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Cmenchion
New member
Username: Cmenchion
Post Number: 3
Registered: 4-2011
| | Posted on Wednesday, April 27, 2011 - 4:03 pm: | 
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Hi again, I have a Dosy 4001. Testing a TR-696-FD1. 1.5w dk and peak 13w. I try to check my modulation but I cannot get the meter to swing to the set position. Only half way up the meter.
My question is:
Is this because my modulation is too low? And if I turn the modulation pot up and recheck I will be able to set my radio to 100% Mod give or take?
Thanks again  |
Tech833
Moderator
Username: Tech833
Post Number: 1964
Registered: 8-2002
| | Posted on Thursday, April 28, 2011 - 1:10 am: |
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If your carrier power is 1.5 watts and your peak power is 13 watts, it certainly is not because your modulation is too low. If anything, it is way too high. You are likely pinching the carrier, so on negative peaks, the radio is putting out zero watts. That will make calibrating a meter an exercise in futility.
Your radio 'Mythbuster' since 1998
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Cmenchion
New member
Username: Cmenchion
Post Number: 4
Registered: 4-2011
| | Posted on Thursday, April 28, 2011 - 12:00 pm: |
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It was also suggested to me that having the radio DK at 1.5w is not enough power for the meter to read. I may try to turn the DK back to 4w and try again.
Thanks |
Sitm
Intermediate Member
Username: Sitm
Post Number: 428
Registered: 1-2004
| | Posted on Thursday, April 28, 2011 - 12:17 pm: |
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Throughout the history of CB operators have been striving to achieve LOUD MODULATION. At times it seems that the louder, the better, regardless of the amount of distortion, spurious emissions and distortion (aka bleed over) that occurs. In fact I have personally heard cb operators gauge the ability of their radio by how many channels they are “bleeding”. Only in the 11 meter band is this measure of success considered a “good thing” as when you move into the ham bands spurious emissions (bleed over) is considered the mark of a novice operator.
Most Citizen Band radios are producing between 50% to 80% modulation from the factory. If set properly with a constant tone at 100% rarely with normal speech will a radio reach 100% modulation during a conversation. Where many errors occur is when a operator turns their modulation pot to 100%, has a “swing kit” installed and then purchases a modulation microphone which causes the emission of the radio to easily exceed 100% modulation, or “AM I LOUD” modulation. In truth your radio is producing spurious emissions, harmonics and distortion of what was once a clean emission signal.
In truth a properly tuned radio with a properly adjusted amplifier (1 x 4 scale) will achieve the same distance of communication and most often further. Of course you will have to sacrifice transmitting your signal on seven frequencies to each side of your intended broadcast channel. Achieving 100% modulation on your radio means that you have reached the maximum affective level at which your radio will broadcast “effectively”. Of course this term is relative to the level of experience the radio operator has and level of understanding of theory understood.
Let me use a garden hose as a metaphor in this explanation. Everyone has used a garden hose. On the setting that allows no restrictions on the flow most certainly entire flow of the hose is expelled. It will cause the immediate area and to a certain distance out to be wet. But put the hose on a stream setting and it causes the water to be pushed to its furthest distance out causing the area that is intended to be watered only. Or put it on the setting where it comes out somewhat like a shower. Only the immediate area gets wet………..but boy are you LOUD.
Setting your radio with proper modulation is like setting a garden hose to stream. Your radio is broadcasting only on the intended frequency achieving the maximum distance your broadcast is capable of. Over modulation is like setting a garden hose to that the maximum wattage and modulation is being broadcast. Generally this is causing harmonics and spurious emissions on several channels to each side of your intended frequency to be affected unintentionally.
There is a point at which you have to decide what type of an operator you want to be. If you have a radio that is over modulated and distorted you will always be able to find people that will tell you that you sound fantastic. Like if you are a drunken idiot you will always be able to go to the bar and people will tell you that you don’t drink too much. Start reading some technical information on radio broadcast and you will see that some of the myth and folklore that is still being repeated to this day is nothing but miss information that will never help you achieve the most from your radio equipment.
When you purchase a radio from Copper Electronics and request the tune and align, most often your radio is achieving near 100 persent modulation. But lets face it we operators for the most part are men. When we are young, we want our cars and women louder and faster. Eventually when we grow up we are ok going the speed limit and a not so loud fast woman.
Learn how your radio will achieve 100% from education in the radio field and I assure you you will not be so impressed by "am I loud" and more impressed by hearing "wow you are crystal clear". |
Cmenchion
New member
Username: Cmenchion
Post Number: 6
Registered: 4-2011
| | Posted on Friday, April 29, 2011 - 7:09 am: |
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Hey stim. You hit the nail on the head man. Like everyone wants to be loud and clear at the same time. I know everyone tells me they can't get over the audio of my radio. I don't want to ruin that at all. But I do what my radio to work at the best it can whether that be like you said 80% mod or 100% or 60%. What works the best is what I am striving for.
The radio has never been touched my anyone but me, All I have done with it is set the DK and where the darn radio drifts a lot. I have to set my radio for winter and summer. As it gets warmer out it'll drift more on to freq so I have to adjust the LSB (where i do all my talking) pot to bring the freq down to where it will drift to xx.xx50 on tx/rx.
I understand 100% what your saying, I want to me heard don't get me wrong but I want to keep my good audio. I use a stock mic etc, So for me adusting the mod to 100% may help or may make it a little worse. I have to set it first to see.
Copper did not have these radio's when I went to buy them, they were already discontinued and only a few places had stock left. I am glad I bought the radio, I've never had so many compliments on it.
Thanks again for the info, greatly appreciated.
cmenchion |
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