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How to measure TX's power output ?

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As a very rough guide measure the power going in and think maybe half is going to be your output power. There are lots of ways to measure RF, if you google it will give you many options. Why do you need to know?


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If you want a real measurement that is worth something (i.e. gives you info both about power and frequency accuracy), you'll have to find someone with access to a spectrum analyzer (which is a very expensive piece of equipment).

The output power vs input power doesn't say anything, from my experience output power can be anywhere between 1/2 to 1/5 of input power depending on design, and especially a TX that is defective or sends spurious everywhere (=bad quality) will still use the same input power.

Edited by Kilrah

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I bought video tx (1.3ghz) 800mw and another one 1500mw.

Is there any way to measure poweroutput is real ?

The cheapest most accurate way would be to find a 'ham' in your area with a bird or coaxial dynamics wattmeter and offer to buy him a 'slug' for the frequency and power you are using. Give him the slug for payment for borrowing his meter. If you are more diy you can rectify the rf feed into a 50 ohm dummy load and measure the voltage to calculate watts.


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I have a bird wattmeter which I use to test transmitters output. Unfortunately I only use the 900 Mhz

band and have no slug for 1.3. As the previous poster said if you would be willing to buy the slug I

could test all your units.

Yet a spectrum analyzer would be better as it would tell you RF energy radiated at your specific wanted

frequency versus a summation of all power out. My cheap USB spectrum analyzer only works in the 900 Mhz

band but has taught me volumes about transmitters I have purchased.

The bird wattmeter lets me match antennas to transmitters and see how transmitters are performing.


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