Channel Search Results

Whenever the Search to a New Location or the Check for Alternate Channels Search is ran, the result will be the Channel Search as described below.

Feature Availability

Feature	REC Clients with $350 minimum spend	All other myLPFM users
Identification of available channels
Identification of channels with potential interference
Identification of potentially interfering stations
Check for nearby airports
Check for nearby AM towers
Channel Reject Report

Channel Search header

When you first run a Channel Search, you will see a header that will look something like this:

• Reference ID - This is a unique identifier for the search result. You may refer to this ID when discussing the application with REC Networks.
• Last Updated - Previous channel search results are cached. This indicates when that search was performed. If a long time has passed since the last run of this site, you can refresh the search by clicking on Update Results
• NAD83 Latitude & Longitude - The geographic coordinates of the site being checked.
• Elevation - The elevation at this site in meters and feet.
• Terrain Data - The terrain database that was used for the search. Currently, myLPFM uses GLOBE 30 second terrain data for all searches.
• Ant Height - This will start at ground level. You can set an antenna height above ground by using the procedure mentioned below.
• HAAT - This is the height above average terrain (HAAT) at the antenna height shown (defaults to gound level until an antenna height is set).
• Min ERP & Max ERP - These values will be set once an antenna height is selected.

FCC limits on minor modifications

The FCC has limits to what is considered a minor modification that can be filed at any time outside of a filing window.

Channel of operation

In order to be considered a minor change, the channel at the new site must be either the same channel that the LPFM station is operating on right now or can be 1, 2, 3, 53 or 54 channels away (+/- 0.2, 0.4, 0.6, 10.6 or 10.8 MHz).

Any of the 100 FM channels can be considered if a showing can be made where the station will either receive or give less interference on the new channel and a full technical showing is made to demonstrate that.

At this time, myLPFM will identify the available channels that do and do not require a technical study.

New station location

The FCC will allow an LPFM station to be moved up to 11.2 kilometers away (assuming there are channels available). The Channel Search Result will show the distance from the current to the proposed site and provide an indicator on whether the change will be allowed.

The FCC will allow moves of over 11.2 kilometers only if it can be shown through a contour study that the 60 dBu service contour of the current LPFM facility and the 60 dBu contour of the proposed facility overlap. In these cases, in the Minor move field, it will display Build facility to verify overlap. Clicking on that link will bring up the Site Details screen where you can indicate the antenna height details (see the next section for more details). Once the information is entered, the Minor move field will indicate whether a move is available because there is contour overlap or it is not available due to a lack of overlap.

Entry of antenna height

In order to determine the proper HAAT and effective radiated power (ERP), you will need to tell myLPFM how high the antenna is going to be by clicking on Click here to add tower/antenna height details for ERP & other information. This will take you to the Site Details screen.

Site Details screen

On this screen you will need to first select the tower arrangement by clicking on the applicable tower diagram:

• Standalone tower - The tower is free standing, either with or without guy wires. It does not touch a structure.
• Adjacent to building - The tower base is at ground level but the tower is directly adjacent to a structure.
• On roof of building - The base of the tower is on the roof of the structure.

Once you have the tower type selected, then you will need to enter heights as follows:

• Support Structure Height - Used only if the second (adjacent to building) or third (on roof of building) options are chosen. In both cases, this is the distance from ground level to the highest point of the roof of the structure.
• Tower Height Above Attached Structure - For towers that are adjacent to buildings or on the roof, it is the height measured from the highest point of the structure to the highest point of the tower structure (for example if a building is 6 meters tall and the tower is 14 meters, this value would be 8). For towers with no structures (first option), this is the overall height of the tower.
• Radiation Center - This is the height from ground level to the radiation center of the antenna. The height of the radiation center may vary by antenna. Please contact your antenna manufacturer to determine where this point is for your antenna system. Usually, for a single bay antenna, it is the point of the middle of the antenna when measured vertically and for two bay antennas, it is the point directly between the highest and lowest points of the antenna when measured vertically. The diagrams on the tool give examples for these antenna types.

If you know the feet, but not the meters, you can enter the feet and then click the [ft to m] button for the appropriate entry and myLPFM will convert the feet into meters.

When all information is entered, click on [Update Facility] and you will return to the Channel Search Result.

Channel Search header with site details

The Channel Search Result header will now return with additional information:

You will now see that the HAAT has changed to the actual HAAT for that radiation center. You will also now see the maximum and minimum effective radiated power (ERP) for that radiation center. Normally, this is 100 watts maximum and 50 watts minimum however, if the radiation center is more than 30 meters HAAT, then these values will be reduced in order to make a service contour of 5.6 kilometers as per § 73.811 of the FCC Rules.

