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See

?

for the full treatise.

73,

Kim N5OP

I agree with the later part of your response, but you sort of contradicted yourself with

""Peak" on a watt meter is the peak power, which is always part of a a running-RMS (like a running mean but RMS instead) power. "

but then you said ;

"There is no such thing as "RMS power"

I guess my point is getting back to basic AC, is looking over a 360 degree cycle? with peak, valley and then a rms value to equate it to a DC constant.

I agree that power that varies over time can have max and minimum value for the time mapped.

Do you agree with Kims comment re "There’s no such thing as “RMS power”; peak power come from peak RMS values."

In the audio world ;

Root mean square or simply RMS watts refers to?continuous power handling of a speaker or a subwoofer or how much continuous power an amplifier can output. RMS values are usually lower than peak watts ratings, but they represent what a unit is truly capable of handling.

73

vk4tux

peak power come from peak RMS values

On 18/4/25 09:32, Kim Elmore via groups.io wrote:

That's simply incorrect. Our voice "peaks" are very long, compared to the RF frequency, they they have do indeed have a running RMS value. "Peak" on a watt meter is the peak power, which is always part of a a running-RMS (like a running mean but RMS instead) power.?

Your house current id 60 Hz and has a peak voltage of about 169 V. Is your light blulb or power input to you amp rated based on 120 VAC or 169 V peak AC? Yes, wire insulation must be rated for the peak voltage it is to with stand, but it's current carrying capacity is rated in the RMS current. There is no such thing as "RMS power": it's simply power, computed based on the RMS voltage, current, or the RMS voltage squared over the impedance, or the RMS current squared milipaited by the impedance.

73,

Kim N5OP

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Power is RMS. Power can vary, but it's always RMS. The idea is that for sine wave AC, RMS voltage and current will dissipate the same power as the DC values for both. My digital vector RF watt meter does not magically switch to computing power from the peak RF voltage when I switch it to peak. To do would be nonsensical.When I select "average" it yields the average over some integration period; it doesn't switch to RMS.?

73,

Kim N5OP

I agree with the later part of your response, but you sort of contradicted yourself with

""Peak" on a watt meter is the peak power, which is always part of a a running-RMS (like a running mean but RMS instead) power. "

but then you said ;

"There is no such thing as "RMS power"

I guess my point is getting back to basic AC, is looking over a 360 degree cycle? with peak, valley and then a rms value to equate it to a DC constant.

I agree that power that varies over time can have max and minimum value for the time mapped.

Do you agree with Kims comment re "There’s no such thing as “RMS power”; peak power come from peak RMS values."

In the audio world ;

Root mean square or simply RMS watts refers to?continuous power handling of a speaker or a subwoofer or how much continuous power an amplifier can output. RMS values are usually lower than peak watts ratings, but they represent what a unit is truly capable of handling.

73

vk4tux

peak power come from peak RMS values

On 18/4/25 09:32, Kim Elmore via groups.io wrote:

That's simply incorrect. Our voice "peaks" are very long, compared to the RF frequency, they they have do indeed have a running RMS value. "Peak" on a watt meter is the peak power, which is always part of a a running-RMS (like a running mean but RMS instead) power.?

Your house current id 60 Hz and has a peak voltage of about 169 V. Is your light blulb or power input to you amp rated based on 120 VAC or 169 V peak AC? Yes, wire insulation must be rated for the peak voltage it is to with stand, but it's current carrying capacity is rated in the RMS current. There is no such thing as "RMS power": it's simply power, computed based on the RMS voltage, current, or the RMS voltage squared over the impedance, or the RMS current squared milipaited by the impedance.

73,

Kim N5OP

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Keep in mind that a single sine wave cycle has an RMS value that is peak/1.414.

73,

Kim Elmore

That's simply incorrect. Our voice "peaks" are very long, compared to the RF frequency, they they have do indeed have a running RMS value. "Peak" on a watt meter is the peak power, which is always part of a a running-RMS (like a running mean but RMS instead) power.?

