If no painting or lighting is required, then the authorization will specify “NONE” or “NONE REQUIRED”. Tower registration is only necessary when painting and/or lighting is required.
The licensee must make certain that the number and placement of paint bands and lighting match exactly with that shown on the station authorization and/or tower registration. The licensee/tower owner should be aware of the requirement to clean or repaint the tower structures as often as necessary to maintain good visibility to aircraft.
One of the most common problems associated with tower painting is the feedlines that are on the outside of the tower. In many cases, the tower is painted correctly, but the solid black feedlines defeat the purpose of painting by covering the outside faces of the tower. The licensee/tower owner should make certain that the feedlines are also painted in such instances. This does not apply in cases where the tower is authorized for strobe lighting.
The tower owner/licensee is not notify the Federal Aviation Administration at 1-877-487-6867 within 30 minutes of the observation of an improper functioning or extinguished top steady burning light or any flashing obstruction light regardless of its position on the structure. Such improper functioning beacons include non-lighted beacons as well as those that are lighted, but not flashing. Notification is also to be made immediately to the FAA once the beacon or steady burning light is returned to service. Notification is not required when side light outages are observed. Tower owners/licensees should insure that the telephone number for the FAA is readily available and known to all personnel who would be responsible for notifying the FAA of such outages.
For all stations operating from a tower owned by the licensee and which have authorizations that specify tower lighting, the licensee/tower owner is to make entries in the station log concerning any observed or otherwise known extinguishment of improper functioning or any tower light regardless of its position on the tower. The log must contain the following:
- The nature of such extinguishment or improper functioning.
- The date and time the extinguishment or improper operation was observed or otherwise noted.
- Date and time of FAA notification, required for outages or any flashing light.
- The date, time and nature of adjustments, repairs or replacements made. This would include any work conducted as part of a system inspection or preventative maintenance program.
- Licenses should also log the date and time of quarterly inspections of lighting systems as described in §17.47(b) of the rules.
Any extinguishment or improper functioning of a required tower light, regardless of its position on the tower, is to be corrected as soon as possible. See §17.49(b) and the terms of the structure registration. An antenna structure is not considered to be in compliance with the antenna structure registration if any required light is not functioning properly. However, violations are avoided by prompt and complete logging of the outage and documenting that the efforts made to correct the condition are being done in a timely manner.
(Items with an asterisk * may not apply to all stations)
For all LPFM stations:
- Does the overall height of the structure match that specified in the station authorization and, where applicable, the structure registration?
- Is a non-directional antenna in use at the station?*
- Does the street address and geographic coordinates of the station transmitter/tower location match exactly with the information shown on the station authorization and, where applicable, the structure registration?
For LPFM stations on registered tower sites:
- Has the owner of the tower on which the station antenna is mounted obtained registration for the structure?*
- Has the registration number been posted in an easily viewed location at the tower site? *
For LPFM stations on towers with painting and/or lighting requirements:
- Does the painting on the tower structure match the specifications on the station authorization? *
- Does the structure have the correct number of bands with the top and bottom bands painted orange? *
- Does the lighting on the tower structure match exactly with the specifications in the authorization?*
- Are the tower owner/licensee and all station operators aware of the requirement to notify the FAA within 30 minutes of the observation of an outage AND to notify the FAA again once the outage is corrected?*
- FCC Rules Part 17 – Construction, marking and lighting of antenna structures
- FAA Advisory Circular AC 70/7460-1L – Obstruction Marking and Lighting
- §73.816 – Antennas (LPFM)
- §73.877 – Station logs for LPFM stations
- §73.1231 – Antenna structure, marking and lighting
Related REC Knowledge Base Questions and Answers
- What information must be kept in the station log?
- The CP shows only a horizontal power but no vertical power. Does this mean that LPFM is prohibited from using vertically polarized antennas?
Before you go, feel free to download a two-page version of the checklist items suitable for use at your station.
Information in this document is current as of September 29, 2016.
Information provided by REC Networks is for educational purposes only and should not be construed as legal advice. For legal advice, please obtain the services of a qualified attorney that specializes in FCC law, especially where it comes to LPFM.