Amplitude modulation and needle power meter reading

[neazoi]

I set the old Yaesu FT-101E for AM transmission as described in the manual and I get 20-25W carrier (ok) and when I speak to the mike, I only see the external wattmeter needle I have, move just a little.

Shouldn't I see a big movement in the meter upwards?

Also, A yaesu FT-301 does the same thing. In comparison a kenwood ts-480 outputs a 40W carrier which goes to 80W when I speak loudly. But it may be over modulation, I do not know, cause there is an ALC modification inside.

What is the case with AM, should I see the wattmeter needle move much, above the carrier, like in SSB or not?

The way I am thinking it is like SSB. But instead of zero output, I should see the idle carrier. Then, like SSB, when I speak to the microphone, I should see the power meter going up, peaking towards the full output power capability of the transmitter.

I assume an upwards AM modulation in my post.

--- Updated Jun 9, 2021 ---

I read this article https://ham.stackexchange.com/quest...m-transmitters-increase-when-modulated-and-of and now I am more confused.
Clearly in an upwards AM, the carrier should be set to 25W and one should expect 100W PEP.

He says "The carrier average power will be 2/3 of the 100% of the modulated average power.
Does it mean that the carrier level also goes up and down with the modulation?
I thought that the carrier would stay at the same level when modulation applied and only the sidebands go up and down!

Shouldn't I see a significant movement of the needle of the average power level during AM modulation?

 

[G4BCH]

What the power meter reads will depend on what the power meter is designed to read, if irs peak power then it will increase as you modulate the carrier; the peak power is higher. If is reads average power, more common for power meters, then the readin should hardly change, the average power remains constant when modulation is applied.
Think about the carrier being modulated by a sine wave, over one cycle the time that is spent above the average power is equal to the time that is spent below the average power; i.e the power remains at the average.

 

[neazoi]

What the power meter reads will depend on what the power meter is designed to read, if irs peak power then it will increase as you modulate the carrier; the peak power is higher. If is reads average power, more common for power meters, then the readin should hardly change, the average power remains constant when modulation is applied.
Think about the carrier being modulated by a sine wave, over one cycle the time that is spent above the average power is equal to the time that is spent below the average power; i.e the power remains at the average.

I think that explains everything

This raises more questions of wheather the cross-needle power SWR meter I am using has a peak detector or not (It is a passive meter no DC is required for it's operation). With that meter, I see 100W, when I whistle on the microphone on SSB mode. This equals the single tone measurement on SSB in the video, which gives a constant amplitude of 100W, hence the meter needle shows 100W.
But when whistling on AM, the needle of the meter does nothing (barely moving from it's 25W position). This is like the single tone AM measurement in his video. The AVERAGE power is equal to that of the idle carrier power (25W) because the carrier is half of the time double in power (50W) and half of the time half the power (12.5w), which equals to an average power of 25W, just like a plain unmodulated carrier.
So I believe this is the reason why on AM the needle of my meter does not move, because the meter is an average power one.
I think I get this right now, please let me know if not.

This raises another question. Why on the TS-480HX (200W SSB) I see an unmodulated carrier of 40W and a modulated carrier (whistle on mike) of about 80W on that same power meter? Does the ALC have anything to do with it?