3cx10000 Ouput Test

[GnG8d]

Isn't PEP an indication of AVG PEAK power thus the need for a power source.

Peak*Wattmeter*Board

There is no "average peak", there is peak power, peak envelope power or average power, that's it.

Do this, key an unmodulated 500w signal, or anything in the middle of one of your slugs.

Using a 500w unmodulated signal, flip the PEP switch ...... nothing happens, right? It's still 500w, unless your board is out of calibration. Now a true peak signal would be 1000w as seen on an Oscope.

Under modulation the 500w pep would remain 500w, avg would drop to 150 to maybe 200 and true peak would still be at 1000w.

Your LNA board is advertised as a "peak" board, but it is actually a PEP board.

 

[GnG8d]

pep is a pointless use of measurement

I agree, so many times harmonics or reflected power is indicated as forward pep on most of these meters.

Hate the Bird, but I like it

 

[Shockwave]

There is no "average peak", there is peak power, peak envelope power or average power, that's it.

Do this, key an unmodulated 500w signal, or anything in the middle of one of your slugs.

Using a 500w unmodulated signal, flip the PEP switch ...... nothing happens, right? It's still 500w, unless your board is out of calibration. Now a true peak signal would be 1000w as seen on an Oscope.

Under modulation the 500w pep would remain 500w, avg would drop to 150 to maybe 200 and true peak would still be at 1000w.

Your LNA board is advertised as a "peak" board, but it is actually a PEP board.

The 500 watt carrier should remain at 500 watts average when properly modulated. The modulated component of the signal adds to and takes away from the RF voltage equally in standard AM. This is why when you look at the scope, the peak crest of the modulated wave will have double the RF voltage of the carrier.

Double the RF voltage into the same 50 ohm load is not double the watts. Ohms law says power is voltage times amps. When you double the voltage into the same load, amps also double. This means the peak power should be 4 times the average since the peak voltage and current are double.

Some notes on watt meters. The typical CB meter like a Dosy does a poor job at measuring both modulated average power and PEP power. They usually show more modulated average power and less PEP power then the Bird. That has to do with sales. People are happy with a meter that doesn't show downward swing. It's cheap to add a cap and to fix that but expensive to add the required active circuits to measure true PEP.

If the Bird swing backwards on average the transmitter power amp is not capable of reproducing the required 100% positive peaks for the carrier level you are running. If the PEP meter is not active, meaning the board requires a power source for more then just the meter light, it's not able to measure the full peaks.

There is NO difference between peak power and PEP. They both mean exactly the same thing. If you think not, you're probably confused with peak to peak power. This term has been used by unscrupulous audio amp manufacturers to indicate what the power would be if you measured the potential between the positive and negative peak rather then using zero as the baseline reference. Snake oil specs.

Mack also brings up an interesting point. While the term "average peak" will likely cause controversy, this is actually what is happening on any analog meter movement. Being that the meter is a mechanical device it could never respond fast enough to track at the modulated frequencies like a scope can.

The meter itself has mechanical dampening and the circuit that measures the PEP also adds electronic dampening. This tends to hold the meter in an average position that is relative to the peaks applied. It also explains why a true PEP meter holds it's reading for a brief second after power is applied. Having a good PEP meter is the next best thing to a scope to determine the correct amount of carrier to PEP modulation levels on AM.

 

[mackmobile43]

There is no "average peak", there is peak power, peak envelope power or average power, that's it.

Do this, key an unmodulated 500w signal, or anything in the middle of one of your slugs.

Using a 500w unmodulated signal, flip the PEP switch ...... nothing happens, right? It's still 500w, unless your board is out of calibration. Now a true peak signal would be 1000w as seen on an Oscope.

Under modulation the 500w pep would remain 500w, avg would drop to 150 to maybe 200 and true peak would still be at 1000w.

Your LNA board is advertised as a "peak" board, but it is actually a PEP board.

You should talk to Shockwave before trying to school me and everything you posted in the quotations is total bunk.

 

[GnG8d]

You should talk to Shockwave before trying to school me and everything you posted in the quotations is total bunk.

Maybe you should say something instead of hiding behind shockwave?

EDIT________

Did you try the test I proposed? AVG and PEP is the same unmodulated.

 

[GnG8d]

There is NO difference between peak power and PEP.

You could be right, but THIS guy is awful convincing.

 

[mackmobile43]

There is no "average peak", there is peak power, peak envelope power or average power, that's it.

Do this, key an unmodulated 500w signal, or anything in the middle of one of your slugs.

Using a 500w unmodulated signal, flip the PEP switch ...... nothing happens, right? It's still 500w, unless your board is out of calibration.

You've pointed out the obvious, of coarse it should not move if it's calibrated which mine is so what's the point of your statement? I guess you like rereading your own thoughts?

Now a true peak signal would be 1000w as seen on an Oscope.

Post a picture of your Oscope as stated to verify your claims.

Under modulation the 500w pep would remain 500w, avg would drop to 150 to maybe 200 and true peak would still be at 1000w.

OMG! If your transistor/tubes were operated at their rated output this would not be true.
Your LNA board is advertised as a "peak" board, but it is actually a PEP board.

