I think that was my point. An instrument could be made to capture any peak that went over the limit. It only takes one. But if you have one you probably have more.
In my opinion the thing for the average ham to do is set their monitor to display the maximum the want to transmit on their monitor. If they see the trapezoid flashing over that point they will know they have a problem. But they will never see a single cycle. The thing to do is not worry about it until you get a notice. Just don't push your modulation to the legal limit! Bob Macklin K5MYJ Seattle, Wa, "Real Radios Glow in the Dark" ----- Original Message ----- From: "John Coleman" <[EMAIL PROTECTED]> To: "'Discussion of AM Radio in the Amateur Service'" <[email protected]> Sent: Thursday, February 14, 2008 4:32 PM Subject: RE: [AMRadio] Modulation power required Bob: As you pointed out earlier it is nearly impossible to measure a single cycle. It is just a definition. When looking at the trap pattern or an envelope pattern one can get a pretty fair measurement of the peak voltage of the envelope. There is even meters that will give you the peak RF of an envelope or just the peak RF of the carrier. Then you can make the assumption that the single RF cycle which exits at that most extreme point of the envelope has the peak voltage of the envelope. Calculate the RMS value of that carrier voltage before putting the value in the power formula. Power can only be calculated from RMS values of RF voltage or current. (.707 Ep = Erms) Ep is the peak RF voltage at the extremes of the RF sine wave with respect to 0V center line. Erms squared / 50 ohms of the dummy load = PEP for that envelope With out modulation the carrier power is calculated the same way. Measure the peak voltage of the RF Multiply by .707 Square the product Divide by 50 BTW if your using a scope to measure the RF voltage the peak will be 1/2 the peak to peak of the RF on the scope. Also I have a circuit using a 6AL5 which can be mounted in a small chassis and affixed to the top of a Can-tenna which will allow measurement of the peak RF voltage with very good accuracy. If you interested. John, WA5BXO -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bob Macklin Sent: Thursday, February 14, 2008 5:33 PM To: [EMAIL PROTECTED]; Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Modulation power required "E squared / R will give average power." So how do you do that on a single cycle? Bob Macklin K5MYJ Seattle, Wa, "Real Radios Glow in the Dark" ----- Original Message ----- From: "Gary Schafer" <[EMAIL PROTECTED]> To: "'Discussion of AM Radio in the Amateur Service'" <[email protected]> Sent: Thursday, February 14, 2008 3:13 PM Subject: RE: [AMRadio] Modulation power required > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:amradio- > > [EMAIL PROTECTED] On Behalf Of Bob Macklin > > Sent: Thursday, February 14, 2008 5:19 PM > > To: Discussion of AM Radio in the Amateur Service > > Subject: Re: [AMRadio] Modulation power required > > > > Why not just calibrate a Trapezoid display for MAXIMUM PEP? The just watch > > the trapezoid display? > > > > Watching a single cycle on a scope is a difficult thing to do. > > > > HOW DO YOU AVERAGE PEP ON A SINGLE CYCLE? > > E squared / R will give average power. > > 73 > Gary K4FMX > > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Searchable Archives: http://www.mail-archive.com/[email protected]/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected] > To unsubscribe, send an email to [EMAIL PROTECTED] with > the word unsubscribe in the message body. > ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
