Base FM vs Swing FM

Complaint lodged 29/11/2010

Description of Interference: Swing FM has been running excessive power. We tried to contact him for the last 2 years, offered assistance. He confessed on the phone that he’s over-powered by refuses to meet up or turn it down.

Preliminary information

Base FM have been broadcasting on 107.3 for 7 years and is a well established station with loyal listenership. It broadcasts in mono with RDS subcarrier at 3.6KHz deviation. Its modulation is within spec.

Base FM deviation plot

Swing FM deviation plot

Bast FM coverage map at 54dBuV/m looks like this.

Base FM and Swing FM Coverage maps together looks like this

Looking at an interference plot of Base FM with Swing as the interfering station looks like this.

There is marginal interference (black area) of Base FM at 54dBuV/m based on this prediction. On the surface there appears to be very little reason that Base FM and Swing FM cannot co-exist on the same frequency. It is therefor my opinion that in order for Swing FM to impact on Base FM, as suggested, then Swing FM must be running at a greater power than Base FM. It is possible that because Base FM is optimally modulated vs Swings sub optimal modulationthat Swing FM believe Base FM is running at a higher power.

Further testing is required.

This will include

1) Power checks of Base and Swing FM

2) Empirical testing of the two stations to see if the coverage reflects the maps above (assistance would be useful)