As of September 2021, LP-250 (Low-Power FM with 250 watts of effective radiated power) was not a standard service class for LPFM stations. The FCC’s LPFM service classes included LP-100 (100 watts ERP) and LP-10 (10 watts ERP), but LP-250 was not among them.
As of September 2021, LP-250 (Low-Power FM with 250 watts of effective radiated power) was not a standard service class for LPFM stations. The FCC’s LPFM service classes included LP-100 (100 watts ERP) and LP-10 (10 watts ERP), but LP-250 was not among them.
Your station’s effective radiated power (ERP) for LPFM broadcasting is influenced by various factors, including your antenna system. Here’s a summary of how different antenna configurations can impact your ERP and transmitter power requirements:
- Single-Bay Antenna (e.g., Nicom BKG-77 or Shively 6812b):
- Antennas like these typically have a 3 dB loss.
- To achieve 100 watts ERP, you would need to transmit more than 200 watts from your transmitter.
- Two-Bay Antenna Arrangement:
- A two-bay antenna setup, among others, can provide approximately 0 dB gain.
- With this arrangement, you can transmit less power from your transmitter, allowing you to reach up to or close to 250 watts ERP from a 300-watt transmitter.
- Feedline and Equipment Losses:
- It’s essential to consider losses in your feedline and any equipment between the transmitter and the antenna, such as lightning arrestors.
- These losses can further affect the overall power requirements and efficiency of your broadcasting setup.
Optimizing your antenna system and understanding the losses associated with different components are crucial for achieving your desired ERP while efficiently utilizing your transmitter’s power output. It’s recommended to consult with a broadcast engineer or antenna specialist to design and configure your system for optimal performance.
Transitioning to a higher power level like LP-250 involves significant logistical challenges and considerations in your transmission plant. These factors will determine whether an upgrade to LP-250 is feasible for your station or if alternative options like finding a new transmitter site or channel are necessary to meet the higher power requirements.
It’s crucial to keep in mind that LP-250 is still in the proposal stage and has not been officially adopted by the FCC. There are no guarantees that it will be approved, as it has faced rejection in the past under different circumstances. However, your station’s determination to prepare for a potential LP-250 service is commendable. Just be aware that any infrastructure modifications made in anticipation of LP-250 are done at your own risk, given the uncertainty of its approval.
Staying informed about the progress of LP-250 and consulting with experts in broadcast engineering and FCC regulations will be essential as you consider potential upgrades and changes to your station’s infrastructure.