I use a scope on the IF output of the receiver, if you don't have one, its easy to add. That way, you can look at your audio, and everyone else's. You also do not need a fast scope, just the IF frequency. The R390 series receivers have a very nice IF output, works when muted....
The trapezoid pattern is better, but I never actually hooked up a scope to get one. Brett N2DTS -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bob Macklin Sent: Monday, January 09, 2006 6:13 PM To: Discussion of AM Radio Subject: Re: [AMRadio] 7285Kc tomorrow/Saturday A scope that produces the trapazopid patern is better for monitoring modulation! Bob Macklin K5MYJ Seattle, Wa. ----- Original Message ----- From: "John E. Coleman (ARS WA5BXO)" <[EMAIL PROTECTED]> To: "'Discussion of AM Radio'" <amradio@mailman.qth.net> Sent: Monday, January 09, 2006 7:13 AM Subject: RE: [AMRadio] 7285Kc tomorrow/Saturday I think what Mark is saying is that it it's difficult to tell what percentage modulation you're at when the wave form is not a sine wave and is not synced and this is true. You just have to get as close as you can with out pinching the carrier (not too often anyway). An automatic gain control circuit helps a lot with this. I did with out one for years learning how to talk by watching the scope. But it is a lot nicer and more relaxed when you have one. John -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of W5OMR/Geoff Sent: Monday, January 09, 2006 5:09 AM To: Discussion of AM Radio Subject: Re: [AMRadio] 7285Kc tomorrow/Saturday Mark K3MSB wrote: >Yes. I've tried a scope now and then (I have an old 60 Mhz B&K), but >truthfully I've never been able to really see when the modulation >level is 100% or other. I know what ideal waveforms look like (with >test inputs), but I have a hard time with a typical speech waveform. > I guess if I'm really at 20% that would be fairly easy to discern. >When I used the scope before I was trying to figure out how to tell if >I was say at 70%, 80%, 90% etc, and never felt I could do it >accurately. > Read the John/Don/Bacon page about asymetrical audio. It's written well, it's illustrated well, and completely discusses high-level, plate modulated audio and how much you -really- need. "Operating your AM Rig with out an oscilloscope, is like driving your car at night without headlights." (-K4KYV/Don Chester - AM Press Exchange) --- 73 = Best Regards, -Geoff/W5OMR ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
