We're putting together a little an FM station and I am trying to figure how to determine what kind of filter we need and how many cavities.
Some details: Our transmitter power output will be about 900 watts. At the site is an existing FM station 1kW ERP, their station has three transmitters each about 450 watts TPO feeding three antennas. All working together on the same frequency for a directional pattern. With their system they are using 3 Shively Labs VLP Bandpass Filter model 2914-4. No other full-power FM are at the site. There are two translators but they are at the opposite end of the FM band. Our station too is at the other end of the FM band.
Also at the compound is some cellular, two way paging, and microwaves but those are on other towers between 75 feet and 250 feet away approximately.
I talked to an engineer friend of mine and he said that a filter might not be needed because we will using a new transmitter and he said they are good at preventing 2nd 3rd 4th etc... harmonic interference.
My question is, how do you determine how many cavity filter you need when you are building a new station?
Some details: Our transmitter power output will be about 900 watts. At the site is an existing FM station 1kW ERP, their station has three transmitters each about 450 watts TPO feeding three antennas. All working together on the same frequency for a directional pattern. With their system they are using 3 Shively Labs VLP Bandpass Filter model 2914-4. No other full-power FM are at the site. There are two translators but they are at the opposite end of the FM band. Our station too is at the other end of the FM band.
Also at the compound is some cellular, two way paging, and microwaves but those are on other towers between 75 feet and 250 feet away approximately.
I talked to an engineer friend of mine and he said that a filter might not be needed because we will using a new transmitter and he said they are good at preventing 2nd 3rd 4th etc... harmonic interference.
My question is, how do you determine how many cavity filter you need when you are building a new station?