Your house current id 60 Hz and has a peak voltage of about 169 V. Is your light blulb or power input to you amp rated based on 120 VAC or 169 V peak AC? Yes, wire insulation must be rated for the peak voltage it is to with stand, but it's current carrying capacity is rated in the RMS current. There is no such thing as "RMS power": it's simply power, computed based on the RMS voltage, current, or the RMS voltage squared over the impedance, or the RMS current squared milipaited by the impedance.

73,

Kim N5OP

On 4/17/2025 6:04 PM, Adrian Fewster via groups.io wrote:

Well our RF wattmeter usually has peak and avg selections ?? RMS is converting the AC to a DC value that is constant to

determine the constant heat W emitted. At a peak time snapshot , peak power and peak voltage are true for that moment.

Think of it like shoveling coal into a boiler. The heat produced is determined by the average coal added? time rather than peak

coal added in a moment.

So 'peak RMS values ' does not make sense, as once converted to rms there are no peaks nor valleys for the math purpose.

73

vk4tux

On 18/4/25 05:33, Kim Elmore via groups.io wrote:

I can’t help but chime in: RMS is the only value that makes sense. Outlet voltage in your house is 120 V RMS. There’s no such thing as “RMS power”; peak power come from peak RMS values.?

Kim

N5OP

"People that make music together cannot be enemies, at least as long as the music lasts."?-- Paul Hindemith

On Apr 17, 2025, at 11:55, KG2RG via groups.io <justinandyazny@...> wrote:

?

Duty cycle is considered. These are peak voltage obtained by 100% duty cycle continues wave.

?

the Eimac formula for calculating grid dissipation is based on peak.?
Pg = vga X Ig

?

anyway, anything I state is like I said, this is what I know, how I calculate it. I’m not an engineer, just an amateur. There are plenty of engineers floating around here and if I’m incorrect, I would love to be corrected as that would benefit myself and I’m always open to learning more. Any day I can learn is a day of victory.

?

PS, this stuff is the fun part of the hobby!?

?

73!!

--

Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP SEL/MEL/Glider, UAS, N5OP, 2nd Class Radiotelegraph, GROL)

“Listen, it's too big a world to be in competition with everybody else. The only guy I have to get better than is who I am right now.” – Col. Sherman T. Potter, 4077 M.A.S.H.

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I believe those were peak *input* power levels. This is what upset AM fans so much when it was changed to 1500 W peak output, because they could get more than 1500 W peak? power with 2000 W peak input running Class C plate modulation.

73,

Kim N5OP

Grids don’t have enough thermal mass for protection like a plate has.? Exceeding peak values are enough to blow out a grid.

?

Many moons ago, I had a Henry 3-KA it had a pair of Eimac 3-500Zs had sheet metal plates and ~ 3500 Volts on the plates.? It was a beast.? It was a mess when I bought it.? I had to rebuilt the plate circuit wiring and replace the noisy plate circuit fan.? I replaced the fan with a more powerful Dayton squirrel cage blower.

This was in the days when the US FCC power limits were 2K peak output.? The FCC intended that 2K peak to be for SSB. ?But the rule was written 2KW peak.? 2KW peak for SSB is also 2 KW peak for CW. ?At that power level the plates were a nice dull red—just like the spec sheets says.? And a Bird Wattmeter indicated 2 KW output—probably exceeded the 500 Watt per tube dissipation but the greater air volume helped mitigate that some.? Worked out well for a bunch of CQ World-Wide Contests.

?

73,

Dave, w6de

?

From: [email protected] <[email protected]> On Behalf Of Kim Elmore via groups.io
Sent: 17 April, 2025 19:33
To: [email protected]
Subject: Re: [ham-amplifiers] SB-1000

?

I can’t help but chime in: RMS is the only value that makes sense. Outlet voltage in your house is 120 V RMS. There’s no such thing as “RMS power”; peak power come from peak RMS values.?

?

Kim

N5OP

?

?

"People that make music together cannot be enemies, at least as long as the music lasts."?-- Paul Hindemith

On Apr 17, 2025, at 11:55, KG2RG via groups.io <justinandyazny@...> wrote:

?

Duty cycle is considered. These are peak voltage obtained by 100% duty cycle continues wave.

