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Username: Tshelburne5002

Post Number: 7
Registered: 3-2004
Posted on Wednesday, May 05, 2004 - 12:33 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Is there any way to install a variable output power controller on these radios say like the rf output knob on a galaxy 959? I saw a radio that had this control does anyone know how to do this mod?? Also I was looking around and saw a way to install dual finals on a radio that normally only had one. Does anyone have an idea on how to do that?
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Username: Tech548

Post Number: 12
Registered: 5-2004
Posted on Wednesday, May 05, 2004 - 11:37 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)


This modification will allow you to easily drive an amplifierwithout "over-driving" it. Before you do this modification, have your radio peaked out in advance.

1- Unsolder JP-36. This will be found in the back of the radio near the final.

2- Solder a 220uF capacitor in the now emty holes where JP-36 was removed. Note: Be very sure that the negative side of the capacitor faces the final.

3- On the printed side of the board, solder a 20K verible resistor across the solder joints of the newly installed 220uF capacitor. I've seen some guys use their RF-Gain control for this-which I personally do not recomend.

As a final note, there is absolutely no advantage by doing this modification to these radios "UNLESS" you are using it to drive a linear. Other than that, the only gain you will see is having more modulation as you turn the RF power down. And, by the same token, you will see less modulation ar you turn the RF power up.

There are quite a few single-final 10 meter radios that can be had for a few bucks more than a Cobra-29 that will easily blow the doors off the Cobra-29. And most of them even feature verible power capabilities.

A verible power feature is nice to have when running an RF amplifier. Other than that, I see no advantage other than the novelty of it all.

Jeff, kc0gxz.

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