| Author |
Message |
    
Jerry Bryant
| | Posted on Thursday, May 31, 2001 - 9:45 am: | 
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What are peoples opinions based on experience with different radios audio quality,whether "clipping" yields better audio or just adjusting the variable resistor wide open? |
307 (307)
| | Posted on Thursday, May 31, 2001 - 10:23 am: |
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Jerry , I would like to answer that. "Clipping" the audio limiter is a fast way to show an owner that his/her radio is putting out more power than it is really capable of. When you "Clip"(Flat-top) a sinusoidal waveform , it tends to create more harmonics that ride on top of the flat area. These are called "Nodels". When you present this to a meter , it sure looks good! The problem is so many people buy into this that it is a loosing battle telling people the REAL way is to leave the limiter in place and crank up the pot. The "Clipping" actually lets the radio over modulate through the pass band filter and will splatter as well. You can NOT tell the difference in Audio , Those who tell you that you can are wrong , If you look on an Audio Analyzer (HP) you will see the SAME results. One sounds good with NO splatter , the other sounds good with massive splatter. |
Jerry Bryant
| | Posted on Friday, June 01, 2001 - 12:52 pm: |
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Mr.307 sir,thank-you for clearing up this issue on clipping radios,and the negatives involved.I've heard countless radios on channel 6 "the Superbowl" and even skip stations on the west coast will have splatter of about 4 channels away here in Oakland Park,FL. For now on I'm going to leave the limiters in place in future rigs.73's and thanks again. J.C.B. |
975
| | Posted on Sunday, March 10, 2002 - 3:32 am: |
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Couldn't agree more with 307 on this one... all you are seeing is "splatter" on the meter... let me ask my fellow radio operators this: Can your watt meter tell the difference between frequencies? Probably not....
THEREFORE: Your wattmeter is reading your actual output along with anything else (within the spectrum) comming down the line.
Thus: Man my radio really swings!! I get 150% modulation!! Umm no you don't.... can you fill two classes of water into one? NO! And can two sidebands ride on pratically no carrier? NO!! You'll start operating in double sideband mode, which isn't good either, because most amplification circuits in the output of the radio are in class-C mode when the radio is operating AM, therefore, you have clipped over-modulated AM/double sideband, (somewhere in between)amplified in class C mode (can we say splatter, spurious emmissions?) |
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