Tower Registration due to nearby airports

If because of the height of the tower, there is the possibility that the tower would need to be registered with the FAA if the result after 'FAA Tower Registration' shows Required. Tower registration is not required if the structure already has an Antenna Structure Registration Number and the proposed construction does not change the overall height of the tower.

For details on checking for nearby airports to proposed LPFM sites, see our Runway Slope Help Page.

Notifications to AM stations

If the proposed tower is within 3 km of an AM broadcast station tower, myLPFM conducts a study to check to determine if the proposed tower could have an impact on the performance of an AM station. If a potential issue is identified, the value in 'Notification to AM Stations' will show Required. If you get that message, click on that Required link for more details.

For details on checking for operation near AM towers, see our AM Check Help Page.

Potentially Available Channels

The list of available channels is divided into two categories. The first section shows channels that have an 'adjacent' channel relationship (+/- 1, 2, 3, 53 or 54 channels or +/- 0.2, 0.4, 0.6, 10.6 or 10.8 MHz). A change can be made to those channels without the need of a technical study demonstrating reduced interference. The second list is for 'non-adjacent' channels. If a change is made to one of those channels, § 73.870(a) of the FCC Rules requires that the application include a technical study that shows that interference will be reduced. This is normally demonstrated by showing that the interfering F(50,10) contours of other co-channel and first-adjacent (+/- 0.2 MHz) channels arriving at the LPFM station site are weaker than the interfering contours arriving at the current site and channel, thus meaning a reduction in interference.

Color Code of Available Channels

For quick reference, each available channel is identified by a color background.

Green	This channel meets the FCC recommended distance for not receiving any incoming interference on co- and first-adjacent channels.
Purple	This channel meets the FCC recommended distance for not receiving any incoming interference on co- and first-adjacent channels. It does not meet the requirements for second-adjacent channel spacing and therefore a waiver request would be required upon a showing of no interference.
Yellow	This channel does not meet the FCC recommended distance for not receiving any incoming interference on co- and first-adjacent channels and may be subject to incoming interference.
Orange	This channel does not meet the FCC recommended distance for not receiving any incoming interference on co- and first-adjacent channels and may be subject to incoming interference. It does not meet the requirements for second-adjacent channel spacing and therefore a waiver request would be required upon a showing of no interference.

Other Advisory Messages

On each channel returned as potentially available, you may also see one or more advisory messages about the channel:

HD Hijack

HD Radio involves the use of 'sidebands' outside of the normal audio bandwidth for an FM broadcast signal to carry digital programming. Those sidebands can sometimes be received in areas where there is another stronger local station located. As a result, listeners using an analog (non-HD) radio will receive the desired station. Those with HD Radios may not receive the desired (LPFM) station, but may instead receive the distant HD station.

If a 'Possible Inward Interference' advisory is given and if the station that is potentially interfering is also reported to be a HD station, this advisory will appear. REC Clients will also see the call sign of the potential HD Hijack station.

See a graphical representation of HD Hijack

Super-power Stations

Prior to 1962, FM stations did not operate at the ERP and HAAT limitations that we have in our modern day service classes (A, B, C3, etc.). As a result, these stations were 'grandfathered' at those higher powers and heights. In the non-reserved band (Channels 221~300, 92.1~107.9 MHz), these super-power stations are protected by LPFM stations only to their modern station class designation.

This advisory message will appear on a channel where there may be such a super powered station as a co-channel or first-adjacent channel station. REC Clients will see the call sign of the super powered station involved.

Short-spaced to Another LPFM

This message will appear in cases where the channel is only short-spaced to another LPFM station. An LPFM station may only use this channel if they are already in a time share agreement with the short-spaced LPFM station.

Short-spaced to TV Channel 6

On Channels 201~220 (88.1~91.9 MHz), & 73.825 requires that LPFM stations meet certain distance separation requirements in respect to full-service and low-power TV Channel 6 stations. The channel is only available if either the LPFM station has a statement from the short-spaced TV facility consenting to the short-spacing. The FCC will also accept a request for waiver if a contour study, using the procedure outlined in the FM translator rule § 74.1205 indicates that there is no overlap and that notification is sent to the short-spaced TV station to advise of the application.

Channel Reject Report

Clicking on the Channel Reject Report link will display all 100 FM channels and for those channels that are short-spaced, it will identify the short-spaced station (the reason why the channel is not available). For more information about the Channel Reject Report and its color codes, please view the Channel Reject Report Help Page.