?

the Eimac formula for calculating grid dissipation is based on peak.?
Pg = vga X Ig

?

anyway, anything I state is like I said, this is what I know, how I calculate it. I’m not an engineer, just an amateur. There are plenty of engineers floating around here and if I’m incorrect, I would love to be corrected as that would benefit myself and I’m always open to learning more. Any day I can learn is a day of victory.

?

PS, this stuff is the fun part of the hobby!?

?

73!!

?

开云体育

That's simply incorrect. Our voice "peaks" are very long, compared to the RF frequency, they they have do indeed have a running RMS value. "Peak" on a watt meter is the peak power, which is always part of a a running-RMS (like a running mean but RMS instead) power.?

Your house current id 60 Hz and has a peak voltage of about 169 V. Is your light blulb or power input to you amp rated based on 120 VAC or 169 V peak AC? Yes, wire insulation must be rated for the peak voltage it is to with stand, but it's current carrying capacity is rated in the RMS current. There is no such thing as "RMS power": it's simply power, computed based on the RMS voltage, current, or the RMS voltage squared over the impedance, or the RMS current squared milipaited by the impedance.

73,

Kim N5OP

Well our RF wattmeter usually has peak and avg selections ?? RMS is converting the AC to a DC value that is constant to

determine the constant heat W emitted. At a peak time snapshot , peak power and peak voltage are true for that moment.

Think of it like shoveling coal into a boiler. The heat produced is determined by the average coal added? time rather than peak

coal added in a moment.

So 'peak RMS values ' does not make sense, as once converted to rms there are no peaks nor valleys for the math purpose.

73

vk4tux

On 18/4/25 05:33, Kim Elmore via groups.io wrote:

I can’t help but chime in: RMS is the only value that makes sense. Outlet voltage in your house is 120 V RMS. There’s no such thing as “RMS power”; peak power come from peak RMS values.?

Kim

N5OP

"People that make music together cannot be enemies, at least as long as the music lasts."?-- Paul Hindemith

On Apr 17, 2025, at 11:55, KG2RG via groups.io <justinandyazny@...> wrote:

?

Duty cycle is considered. These are peak voltage obtained by 100% duty cycle continues wave.

?

the Eimac formula for calculating grid dissipation is based on peak.?
Pg = vga X Ig

?

anyway, anything I state is like I said, this is what I know, how I calculate it. I’m not an engineer, just an amateur. There are plenty of engineers floating around here and if I’m incorrect, I would love to be corrected as that would benefit myself and I’m always open to learning more. Any day I can learn is a day of victory.

?

PS, this stuff is the fun part of the hobby!?

?

73!!

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Sorry, Eimac said different in "care and feeding of power grid tubes".

Ahhha... in that example, Eimac is calling the SWING of plate or grid voltage "peak".

*I've* always considered the "peak plate voltage" to be the most positive voltage that the plate can attain (and the corollary is the "negative peak plate voltage" would be the most negative plate voltage), and I think the rest of us have done so, too. But in that example, that writer is NOT using that same "definition" and in fact, at the end of that first paragraph, he seems to mix (or at least combine) terms when he says "This is a peak swing of 220 volts, and the peak r-f grid voltage is 220 volts.".?

And just prior to that, he writes "... the greatest each value swings away from the d-c value. This is known as the peak value of the r-f voltage."

Looks like a matter of semantics? 8-)

Steve, K0XP

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Sorry, Eimac said different in "care and feeding of power grid tubes".

Your formula is for driving power.

?

73

Peter

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-----Original-Nachricht-----

Betreff: Re: [ham-amplifiers] SB-1000

Datum: 2025-04-16T03:03:50+0200

Von: "KG2RG via groups.io" <justinandyazny@...>

?

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###? ?On the SB-1000,? AL-80B, they rate it at 1000w? pep out on SSB? (550 ma).....and? only 850 watts out on CW (450 ma).

(A) 70.7 vrms x .3 =? 21.21 watts? ?grid diss
(B) 100 V peak? x .3? =? 30 watts grid diss.

Perhaps Reid Brandon? will chime in.? ?Right now, I can't fathom why Eimac would use peak cathode RF voltage? instead of RMD cathode voltage.