| Author |
Message |
    
Outkast
Junior Member
Username: Outkast
Post Number: 16
Registered: 9-2005
| | Posted on Monday, October 10, 2005 - 3:34 pm: | 
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Is there an easy way to add talkback to the 148 GTL China model? I am not really concerned about easy adjust ability, I am just so used to having it with the old DX99V that I cant stand going with out it now. |
Moonraker
Junior Member
Username: Moonraker
Post Number: 34
Registered: 3-2005
| | Posted on Monday, October 10, 2005 - 9:14 pm: |
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I have put talkback in several cobra/uniden radios by running a wire from the negative post on the speaker to the case of the radio. try different values of resistors inline to get the volume you want. I suppose you could also put a resistor from the negative side of your ext. speaker jack to the radio case insted of using the wire. I am not for sure but I think I used resistors in the 50 to 100 ohm range. I have never tried this on a cobra 148, but I don't see why it wont work.
If you loose your talkback or it gets quieter after extended talking, you need a higher wattage resistor. You can put 2 resistors together in paralell to get one higher wattage resistor, but remember you have to divide the ohms of the resistors by the number of resistors.
EX: two 100 ohm half watt resistors in paralell are equal to a 50 ohm 1 watt resistor
Hope this helps |
Outkast
Junior Member
Username: Outkast
Post Number: 19
Registered: 9-2005
| | Posted on Tuesday, October 11, 2005 - 1:24 am: |
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Thanks much Moonraker, I tried doing the resistor trick with 100 ohm as someone else in another post advised, didnt work so well squealed a bit and couldnt find anything else close so I stole a VR pot out of an old audio amp that didnt work so now I have variable talk back, only problem is I have to open the case to adjust it. Oh well just glad that it is working. How do you tell the wattage of a resistor?? I have never seen any marking that would indicate what wattage it is. |
Hotwire
Advanced Member
Username: Hotwire
Post Number: 626
Registered: 1-2005
| | Posted on Tuesday, October 11, 2005 - 10:34 am: |
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The colors of the bands around a resistor indicates the value of that resistor. |
Tech808
Moderator
Username: Tech808
Post Number: 7575
Registered: 8-2002
| | Posted on Tuesday, October 11, 2005 - 10:59 am: |
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Outkast & Others,
Here is a HELPFUL LINK to save to your Favorites for Future Use.
Calculate Resistor Values from Color Codes
Hope this helps,
Lon
Tech808
CEF808
N9OSN
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Wildrat
Intermediate Member
Username: Wildrat
Post Number: 132
Registered: 12-2003
| | Posted on Tuesday, October 11, 2005 - 12:59 pm: |
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I have a small public domain resistorvalue program if any one wants a copy. |
Wildrat
Intermediate Member
Username: Wildrat
Post Number: 133
Registered: 12-2003
| | Posted on Tuesday, October 11, 2005 - 1:00 pm: |
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I have a small public domain resistor value program if any one wants a copy.It does 3 and 4 band resistors. |
Moonraker
Junior Member
Username: Moonraker
Post Number: 37
Registered: 3-2005
| | Posted on Tuesday, October 11, 2005 - 9:11 pm: |
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The band colors indicate the ohm value and tolerance of the resistor. The only way I know to find the rated wattage is to look on the package. You do not have to use a 100 ohm resistor, you can use whatever gets you the volume you want. But I think you have got it figured out. |
