How to calculate the TPO

[Frankie26]

Can some one help me or calculate a TPO, I need to know, I'm using PSI FML-4 bays, 94 meters of Andrew 7/8 foam cable ANDAVA5-50, 6 feet MLR-400 Cable adapted to the transmitter BW Broadcast TX300 v3. attached a diagram with Andrew cable information.

To produce 250 watts ERP for station W222AL, what would be my TPO? some calculation please? I'll appreciate it.


Frankie

 

[frankberry]

I did some simple calculations using the information which you provided.
Your TPO would be 137 watts for an ERP of 250 watts.

Calculate Effective Radiated Power (ERP) from Antenna Gain and Transmitter Power

Calculate ERP (effective radiated power) from an RF transmitter in watts given antenna gain in dBd. Free online calculators.

www.antennas.ca

 

[Frankie26]

Thanks Frankerry,

Could show me your calculation so I can understand it? how much do you have for the antenna's bays, how much from the cable and explain why is 137, so I can calculate and have the idea. could you provide me the calculation?

 

[Frankie26]

Something like:

Transmitter Power Output:

The PSI FML-4 antenna has a power gain of .............

The 94 meters of Andrew 7/8 foam cable ANDAVA5-50 has a loss of........or efficiency of........

6 feet MLR-400 Cable adapted a loss of .1db

The total transmission line system has a total loss of ........ efficiency of .........

250 watts ERP divided by xx... divided by 0...... = ....... watts TPO.

 

[rfburns]

I looked at the modification filed for W222AL. It specifies a directional antenna. The antenna manufacturer has to furnish the antenna input power figure. Calculations for a non directional antenna system are pretty straightforward, but directional FM antennas are a whole different story.

 

[Greg Strickland]

Frankie26-

I am posting because translators are not permitted to cause interference to reception of other stations. It is wise to make sure a directional translator antenna is producing the authorized pattern.

The person who prepared the CP application engineering exhibit could assist you with preparing the license to cover application.

If you are concerned about the TPO value the person who prepared the exhibit, and PSI could help. I agree with rfburns, best to obtain antenna input power value from PSI, for the antenna you are authorized to construct.

 

[Frankie26]

Look the attached, is it correct?

 

[Frankie26]

PSI Provide the Antenna gain input it is 2.35 (3.71 db)

 

[Kelly A]

Look the attached, is it correct?

Did you even see RFBurn's comment? If a directional antenna is required, your TPO and ERP will not be determined the same way as a non-directional antenna.

 

[Frankie26]

What I think is the gain input of the antenna change based in the directional Patterns, my translator W235CN 94.9 in Providence used the same antenna's bays PSI FML-4 but the gain input is different since the patterns are different being both directional, what I used was the gain input of the W222AL patterns. All PSI FML-4 bays has different gain inputs depending of the Antenna Patterns. All other should be the same calculation.

 

[Frankie26]

Look attached 3 different patterns directional one is W235CN 94.9 and below W222AL both are directional, but use same antenna model but the input gain are different. if would be omni it also shows another different gain input. I think the patterns determinate the gain and it makes a different in calculation.

 

[rfry]

Can some one help me or calculate a TPO, I need to know, I'm using PSI FML-4 bays, 94 meters of Andrew 7/8 foam cable ANDAVA5-50, 6 Bfeet MLR-400 Cable adapted to the transmitter BW Broadcast TX300 v3. attached a diagram with Andrew cable information.

To produce 250 watts ERP for station W222AL, what would be my TPO? some calculation please? I'll appreciate it.

Frankie

Below is a detailed estimate of the TPO needed for this system as referenced to the CP for 250W ERP per polarization, using the directional antenna parameters shown there.

Confirming the post above by frankberry, a TPO of about 137 watts is needed for those conditions.

 

[Frankie26]

Thanks rfry