From: Gordon Gibby KX4Z via groups.io

Sent: Thursday, April 3, 2025 1:54 PM

To: [email protected]

Subject: Re: [BITX20] Power zero on 10m / Drive number

I don't know about Ashhar's specific circuitry, but many of these "power" measurement systems actually measure VOLTAGE and presume 50 ohms and calculate the power using Ohms Law etc.

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If your actual impedance of your load is 25 ohms (not 50) then you will actually have FAR more output power than these kinds of systems will report.?? They are only accurate into 50 ohms precisely, zero reactance.

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Again, I haven't looked at exactly how Ashhar does his system.?? You can check this by comparing YOUR output power into a 50 ohm dummy load, and then with the same settings, into your antenna.??? If there is a difference in reported power....your antenna isn't 50 ohms and the system is being "fooled."

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I hope this helps.?? Accurate power measurement is quite an effort, which is why such equipment is often so terribly expensive!? Ashhar MIGHT have actually measured current, voltage and phase and computed, but few people do this.??

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Gordon KX4Z

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