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Re: Measuring the output power

 

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To the original poster (on3plz ?):

I've been following this thread, and maybe I've missed something, but I have a question that I don't see any answers to-? particularly since this is a ft817 group- why do you feel a need to measure power?? I presume it's a measurement at maximum level of 5 watts, or perhaps a bit more- but knowing why you desire to make measurement(s) helps with answering the question:

(a) if you're looking to make some adjustments to "peak" a power output adjustment, it's probably not necessary to accurately measure the actual power level- a simple analog meter (VTVM, or VOM) connected to a signal (or germanium) diode detector that's measuring the voltage across a 47, 50, or 51 ohm non-inductive resistor might be sufficient as it provides a relative measurement, where small changes can be easily observed

but

(b) if you're looking to increase the ft817 power output above 5 watts- I've been told that it can be done- but I suspect that you will be stressing the radio

and

(c) if you're looking to get accurate measurements of power output (to several decimal places) keep in mind that such accuracy is difficult to provide without calibrated instruments and reference elements (for example- dummy load characteristics).

Mike N4MWP

On 6/25/24 16:31, Ham Radio wrote:

[Edited Message Follows]

You can build a simple RF probe but you need to calibrate it. ?A simple SWR meter does not measure power over a wide range of frequencies. ?If possible, borrow a Bird 43 wattmeter from a local ham.

You can use that device to calibrate the power of your measurement equipment.

Check out kc9om.com. ?He sells some great kits and gives excellent service.

You can also build own watt meter using a Arduino UNO, a power tap and dummy load

See my rather crude video that I produced 4 years ago to see a demo of a talking watt meter.
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