More (CB) snake oil, that's why I bought it, what's your excuse?

 

[Shockwave]

You could be right, but THIS guy is awful convincing.

The person who wrote that article has mistakenly used the ARRL images that represent modulated RF voltages into forming his theory that this had a proportional affect on power. As I explained above this is not the case. Power changes at a rate that is twice the proportion of the voltage change. He is simply wrong about PEP and peak power having any difference and all the numbers posted there don't make a bit of sense no matter how you look at them. The internet is loaded with misinformation. In the entire article he wrote, half of one sentence was accurate. "Typical AP readings for a 100W PEP signal usually fall between 20-30 watts"

 

[GnG8d]

In the entire article he wrote, half of one sentence was accurate. "Typical AP readings for a 100W PEP signal usually fall between 20-30 watts"

And I find that to be accurate myself, the guys claiming 50% or more have bad meters. 30% is what i typically see myself.

 

[GnG8d]

More (CB) snake oil, that's why I bought it, what's your excuse?

I want to hear your excuse, quit skirting ......... your claim of PEP being supreme is far, far from accurate.

 

[GnG8d]

Mack also brings up an interesting point. While the term "average peak" will likely cause controversy, this is actually what is happening on any analog meter movement. Being that the meter is a mechanical device it could never respond fast enough to track at the modulated frequencies like a scope can.

I think you'll find that this is PEP

 

[mackmobile43]

I want to hear your excuse, quit skirting ......... your claim of PEP being supreme is far, far from accurate.

Because smarter people than you or I have stated this on many occasions here and other viable rf forums and had you been listening you would have read this and I quote Bob85 " PEP is the only true measurement of an amplitude modulated signal" read the last 3 words in that quote then reread again.

Average power really shines in FM mode.

FM conveys information over a carrier wave by varying its instantaneous frequency and should not cause a movement in an average reading meter unless the deviation is out of wack.

 

[bushwacker]

While we're talking about it, tell me all about "average peak power" ........ I'm curious.

You own a compressor, and you don't know what I mean?
Are you kidding?

Ok I'll explain it...
If you talk loudly into a mic, you will hit close to your max peak power. But throughout a conversation, you don't talk at the same volume. These volume fluctuations in human speech effect the peak power output. If you talk softly into the mic, you won't get the same peak power output as you would if you yelled into the mic.

During a conversation, the modulation ( through the whole conversation) will bounce between 60% and 100% ( for example). This means your average modulation through a conversation is around 80%.
If your looking at a peak meter...and your max output is 100 watts fully modulated ( for example)...you would have low peaks at 60 watts and highs at 100 watts.
What the compressor does is increase your average modulation...it brings up the modulation lows that were at 60% up to 80% (for example)....so now when you talk softly, insted of hitting 60%...your now up to 80%. This means your lowest peak power has also increased.

Though a conversation, your now bouncing between 80% and 100% modulation. This means your peak power is now bouncing between 80 watts and 100 watts( using the above example) and sounds louder.
Though the conversation you have increased your "average peak power".
This is why your signal sounds louder with a compressor. Insted of your peak power bouncing between 60 watts and 100watts through a conversation.....its now putting out between 80 watts and 100 watts peak with the compressor.

You have increased your average peak power....you were averaging between 60 watts(60%) and 100 watts (100%).....now your averaging between 80 watts and 100watts through a conversation.

If you wanted to you could compress down the peaks to 90% and bring up the lows to 85% modulation...this means even if you talk softly into the mic you will always hit 85% modulation and never go over 90%. If we use the same example as above and convert this to watts on a peak meter...your average peak power through a conversation will always be around 87 watts no matter how soft you talk.

There is a relationship between peak power and modulation....increasing your average modulation through a conversation will also increase your "average peak power".

This is why your not seeing any difference on an RMS meter with your compressor on (assuming your running 100%modulated). You can't see your modulation lows or lows in pep power.
Its not about an "average reading" on a meter.....its about the average peak power your putting out through a conversation.

Once you learn how a compressor increases your average modulation, then you can go on to see how it will effect your peak power
If you increase your average modulation through a conversation, you will also increase you average peak power through a conversation..

Just like there is an average modulation through a conversation....so is there an average peak power through a conversation.

 

[bushwacker]

I have to agree with some of what is said.

A peak meter reading is only a vaugue indication of modulation....not power.
Technically, the power is in the carrier.

 

[Shockwave]

I think you'll find that this is PEP

To measure true modulation peaks at any given time requires a scope. The point here is the meter and your eye are not fast enough to track the real variations in modulated peak power. This forces the meter to take an average of the peaks applied over the period of time it takes to charge a capacitor. You are right in saying this is PEP power shown on the Bird 43P. However, Mack is also right in suggesting the method the meter arrives at this PEP value is averaged over the time it takes to charge the capacitor in the PEP circuit.

Since PEP power is always fluctuating with modulation, the meter is rarely correct at any given time. The capacitor does charge to the peak of the applied RF voltage with the help of the active circuit in the meter. The average point becomes relative when you consider time as a variable over the course of normal modulation. One good example is on SSB between words when the PEP power should be zero. Yet the PEP meter will still continue to display the last peak applied until the cap discharges. I think this is Mack's point.