Author |
Message |
Bob_p
Intermediate Member Username: Bob_p
Post Number: 203 Registered: 7-2004
| Posted on Wednesday, August 18, 2004 - 10:14 pm: |
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I was just wondering if someone could explain db gain in very simple terms. |
Bruce
Senior Member Username: Bruce
Post Number: 1486 Registered: 9-2003
| Posted on Wednesday, August 18, 2004 - 11:28 pm: |
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YEP 3db= 2x power 6db= 4x power 9db= 8x power 10 = 10x power 13 = 20x power 16 = 40x power 19 = 80x power 20 =100x power Now to get gain you have to compress the pattern a good example is if you want 9 db gain omidirectonal with a vertical you must compress the vertical lobe to about 10 deg to do this takes 8 1/2 wave antennas phased above each other LOOK AT A GOOD UHF BASE ANTENNA WITH 9DB GAIN it will have 8 PHASED ANTENNAS one on top of the other. A 2 bay one 3db gain
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Bc910
Junior Member Username: Bc910
Post Number: 45 Registered: 7-2004
| Posted on Wednesday, August 18, 2004 - 11:52 pm: |
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DB gain is what happens when you eat too many doughnuts, FYI The term DB stands for "Dough Boy" so when someone is talking about DB gain they are realy talking about a weight problem. Oh no wait, thats right, I have no idea, what was I thinking? .......... Sorry, I don't know, but good question, I wanna know too! BC |
Bob_p
Intermediate Member Username: Bob_p
Post Number: 206 Registered: 7-2004
| Posted on Thursday, August 19, 2004 - 1:21 am: |
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Thanks Bruce I knew it was a multiplication of the radios power but did not know what that was. I actually thought 3db gain was three times the radios power. So I guess on an I-Max 2000 with 3db gain would double the power of the radio it’s self. Thanks for guideline it really helps |
Bob_p
Intermediate Member Username: Bob_p
Post Number: 208 Registered: 7-2004
| Posted on Thursday, August 19, 2004 - 1:14 pm: |
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I have another questioin as a follow up. Does that mean that a 1/2 wave like the A-99 at about 2db would have 1.334X power then? |
Bruce
Senior Member Username: Bruce
Post Number: 1488 Registered: 9-2003
| Posted on Thursday, August 19, 2004 - 2:27 pm: |
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YEP Over a isotropic antenna. REMEMBER unless the gain SAYS DBD its DBI. A ISOTROPIC antenna is one that radiates equaly well in every direction. |
Bob_p
Intermediate Member Username: Bob_p
Post Number: 210 Registered: 7-2004
| Posted on Thursday, August 19, 2004 - 3:38 pm: |
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Bruce. Thanks alot. I really appreicate your willingness to share knowledge. |
Bruce
Senior Member Username: Bruce
Post Number: 1489 Registered: 9-2003
| Posted on Thursday, August 19, 2004 - 6:30 pm: |
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BOB thats what this forum is all about......
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