| Author |
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Jose22
| | Posted on Sunday, May 05, 2002 - 10:27 am: | 
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I have been reading this forum for a while. I am still a little confused. What is the the best way to get "Swing". I have read cut this or turn that and then read dont cut. To make the radio Loud do you need swing or Dead key watts. If you go by alignment sheet for say Cobra 29 , you tune the vco/pll, receiver and peak out dead key watts, then tune L11 or l14 back to legal 4 watts. If you cut something it makes the meter look good but are you really getting the best clean swing? Should I be peaking out wattage using modulation or dead key? How do you measure clean output, and not splatter? Is there really a answer? Is there a book or video available? What I am really after is LOUD , CLEAN, and able to drive amp sometimes but not allways. If I adjust Modulation with scope what input should I use. 1k tone at 3mv direct input or tone at normal room level? Soooo.... many questions, so few really truths. HELP Please.
Jose22 |
Galileo
| | Posted on Sunday, May 05, 2002 - 3:23 pm: |
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Really good questions.....I look foward to seeing the answers myself... |
Taz
| | Posted on Sunday, May 05, 2002 - 6:21 pm: |
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Loud is by opinion. Somone might say its loud then somone else might say its over modulated. To be loud you need to acheive 100% modulation. You can go over but then it starts to sound bad. When you peak and tune a radio you want to get the most swing you can get out of it not deadkey. Dont cut the limiter, thats for ch.6 people who want to be overmodulated. As for your splatter questions somone who has experience with scopes could better explain it like 307,181,bruce, bullet. |
Warlock
| | Posted on Sunday, May 05, 2002 - 9:15 pm: |
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There is a method to achieve the "swing" or low carrier with near full modulated power without changing transistrs, jumping voltage, or removing limiters.
The loudness is generally increased as the carrier decreases, as long as the modulated power does not fall equally as the carrier. Typically if you have a 4:1 peak to carrier ratio you will be near 100% modulated carrier. If you are using an amp that requires a lower carrier, it must be supressed so as to achieve the same 4:1 ratio from the amp. This leaves (many times) the radio with as much as 20:1 ratio. When operating the radio alone you can bring the audio wave form back in line by simply reducing the mike gain.
If you need further help you can email me. |
Jose22
| | Posted on Monday, May 06, 2002 - 10:16 pm: |
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Warlock, thanks for the info. 4 to 1 is easy enough. What about getting 100% Modulation. I can adjust using 1K tone with mike close to speaker or place a 1K tone directly into radio. The tone into mike can yeild different results depending on how close the mike is to output, or how loud speaker is. Can adjust using soft tone to 100% on scope, and then when tone is louder or mike closer it will show over. What is the best rule to go by? Also is there any way to tell if you wattmeter is measuring true & clean output or splatter?
Thanks Again
Jose22 |
Warlock
| | Posted on Tuesday, May 07, 2002 - 11:04 pm: |
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I'd adjust it with your voice in a peak sound such as "heeeello" or "auuuudio". This is what environment the radio will be used, your voice.
The only way to tell if you are producing IMD or TVI is with a spectrum analyzer and oscilliscope. Typically if you do not change biasing, overvolt, or rearrange tuning COILS, you will not need to worry with "splatter" as long as you are at or below 100% modulation and/or 4:1 peak to carrier. |
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