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How to calculate the TPO

Frankie26

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
 

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  • TPO.pdf
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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?
 
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.
 
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.
 
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.
 
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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.
 
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.
 

Attachments

  • GAIN INPUT db.png
    GAIN INPUT db.png
    243.6 KB · Views: 5
Frankie26 said:
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
Click to expand...

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.
W222AL TPO Calculation.jpg
 
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